Re: [Emc-users] Carving a spiral
I have one of these... cnc'ing it would be trivial.. :) http://www.lathes.co.uk/everede/ On Sat, Apr 13, 2024 at 10:05 AM BRIAN GLACKIN wrote: > Probably way to late the discussion but…. > > In the wiki under O-word example, there is an example for a “Spirograph” > which if my maths are right would simply be a 2d spiral. > > Here’s the actual cutting snippet from the wiki. > > > > (here is the actual cutting - I don't have any z in it yet) > o250 do > #15=[[#1+#2]*COS[#4] - [#2+#3]*COS[[[#1+#2]/#2]*#4]] > #16=[[#1+#2]*sin[#4] - [#2+#3]*sin[[[#1+#2]/#2]*#4]] > g1 x[#15]y[#16]f200 > #4=[#4+#5] > o250 while [#4 LE #14] > > The only thing missing is adding in the Zed coordinate as the original > poster indicated in his comments. It is essentially a 3d helical routine. > > Sub-routines require some mental gymnastics to keep up with but can be a > “stimulating “ challenge to solve especially if it results in a reusable / > configurable tool. > > Bg > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Probably way to late the discussion but…. In the wiki under O-word example, there is an example for a “Spirograph” which if my maths are right would simply be a 2d spiral. Here’s the actual cutting snippet from the wiki. (here is the actual cutting - I don't have any z in it yet) o250 do #15=[[#1+#2]*COS[#4] - [#2+#3]*COS[[[#1+#2]/#2]*#4]] #16=[[#1+#2]*sin[#4] - [#2+#3]*sin[[[#1+#2]/#2]*#4]] g1 x[#15]y[#16]f200 #4=[#4+#5] o250 while [#4 LE #14] The only thing missing is adding in the Zed coordinate as the original poster indicated in his comments. It is essentially a 3d helical routine. Sub-routines require some mental gymnastics to keep up with but can be a “stimulating “ challenge to solve especially if it results in a reusable / configurable tool. Bg ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/13/24 01:16, John Dammeyer wrote: Here's the G-Code he used for that photo. You can see he's doing 1mm passes turning the rotary table 3 turns. His mechanics are such that it cuts air at the start and at the end of the spiral. The question I asked him which relates back to my own system is what does F300 indicate? X at 300 mm/min or the rotary table at 300 degrees per minute. Or is it both? Ie. F300 for the rotary axis is 300 degrees per minute while the X axis is 300 mm/min. G0G90 X0Y0A0Z0 G1 Z5 F100 G0 G90 X36 G1 Z-1 F100 G1 X18 A-1080 F300 G1 Z5 F100 G0G90 X36 G1 Z-2 F100 G1 X18 A-2160 F300 -Original Message- From: John Dammeyer [mailto:jo...@autoartisans.com] Sent: April 12, 2024 9:10 PM To: 'Enhanced Machine Controller (EMC)' Subject: Re: [Emc-users] Carving a spiral -Original Message- From: gene heskett [mailto:ghesk...@shentel.net] Sent: April 12, 2024 7:40 PM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Carving a spiral I see now. That looks like a scroll for a 3 jawed chuck, a much tighter twist than I had envisioned as I was imagining a turbocharger wheel in my mind. For this, Z feed here is only for DOC. And it looks as if you did well! Congratulations are in order! What mill is that? The post cover looks a lot like my go704. I have no idea. The fellow is in Europe somewhere. I think Spain. And yes. It's a scroll for a chuck. Past that I know nothing. John Cheers, Gene Heskett, CET. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/13/24 00:11, John Dammeyer wrote: -Original Message- From: gene heskett [mailto:ghesk...@shentel.net] Sent: April 12, 2024 7:40 PM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Carving a spiral I see now. That looks like a scroll for a 3 jawed chuck, a much tighter twist than I had envisioned as I was imagining a turbocharger wheel in my mind. For this, Z feed here is only for DOC. And it looks as if you did well! Congratulations are in order! What mill is that? The post cover looks a lot like my go704. I have no idea. The fellow is in Europe somewhere. I think Spain. And yes. It's a scroll for a chuck. Past that I know nothing. Thanks for the update John, I always like to know when my SWAG's are right. ;o)> John Cheers, Gene Heskett, CET. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Here's the G-Code he used for that photo. You can see he's doing 1mm passes turning the rotary table 3 turns. His mechanics are such that it cuts air at the start and at the end of the spiral. The question I asked him which relates back to my own system is what does F300 indicate? X at 300 mm/min or the rotary table at 300 degrees per minute. Or is it both? Ie. F300 for the rotary axis is 300 degrees per minute while the X axis is 300 mm/min. G0G90 X0Y0A0Z0 G1 Z5 F100 G0 G90 X36 G1 Z-1 F100 G1 X18 A-1080 F300 G1 Z5 F100 G0G90 X36 G1 Z-2 F100 G1 X18 A-2160 F300 G1 Z5 F100 G0G90 X36 G1 Z-3 F100 G1 X18 A-3240 F300 G1 Z5 F100 G0G90 X36 G1 Z-3.1 F100 G1 X18 A-4320 F400 G1 Z15 F100 G0G90 X0 > -Original Message- > From: John Dammeyer [mailto:jo...@autoartisans.com] > Sent: April 12, 2024 9:10 PM > To: 'Enhanced Machine Controller (EMC)' > Subject: Re: [Emc-users] Carving a spiral > > > -Original Message- > > From: gene heskett [mailto:ghesk...@shentel.net] > > Sent: April 12, 2024 7:40 PM > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Carving a spiral > > I see now. That looks like a scroll for a 3 jawed chuck, a much tighter > > twist than I had envisioned as I was imagining a turbocharger wheel in > > my mind. For this, Z feed here is only for DOC. And it looks as if you > > did well! Congratulations are in order! > > > > What mill is that? The post cover looks a lot like my go704. > > I have no idea. The fellow is in Europe somewhere. I think Spain. And > yes. It's a scroll for a chuck. Past that I know nothing. > > > > > > > John > > > > > Cheers, Gene Heskett, CET. > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> -Original Message- > From: gene heskett [mailto:ghesk...@shentel.net] > Sent: April 12, 2024 7:40 PM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Carving a spiral > I see now. That looks like a scroll for a 3 jawed chuck, a much tighter > twist than I had envisioned as I was imagining a turbocharger wheel in > my mind. For this, Z feed here is only for DOC. And it looks as if you > did well! Congratulations are in order! > > What mill is that? The post cover looks a lot like my go704. I have no idea. The fellow is in Europe somewhere. I think Spain. And yes. It's a scroll for a chuck. Past that I know nothing. > > > > John > > > Cheers, Gene Heskett, CET. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/12/24 18:45, John Dammeyer wrote: Hi Gene, I should knock john D's problem up in openscad, might yet if he ever gives us the whole spec so I know what he's trying to do. To me it only needs 3 axis's as long as one is rotary. Those fast A & B's I have built have been handier than sliced bread. Speeds up to around 500 rpm, plenty accurate enough for what we do. Chucks on them are printed to do one job, hold a square stick of hard maple on center. Not so much my problem as a friend was asking about doing it. I really didn't see the need for a rotary table but if a mill has a lot of backlash or just isn't super big then spirals can be difficult. Hence his idea of using the rotary table. Not so sure how well this photo will come through but this is what he turned out. For me the problem wasn't duplicating the concept in CAD but how the CAM modules created decent G-Code. I think I'll try setting up a copy of my system with the rotary axis as 'C' just to see what happens. I try to learn something new every day . I see now. That looks like a scroll for a 3 jawed chuck, a much tighter twist than I had envisioned as I was imagining a turbocharger wheel in my mind. For this, Z feed here is only for DOC. And it looks as if you did well! Congratulations are in order! What mill is that? The post cover looks a lot like my go704. John Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/12/24 11:30, Chris Albertson wrote: All very true and well for someone equipt with the income and mental gear to use that chain of tools profitably. But I'm an old Iowa farm kid, we made what we needed. The "store" was 15 miles of horse drawn wagon over a mud road the county graded about 2x a year and all of a days ride in a wagon away. So we grew it, or made it from the woodyard, whatever. 2 miles to the 1 room school, I rode an old gentle mare the first mile but had to walk the 2nd mile because there wasn't a barn for the mare during the day any closer to the school when the weather was bad. Grandpa across the road had electricity, a 32 volt delco wet glass batteries, charged by a zenith windcharger. The prop broke, so mother who was the only girl in the 1929 class on aviation technology at Des Moines Tech Hi School, proceeded to teach her father how to carve the wing chord in a new prop. Worked well in less wind than the one we could get from Chicago. That led to grandpa having the first electric washing machine in Madison County Ia when the Maytag hit & miss tried to start backwards, broke the starter gears and grandma's ankle. A wagon load of shelled corn went to town, and was replaced by an electric motor and enough heavy wire to convert the Maytag. I still wear scars on one hand from getting it caught in the wringer when I was 5. We did not want for anything, we "made do" That is a hard habit to outgrow. But today you own a computer, lots of CNC equipment, a 3D printer and education is free and just a mouse click away. None of the stuff I wrote about costs even one dollar. I’m the old ririred guy now. Fusion360 is free to use. I can print ther prats and then if. Needed sand the same design to CNC machine or to an injection molder I think you are right about relativity, Einstein very much admired James Clerk Maxwell. Someone said Einstein ”stood on the shoulders of Newton”. Einstein corrected him and said “I stood on Maxwell’s shoulders”. Thanks for the story. I always like to hear those “when I was a kid…” stories. My four grandparents were born in 1902 through 1911 they could talk about the days before radio broadcasting and one-room schoolhouses. One grandfather was a professional boxer in the 1920s and traveled a lot. But even more interesting to me, my wife’s parents and uncles were born in pre-war Japan. I think they lived through more change than any living American. Sadly the last of them is in very poor health. My wife is visting her mom in Tokyo right now. Many thanks for the flowers Chris, and while I wish a long non-alsheimers life for the MIL, I can testify that time is a one way arrow and relentless. As I rebuild the ender5+, (I'm also redoing a tronxy-400) one of the things it never did was syncing the two z screws, apparently creality figured the many point bed mesh was enough so it just paralleled two small motors. So I just swapped one Z motor for a longer one I'd removed from another printer, unplugged the other so its just a bearing, put two 20 tooth pulleys on the screws, installed a belt about 15 teeth longer than needed, and am now printing the first half of a belt tensioner so I can slightly adjust the timing of the two screws to cancel bed tilt. QIDI does that on the xmax3, works great. Set and forget, no electronics involved. I should knock john D's problem up in openscad, might yet if he ever gives us the whole spec so I know what he's trying to do. To me it only needs 3 axis's as long as one is rotary. Those fast A & B's I have built have been handier than sliced bread. Speeds up to around 500 rpm, plenty accurate enough for what we do. Chucks on them are printed to do one job, hold a square stick of hard maple on center. I didn't have what it takes to do the math to get the 7 degree load face of a buttress thread, so I just put a printed wedge under the spindle motor. Solves all that math bs in one swell foop. When all you have is a hammer, lots of stuff looks like a nail. ;o)> I think that problem will boil down to maybe three master vars, one for the X stepped by whatever make a good DOC, X and A then derived from that by trig scaling, and probably Z for the venturi curve also needed, all from the single master var being stepped. A second var manages the angles of the pie slice of material being removed and a 3rd determines the angular origin of that slice, all the rest of is done by lcnc's trig stuff. I think, given enough time, I could make it work in straight gcode probably using polar/rectangular syntax for some of it. Lcnc is often my hammer. Historically I've been very good at visualizing how mechanical things worked. At 19 I was working in a hifi store, and record changers that weren't were all put on my bench where I straitened bent parts and made them work again. Had 4 or 5 other EE (this was Iowa City, whose EE school was one of the best) students who
Re: [Emc-users] Carving a spiral
Good morning, I am sitting here at 70 wondering how people get along without 5 axis. A shop here in Wichita sent me 500 parts to run. He was running them on a 4 axis mori seiki. The runtime was a little over an hour. He wanted to clear machine time. He furnished programs, material, fixtures, cutters. The envelope was 8 inches X 4 inches X 1 inch. We called them porkchops. Flat bottom but with standing ribs at angles and contours. Long, small diameter cutters to reach small corners. I programmed the parts for my 5 axis, made new fixtures (a plate with locating bushings) and used much shorter cutters. Machine run time was now 18 minutes. You CAN do 5 axis parts on 3 axis and 4 axis machines BUT (it is a very big but) it takes more time and effort. My maternal grandparents were born in 1894 and 1895, My paternal grandparents were born in 1903 and 1904. They also had stories. regards Stuart On Fri, Apr 12, 2024 at 10:33 AM Chris Albertson wrote: > > > > All very true and well for someone equipt with the income and mental > gear to use that chain of tools profitably. But I'm an old Iowa farm kid, > we made what we needed. The "store" was 15 miles of horse drawn wagon over > a mud road the county graded about 2x a year and all of a days ride in a > wagon away. So we grew it, or made it from the woodyard, whatever. 2 miles > to the 1 room school, I rode an old gentle mare the first mile but had to > walk the 2nd mile because there wasn't a barn for the mare during the day > any closer to the school when the weather was bad. Grandpa across the road > had electricity, a 32 volt delco wet glass batteries, charged by a zenith > windcharger. The prop broke, so mother who was the only girl in the 1929 > class on aviation technology at Des Moines Tech Hi School, proceeded to > teach her father how to carve the wing chord in a new prop. Worked well in > less wind than the one we could get from Chicago. That led to grandpa > having the first electric washing machine in Madison County Ia when the > Maytag hit & miss tried to start backwards, broke the starter gears and > grandma's ankle. A wagon load of shelled corn went to town, and was > replaced by an electric motor and enough heavy wire to convert the Maytag. > I still wear scars on one hand from getting it caught in the wringer when I > was 5. We did not want for anything, we "made do" That is a hard habit to > outgrow. > > But today you own a computer, lots of CNC equipment, a 3D printer and > education is free and just a mouse click away. None of the stuff I wrote > about costs even one dollar. I’m the old ririred guy now. Fusion360 is > free to use. I can print ther prats and then if. Needed sand the same > design to CNC machine or to an injection molder > > I think you are right about relativity, Einstein very much admired James > Clerk Maxwell. Someone said Einstein ”stood on the shoulders of Newton”. > Einstein corrected him and said “I stood on Maxwell’s shoulders”. > > Thanks for the story. I always like to hear those “when I was a kid…” > stories. My four grandparents were born in 1902 through 1911 they could > talk about the days before radio broadcasting and one-room schoolhouses. > One grandfather was a professional boxer in the 1920s and traveled a lot. > But even more interesting to me, my wife’s parents and uncles were born in > pre-war Japan. I think they lived through more change than any living > American. Sadly the last of them is in very poor health. My wife is > visting her mom in Tokyo right now. > > Maybe when I am older I will talk about the days of manually driven gas > cars. > > > >> > >>> > >>> My electronics education is 100% self taught. My mother gave me an IQ > good enough to pass the CET test w/o cracking a text to study it. I > understand the physics of it including Relativity. Electronics and > Relativity go hand in hand, cannot be separated. > >>> > >>> On Apr 10, 2024, at 12:09 AM, gene heskett > wrote: > >>> > >>> On 4/10/24 01:57, John Dammeyer wrote: > A friend and I have been discussing exactly how to write the > G-Code to > create a spiral scroll. > His rotary table 90:1 reduction with a 1600 micro-step motor > could be set up > to move N steps for each step of the X axis to create the > spiral. But that > approach seems clumsy. > Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. > Without using G2 or G3 it's really just a triangle isn't it? > Move rotary > table distance A and move X axis distance A'. Do it in small > enough > increments and you get a spiral. But I feel like I'm missing > something > really simple. > >> Do you need a rotary table to cut a spiral? It is just a series > of locations in (x,y). OK, if you wanted to use only (say) the X and A > axis then you should use polar coordinates, not cartesian. The equation of > a spiral on polar coordinates is very
Re: [Emc-users] Carving a spiral
> All very true and well for someone equipt with the income and mental gear to > use that chain of tools profitably. But I'm an old Iowa farm kid, we made > what we needed. The "store" was 15 miles of horse drawn wagon over a mud > road the county graded about 2x a year and all of a days ride in a wagon > away. So we grew it, or made it from the woodyard, whatever. 2 miles to the 1 > room school, I rode an old gentle mare the first mile but had to walk the 2nd > mile because there wasn't a barn for the mare during the day any closer to > the school when the weather was bad. Grandpa across the road had electricity, > a 32 volt delco wet glass batteries, charged by a zenith windcharger. The > prop broke, so mother who was the only girl in the 1929 class on aviation > technology at Des Moines Tech Hi School, proceeded to teach her father how to > carve the wing chord in a new prop. Worked well in less wind than the one we > could get from Chicago. That led to grandpa having the first electric > washing machine in Madison County Ia when the Maytag hit & miss tried to > start backwards, broke the starter gears and grandma's ankle. A wagon load of > shelled corn went to town, and was replaced by an electric motor and enough > heavy wire to convert the Maytag. I still wear scars on one hand from getting > it caught in the wringer when I was 5. We did not want for anything, we "made > do" That is a hard habit to outgrow. But today you own a computer, lots of CNC equipment, a 3D printer and education is free and just a mouse click away. None of the stuff I wrote about costs even one dollar. I’m the old ririred guy now. Fusion360 is free to use. I can print ther prats and then if. Needed sand the same design to CNC machine or to an injection molder I think you are right about relativity, Einstein very much admired James Clerk Maxwell. Someone said Einstein ”stood on the shoulders of Newton”. Einstein corrected him and said “I stood on Maxwell’s shoulders”. Thanks for the story. I always like to hear those “when I was a kid…” stories. My four grandparents were born in 1902 through 1911 they could talk about the days before radio broadcasting and one-room schoolhouses. One grandfather was a professional boxer in the 1920s and traveled a lot. But even more interesting to me, my wife’s parents and uncles were born in pre-war Japan. I think they lived through more change than any living American. Sadly the last of them is in very poor health. My wife is visting her mom in Tokyo right now. Maybe when I am older I will talk about the days of manually driven gas cars. > >> >>> >>> My electronics education is 100% self taught. My mother gave me an IQ good >>> enough to pass the CET test w/o cracking a text to study it. I understand >>> the physics of it including Relativity. Electronics and Relativity go hand >>> in hand, cannot be separated. >>> >>> On Apr 10, 2024, at 12:09 AM, gene heskett wrote: >>> >>> On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. >> Do you need a rotary table to cut a spiral? It is just a series of >> locations in (x,y). OK, if you wanted to use only (say) the X and A >> axis then you should use polar coordinates, not cartesian. The equation >> of a spiral on polar coordinates is very simple. Then you evaluate itat >> many thousands of points and at each point write gcode to “cut to” that >> point.You would not need the rotary table. >> Also why think in micro-steps and worm gear rates, you are using LCNC to >> do the kinematics, Use millimeters. >> I think this problem shows that in some cases you really can not write >> the gcode by hand. FOr continous curves in (x,y) there might be 100,000 >> or more lines of code in the file, especially if you don’t do the cut in >> one pass. You would nee towrite software to generate the g-code. Or >> use existing software, a lot of CAD systems will do this for you >>> First, a 90/1 is quite high. I have two rotary's, both consisting of a >>> 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 >>> worm. Using a screw in the worms output hub as a single prox sensor >>> index pulse generator. To
Re: [Emc-users] Carving a spiral
On 4/12/24 01:18, Chris Albertson wrote: On Apr 11, 2024, at 11:49 AM, John Dammeyer wrote: Where I'm still having trouble is understanding the compromises. Using G02 I,J motion it's possible to specify a feed rate and spindle RPM that remains constant regardless of the spiral diameter. This approach generated by the CAM software does a number of segments. But since a spiral is continuously changing the radius doesn't this approach still create a blocky segmented series of lines? Shouldn't there really be more like a new line for every say one tenth of a degree of rotation? What you should care about is just one thing: that the resulting spiral is within tolerance. If it is done with a series of straight lines or a series of arcs should not matter. I think the example g-code below is not real. What I mean is it is not what you would use because it does the cut all at once % N1 G17 G21 G40 G90 (2 1/2 Axis Profiling) N2 T1 M06 N3 S2000 M3 N4 G0 Z11.35 N5 X-6.795 Y-2.3642 N6 G1 Z5. F745.1 N7 X-4.971 Y3.7182 F372.5 N8 G17 N9 G02X2.9354Y7.9767I6.0824J-1.824 F279.4 N10 X0.0086Y-11.1633I-3.0663J-9.3249 F372.5 N11 X-4.8878Y12.9255I-0.3348J12.4739 N12 X10.8896Y-12.3617I5.6431J-14.0447 N13 X-16.8958Y8.9702I-11.9852J13.1505 N14 X21.6077Y-2.7715I18.1973J-9.3286 N15 X-23.7802Y-5.6409I-22.9524J2.6529 N16 X22.4641Y15.1503I24.9984J6.2225 N17 X-18.2168Y-23.5731I-23.4829J-16.0603 N18 X12.0427Y30.2156I18.8718J24.7892 N19 X-3.5415Y-35.0813I-12.341J-31.5628 N20 X-6.7258Y37.3924I3.4567J36.4587 N21 X17.9557Y-36.5564I7.1836J-38.6957 N22 X-29.1519Y32.2355I-18.7497J37.6857 N23 X39.2113Y-24.4201I30.2257J-33.1012 N24 X-47.7931Y-8.2457I-40.4241J24.6445 N25 G1 X-49.1271 Y-2.0374 F745.1 N26 G0 Z11.35 N27 M30 % On the other hand with the rotary table the motion is continuous for both axis. G00 G49 G40.1 G17 G80 G50 G90 G20 (2 1/2 Axis Profiling) M6 T2 M03 S2000 G1 F100 A3600 X60 G00 Z0.2362 M5 M9 M30 However the F100 is a joke because my A axis can't run more than 7 ipm or so. I have faint memories of that from a previous discussion on how to set up the A axis. My INI file says DEFAULT_ANGULAR_VELOCITY = 90.00 MIN_ANGULAR_VELOCITY = 0 MAX_ANGULAR_VELOCITY = 180.00 I think that's in degrees per second because at a G01 F6 A3600 it takes 2 seconds to do one revolution. Now that's still plenty fast if we are slotting with a 3mm or 0.118" end mill. However the problem of SFM is now in the picture. Again, a custom G-Code solution would likely be to do something like the following. edited to add the z motion too G01 F6 A360 X10 Z-.5 F5.5 A720 X20 Z-.75 F5 A1080 X30 Z-.875 So Z is doing the venturi shape also needed. Use an rn tool so a larger DOC can be used and still get a smooth finsh. That is still only 3 axis's being moved. I still don't see the need for a 5th axis. or even the 4th. Let lcnc do the trig math, it does it well. The Z required is likely to need to be derived from a scaled up cos[0 to 90] of X and I would add the DOC increment to that. A very dry mister would be a great help. I can turn mine down to about an ounce of koolmist mix an hour. With enough air to keep the workpiece fairly clean. With a single master variable to do the pie slice and 1 more var to determine the degree at the root starting point of each slice. And so on... Picking both X resolution and A distance to create a closer to ideal SFM. I don't know if there is a G-Code that states the F rate for the A axis is in degrees per minute so it's some sort of conversion from IPM. I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis program cutting a spiral with the mill using the rotary table. But I think I agree the best way to do this is probably still by hand or with a support program that generate the G-code based on parameter input like min/max SFM. John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> On Apr 11, 2024, at 11:49 AM, John Dammeyer wrote: > > Where I'm still having trouble is understanding the compromises. > > Using G02 I,J motion it's possible to specify a feed rate and spindle RPM > that remains constant regardless of the spiral diameter. This approach > generated by the CAM software does a number of segments. But since a spiral > is continuously changing the radius doesn't this approach still create a > blocky segmented series of lines? Shouldn't there really be more like a new > line for every say one tenth of a degree of rotation? What you should care about is just one thing: that the resulting spiral is within tolerance. If it is done with a series of straight lines or a series of arcs should not matter. I think the example g-code below is not real. What I mean is it is not what you would use because it does the cut all at once > % > N1 G17 G21 G40 G90 > (2 1/2 Axis Profiling) > N2 T1 M06 > N3 S2000 M3 > N4 G0 Z11.35 > N5 X-6.795 Y-2.3642 > N6 G1 Z5. F745.1 > N7 X-4.971 Y3.7182 F372.5 > N8 G17 > N9 G02X2.9354Y7.9767I6.0824J-1.824 F279.4 > N10 X0.0086Y-11.1633I-3.0663J-9.3249 F372.5 > N11 X-4.8878Y12.9255I-0.3348J12.4739 > N12 X10.8896Y-12.3617I5.6431J-14.0447 > N13 X-16.8958Y8.9702I-11.9852J13.1505 > N14 X21.6077Y-2.7715I18.1973J-9.3286 > N15 X-23.7802Y-5.6409I-22.9524J2.6529 > N16 X22.4641Y15.1503I24.9984J6.2225 > N17 X-18.2168Y-23.5731I-23.4829J-16.0603 > N18 X12.0427Y30.2156I18.8718J24.7892 > N19 X-3.5415Y-35.0813I-12.341J-31.5628 > N20 X-6.7258Y37.3924I3.4567J36.4587 > N21 X17.9557Y-36.5564I7.1836J-38.6957 > N22 X-29.1519Y32.2355I-18.7497J37.6857 > N23 X39.2113Y-24.4201I30.2257J-33.1012 > N24 X-47.7931Y-8.2457I-40.4241J24.6445 > N25 G1 X-49.1271 Y-2.0374 F745.1 > N26 G0 Z11.35 > N27 M30 > % > > On the other hand with the rotary table the motion is continuous for both > axis. > G00 G49 G40.1 G17 G80 G50 G90 > G20 > (2 1/2 Axis Profiling) > M6 T2 > M03 S2000 > G1 F100 A3600 X60 > G00 Z0.2362 > M5 M9 > M30 > > However the F100 is a joke because my A axis can't run more than 7 ipm or so. > I have faint memories of that from a previous discussion on how to set up > the A axis. My INI file says > DEFAULT_ANGULAR_VELOCITY = 90.00 > MIN_ANGULAR_VELOCITY = 0 > MAX_ANGULAR_VELOCITY = 180.00 > > I think that's in degrees per second because at a G01 F6 A3600 it takes 2 > seconds to do one revolution. Now that's still plenty fast if we are > slotting with a 3mm or 0.118" end mill. However the problem of SFM is now in > the picture. Again, a custom G-Code solution would likely be to do > something like the following. > > G01 F6 A360 X10 > F5.5 A720 X20 > F5 A1080 X30 > > And so on... Picking both X resolution and A distance to create a closer to > ideal SFM. I don't know if there is a G-Code that states the F rate for the > A axis is in degrees per minute so it's some sort of conversion from IPM. > > I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis > program cutting a spiral with the mill using the rotary table. > > But I think I agree the best way to do this is probably still by hand or with > a support program that generate the G-code based on parameter input like > min/max SFM. > > John > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/11/24 18:56, John Dammeyer wrote: -Original Message- From: andy pugh [mailto:bodge...@gmail.com] Sent: April 11, 2024 3:16 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Carving a spiral On Thu, 11 Apr 2024 at 21:32, John Dammeyer wrote: My Harmonic drive is set up as an 'A' axis so the graphic on the screen shows the spiral being cut along the X as the work in line with X turns. I'd have to change my INI or HAL file to make the axis of rotation of the harmonic drive to be in line with the Z axis. Don't know how to do that. If you can re-orient it physically, then there is no need to change the axis name in HAL. just carry on calling it "A". True but it doesn't make a pretty tool path on the AXIS display. True here even with everything renamed. For B, I get a spinning tool image but the tool point does not describe the 50mm diameter thread its actually carving. AFATM is concerned its actually carving a straight line. The thread itself is very small changes in Y & Z per loop. John -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." � George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/11/24 18:17, andy pugh wrote: On Thu, 11 Apr 2024 at 21:32, John Dammeyer wrote: My Harmonic drive is set up as an 'A' axis so the graphic on the screen shows the spiral being cut along the X as the work in line with X turns. I'd have to change my INI or HAL file to make the axis of rotation of the harmonic drive to be in line with the Z axis. Don't know how to do that. If you can re-orient it physically, then there is no need to change the axis name in HAL. just carry on calling it "A". That is even easier, thanks Andy. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/11/24 16:30, John Dammeyer wrote: -Original Message- From: gene heskett [mailto:ghesk...@shentel.net] I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis program cutting a spiral with the mill using the rotary table. Why should you need a 5th axis? What are you going to do with it? I cannot visualize the need. But I think I agree the best way to do this is probably still by hand or with a support program that generate the G-code based on parameter input like min/max SFM. John Gene, My Harmonic drive is set up as an 'A' axis so the graphic on the screen shows the spiral being cut along the X as the work in line with X turns. I'd have to change my INI or HAL file to make the axis of rotation of the harmonic drive to be in line with the Z axis. Don't know how to do that. John Easy John. 1. Copy your present config directory, say its currently named go704-xyza, to make a go7704-xyzc directory in the configs dir. 2. Remount the table face up. 3. Rename the new .ini file to be go704-xyzc or whatever your mill is for the go704 part. 4. Do the same with the .hal file. Now edit the *-xyzc.ini file and change first the hal reference to point to the *-xyzc.hal. 4a. Change the COORDINATES string from X Y Z A to X Y Z C. 5. Then change [axis A] header to [axis C]. Start linuxcnc w/o the -l, and select the new *-xyzc config it should show you. 6. You'll likely get some .hal exits, fix those by editing the A's here and there by making them C's. Eventually you will fix the last one and it Should run although I've no clue where the jog buttons will be. Might even still be [], it depends somewhat on any other trickery you have in the config. You could do the same for a B but there's not much room on the average mill particularly the cnc conversion of a go704 as it loses around an inch of Y with the choice of screws supplied in the kit I used a decade+ ago. My 6040 is setup with a B, clear at the back of the bed because on the 6040, a medium sized gantry style mill, its the Y that is 600mm long. X is narrower, just under 400mm wide. I also have a rotary table, but at 90/1, its pretty slow. 15 secs or so to do 90 degrees. Considering its an ebay table I was amazed at its accuracy. I needed to sharpen a 10" ATBF saw blade for my table saw, set it up to polish about a thou off the face of every tooth. I got a 3 year saw blade before it put a burn mark on the next piece of cherry. Usually I got maybe 3 or 4 months out of a new blade. You'll always have the xyza to fall back to. Just remount the table, and run that config at startup. It really can be that simple once all this has been done. One after thought, I have assumed you have an index pulse generator on that table so it can be homed. Handier than sliced bread to calibrate the .ini SCALE. That is a separate subject involving lots of .hal code that can be commented out once its truly calibrated. Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: April 11, 2024 3:16 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Carving a spiral > > On Thu, 11 Apr 2024 at 21:32, John Dammeyer > wrote: > > > > > My Harmonic drive is set up as an 'A' axis so the graphic on the screen > > shows the spiral being cut along the X as the work in line with X turns. > > > > I'd have to change my INI or HAL file to make the axis of rotation of the > > harmonic drive to be in line with the Z axis. Don't know how to do that. > > > If you can re-orient it physically, then there is no need to change the > axis name in HAL. just carry on calling it "A". True but it doesn't make a pretty tool path on the AXIS display. John > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is designed > for the especial use of mechanical geniuses, daredevils and lunatics." > � George Fitch, Atlanta Constitution Newspaper, 1912 > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Inverse time mode? G93? Martin From: John Dammeyer Sent: Thursday, April 11, 2024 1:49 PM To: 'Enhanced Machine Controller (EMC)' Subject: Re: [Emc-users] Carving a spiral Where I'm still having trouble is understanding the compromises. Using G02 I,J motion it's possible to specify a feed rate and spindle RPM that remains constant regardless of the spiral diameter. This approach generated by the CAM software does a number of segments. But since a spiral is continuously changing the radius doesn't this approach still create a blocky segmented series of lines? Shouldn't there really be more like a new line for every say one tenth of a degree of rotation? % N1 G17 G21 G40 G90 (2 1/2 Axis Profiling) N2 T1 M06 N3 S2000 M3 N4 G0 Z11.35 N5 X-6.795 Y-2.3642 N6 G1 Z5. F745.1 N7 X-4.971 Y3.7182 F372.5 N8 G17 N9 G02X2.9354Y7.9767I6.0824J-1.824 F279.4 N10 X0.0086Y-11.1633I-3.0663J-9.3249 F372.5 N11 X-4.8878Y12.9255I-0.3348J12.4739 N12 X10.8896Y-12.3617I5.6431J-14.0447 N13 X-16.8958Y8.9702I-11.9852J13.1505 N14 X21.6077Y-2.7715I18.1973J-9.3286 N15 X-23.7802Y-5.6409I-22.9524J2.6529 N16 X22.4641Y15.1503I24.9984J6.2225 N17 X-18.2168Y-23.5731I-23.4829J-16.0603 N18 X12.0427Y30.2156I18.8718J24.7892 N19 X-3.5415Y-35.0813I-12.341J-31.5628 N20 X-6.7258Y37.3924I3.4567J36.4587 N21 X17.9557Y-36.5564I7.1836J-38.6957 N22 X-29.1519Y32.2355I-18.7497J37.6857 N23 X39.2113Y-24.4201I30.2257J-33.1012 N24 X-47.7931Y-8.2457I-40.4241J24.6445 N25 G1 X-49.1271 Y-2.0374 F745.1 N26 G0 Z11.35 N27 M30 % On the other hand with the rotary table the motion is continuous for both axis. G00 G49 G40.1 G17 G80 G50 G90 G20 (2 1/2 Axis Profiling) M6 T2 M03 S2000 G1 F100 A3600 X60 G00 Z0.2362 M5 M9 M30 However the F100 is a joke because my A axis can't run more than 7 ipm or so. I have faint memories of that from a previous discussion on how to set up the A axis. My INI file says DEFAULT_ANGULAR_VELOCITY = 90.00 MIN_ANGULAR_VELOCITY = 0 MAX_ANGULAR_VELOCITY = 180.00 I think that's in degrees per second because at a G01 F6 A3600 it takes 2 seconds to do one revolution. Now that's still plenty fast if we are slotting with a 3mm or 0.118" end mill. However the problem of SFM is now in the picture. Again, a custom G-Code solution would likely be to do something like the following. G01 F6 A360 X10 F5.5 A720 X20 F5 A1080 X30 And so on... Picking both X resolution and A distance to create a closer to ideal SFM. I don't know if there is a G-Code that states the F rate for the A axis is in degrees per minute so it's some sort of conversion from IPM. I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis program cutting a spiral with the mill using the rotary table. But I think I agree the best way to do this is probably still by hand or with a support program that generate the G-code based on parameter input like min/max SFM. John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users=05%7C02%7C%7C0eda66fa23fc41214ccc08dc5a587b91%7C84df9e7fe9f640afb435%7C1%7C0%7C638484583297991846%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C=5LShxguCKIgbKdvY9rrmbyh3S%2BQ92nf56AKz2FMHEqU%3D=0<https://lists.sourceforge.net/lists/listinfo/emc-users> ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On Thu, 11 Apr 2024 at 21:32, John Dammeyer wrote: > > My Harmonic drive is set up as an 'A' axis so the graphic on the screen > shows the spiral being cut along the X as the work in line with X turns. > > I'd have to change my INI or HAL file to make the axis of rotation of the > harmonic drive to be in line with the Z axis. Don't know how to do that. If you can re-orient it physically, then there is no need to change the axis name in HAL. just carry on calling it "A". -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> -Original Message- > From: gene heskett [mailto:ghesk...@shentel.net] > > I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis > program cutting a spiral with the mill using the rotary table. > > Why should you need a 5th axis? What are you going to do with it? I > cannot visualize the need. > > > But I think I agree the best way to do this is probably still by hand or with a > support program that generate the G-code based on parameter input like > min/max SFM. > > > > John Gene, My Harmonic drive is set up as an 'A' axis so the graphic on the screen shows the spiral being cut along the X as the work in line with X turns. I'd have to change my INI or HAL file to make the axis of rotation of the harmonic drive to be in line with the Z axis. Don't know how to do that. John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/11/24 14:50, John Dammeyer wrote: Where I'm still having trouble is understanding the compromises. Using G02 I,J motion it's possible to specify a feed rate and spindle RPM that remains constant regardless of the spiral diameter. This approach generated by the CAM software does a number of segments. But since a spiral is continuously changing the radius doesn't this approach still create a blocky segmented series of lines? Shouldn't there really be more like a new line for every say one tenth of a degree of rotation? % N1 G17 G21 G40 G90 (2 1/2 Axis Profiling) N2 T1 M06 N3 S2000 M3 N4 G0 Z11.35 N5 X-6.795 Y-2.3642 N6 G1 Z5. F745.1 N7 X-4.971 Y3.7182 F372.5 N8 G17 N9 G02X2.9354Y7.9767I6.0824J-1.824 F279.4 N10 X0.0086Y-11.1633I-3.0663J-9.3249 F372.5 N11 X-4.8878Y12.9255I-0.3348J12.4739 N12 X10.8896Y-12.3617I5.6431J-14.0447 N13 X-16.8958Y8.9702I-11.9852J13.1505 N14 X21.6077Y-2.7715I18.1973J-9.3286 N15 X-23.7802Y-5.6409I-22.9524J2.6529 N16 X22.4641Y15.1503I24.9984J6.2225 N17 X-18.2168Y-23.5731I-23.4829J-16.0603 N18 X12.0427Y30.2156I18.8718J24.7892 N19 X-3.5415Y-35.0813I-12.341J-31.5628 N20 X-6.7258Y37.3924I3.4567J36.4587 N21 X17.9557Y-36.5564I7.1836J-38.6957 N22 X-29.1519Y32.2355I-18.7497J37.6857 N23 X39.2113Y-24.4201I30.2257J-33.1012 N24 X-47.7931Y-8.2457I-40.4241J24.6445 N25 G1 X-49.1271 Y-2.0374 F745.1 N26 G0 Z11.35 N27 M30 % On the other hand with the rotary table the motion is continuous for both axis. G00 G49 G40.1 G17 G80 G50 G90 G20 (2 1/2 Axis Profiling) M6 T2 M03 S2000 G1 F100 A3600 X60 G00 Z0.2362 M5 M9 M30 However the F100 is a joke because my A axis can't run more than 7 ipm or so. I have faint memories of that from a previous discussion on how to set up the A axis. My INI file says DEFAULT_ANGULAR_VELOCITY = 90.00 MIN_ANGULAR_VELOCITY = 0 MAX_ANGULAR_VELOCITY = 180.00 I think that's in degrees per second because at a G01 F6 A3600 it takes 2 seconds to do one revolution. Now that's still plenty fast if we are slotting with a 3mm or 0.118" end mill. However the problem of SFM is now in the picture. Again, a custom G-Code solution would likely be to do something like the following. G01 F6 A360 X10 F5.5 A720 X20 F5 A1080 X30 And so on... Picking both X resolution and A distance to create a closer to ideal SFM. I don't know if there is a G-Code that states the F rate for the A axis is in degrees per minute so it's some sort of conversion from IPM. A rotary axis is normally speced in 1 degree pieces, ANGULAR and degree being the key words. AFAIK, if ANGULAR, it never is IPM. I suppose one might use radians instead of degrees or one of the other names for rotary stuff. I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis program cutting a spiral with the mill using the rotary table. Why should you need a 5th axis? What are you going to do with it? I cannot visualize the need. But I think I agree the best way to do this is probably still by hand or with a support program that generate the G-code based on parameter input like min/max SFM. John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/11/24 13:49, Chris Albertson wrote: On Apr 11, 2024, at 9:05 AM, gene heskett wrote: On 4/11/24 11:38, Chris Albertson wrote: On Apr 10, 2024, at 1:14 PM, gene heskett wrote: On 4/10/24 13:30, Chris Albertson wrote: Do you even need a rotory table to cut a spiral? Now that you ask, I think the answer is probably no. Take a look at the nurbs command G5.2 where a group of points describes the curve. Then rotate the points about one end in polar/rectangular space. I haven't played with that myself, perhaps Andy has a better way? If you know how to find the 3 or 5 or 10 points that define the curve, then you can use the same method to find 10,000 point on that curve and just do a straight line between them. Finally to TEST your idea, you need a way to calculate the error. You find the exact solution for any arbitary point and then to compare that to what you are doing. If you know how to calulate the exact solution, then why bother with approxomations like nurbs? The nuirbs thing is for filling in points you have no way of knowing. What nurbs is good for is when you want to mill a copy of some object that you don’t have an exact solution for. The perfect example is that you were given an STL and all they have is triangle vertici. You can’t know where the STL got its shape, is the curve a circle, elipse or an artest’s pen stroke. But the nurbs-like or spline-like fitting funtion will generate a smooth curve through the list of points. All of the above is my weak point. I only got to a couple months of my freshman year in high school, and the math teacher fancied himself as a standup commedian, far more interested in what was in the girls panties that in teaching math. The best way to catch up on math is Kahn Academy. The instructor who makes the videos is a very good teacher. He covers from kindergarten (literally) to lower division university level, although the more advanced math is taught is a slightly less rigorous level than at most universities. what is a Good Thing if you are an engineer or scientist who cares more about practice than theory I did study the full program of undergrad math but that was. in the 1970s and 80s. I had forgotten most Linear Algebra and quite a lot of Calculus. Then I got interested in robots and for that, you pretty much need what I had forgotten. Kahn Academy is ideal for as a refresh class. But you have to invest some time. He covers a full semester of material in each course. Electronics is so very much dependent on math that many would-be electrical engineers switch majors to civil or environmental engineering because the math is easier Back to g-codes.It should not be a surprise that the g-code for complex shapes is either volumes or very complex. Just look at the 3D printer. No one would attempt to hand code, even a simple printed part can have 200,000 lines of code. So we use software to generate the code and it takes usually less than two seconds. Cutting a scroll on a CNC mill is a really hard problem if you care to get it correct. That means (1) the result is within tolerance, (2) cutting at optimal feed rate, (3) roughing and finish passes with tool changes. The way I’d do this is to model it in Fusion360 and then send the file to my 3D printer to make a working prototype. After seeing that the plastic part is correct and fits the rest of the machine I’m making then I’d send the same Fusion360 file to CAM software to create g-code for milling. Becuse the same design file feeds both the printer and the CNC mill, I can have some confidence that the plastic part will match the metal part. All very true and well for someone equipt with the income and mental gear to use that chain of tools profitably. But I'm an old Iowa farm kid, we made what we needed. The "store" was 15 miles of horse drawn wagon over a mud road the county graded about 2x a year and all of a days ride in a wagon away. So we grew it, or made it from the woodyard, whatever. 2 miles to the 1 room school, I rode an old gentle mare the first mile but had to walk the 2nd mile because there wasn't a barn for the mare during the day any closer to the school when the weather was bad. Grandpa across the road had electricity, a 32 volt delco wet glass batteries, charged by a zenith windcharger. The prop broke, so mother who was the only girl in the 1929 class on aviation technology at Des Moines Tech Hi School, proceeded to teach her father how to carve the wing chord in a new prop. Worked well in less wind than the one we could get from Chicago. That led to grandpa having the first electric washing machine in Madison County Ia when the Maytag hit & miss tried to start backwards, broke the starter gears and grandma's ankle. A wagon load of shelled corn went to town, and was replaced by an electric motor and enough heavy wire to convert the Maytag. I still wear scars on one hand from
Re: [Emc-users] Carving a spiral
Where I'm still having trouble is understanding the compromises. Using G02 I,J motion it's possible to specify a feed rate and spindle RPM that remains constant regardless of the spiral diameter. This approach generated by the CAM software does a number of segments. But since a spiral is continuously changing the radius doesn't this approach still create a blocky segmented series of lines? Shouldn't there really be more like a new line for every say one tenth of a degree of rotation? % N1 G17 G21 G40 G90 (2 1/2 Axis Profiling) N2 T1 M06 N3 S2000 M3 N4 G0 Z11.35 N5 X-6.795 Y-2.3642 N6 G1 Z5. F745.1 N7 X-4.971 Y3.7182 F372.5 N8 G17 N9 G02X2.9354Y7.9767I6.0824J-1.824 F279.4 N10 X0.0086Y-11.1633I-3.0663J-9.3249 F372.5 N11 X-4.8878Y12.9255I-0.3348J12.4739 N12 X10.8896Y-12.3617I5.6431J-14.0447 N13 X-16.8958Y8.9702I-11.9852J13.1505 N14 X21.6077Y-2.7715I18.1973J-9.3286 N15 X-23.7802Y-5.6409I-22.9524J2.6529 N16 X22.4641Y15.1503I24.9984J6.2225 N17 X-18.2168Y-23.5731I-23.4829J-16.0603 N18 X12.0427Y30.2156I18.8718J24.7892 N19 X-3.5415Y-35.0813I-12.341J-31.5628 N20 X-6.7258Y37.3924I3.4567J36.4587 N21 X17.9557Y-36.5564I7.1836J-38.6957 N22 X-29.1519Y32.2355I-18.7497J37.6857 N23 X39.2113Y-24.4201I30.2257J-33.1012 N24 X-47.7931Y-8.2457I-40.4241J24.6445 N25 G1 X-49.1271 Y-2.0374 F745.1 N26 G0 Z11.35 N27 M30 % On the other hand with the rotary table the motion is continuous for both axis. G00 G49 G40.1 G17 G80 G50 G90 G20 (2 1/2 Axis Profiling) M6 T2 M03 S2000 G1 F100 A3600 X60 G00 Z0.2362 M5 M9 M30 However the F100 is a joke because my A axis can't run more than 7 ipm or so. I have faint memories of that from a previous discussion on how to set up the A axis. My INI file says DEFAULT_ANGULAR_VELOCITY = 90.00 MIN_ANGULAR_VELOCITY = 0 MAX_ANGULAR_VELOCITY = 180.00 I think that's in degrees per second because at a G01 F6 A3600 it takes 2 seconds to do one revolution. Now that's still plenty fast if we are slotting with a 3mm or 0.118" end mill. However the problem of SFM is now in the picture. Again, a custom G-Code solution would likely be to do something like the following. G01 F6 A360 X10 F5.5 A720 X20 F5 A1080 X30 And so on... Picking both X resolution and A distance to create a closer to ideal SFM. I don't know if there is a G-Code that states the F rate for the A axis is in degrees per minute so it's some sort of conversion from IPM. I only have the 4th Axis version of MECSOFT so I can't generate a fifth axis program cutting a spiral with the mill using the rotary table. But I think I agree the best way to do this is probably still by hand or with a support program that generate the G-code based on parameter input like min/max SFM. John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> On Apr 11, 2024, at 9:05 AM, gene heskett wrote: > > On 4/11/24 11:38, Chris Albertson wrote: >>> On Apr 10, 2024, at 1:14 PM, gene heskett wrote: >>> >>> On 4/10/24 13:30, Chris Albertson wrote: Do you even need a rotory table to cut a spiral? >>> >>> Now that you ask, I think the answer is probably no. Take a look at the >>> nurbs command G5.2 where a group of points describes the curve. Then rotate >>> the points about one end in polar/rectangular space. I haven't played with >>> that myself, perhaps Andy has a better way? >> If you know how to find the 3 or 5 or 10 points that define the curve, then >> you can use the same method to find 10,000 point on that curve and just do a >> straight line between them. >> Finally to TEST your idea, you need a way to calculate the error. You find >> the exact solution for any arbitary point and then to compare that to what >> you are doing. If you know how to calulate the exact solution, then why >> bother with approxomations like nurbs? The nuirbs thing is for filling in >> points you have no way of knowing. >> What nurbs is good for is when you want to mill a copy of some object that >> you don’t have an exact solution for. The perfect example is that you were >> given an STL and all they have is triangle vertici. You can’t know where >> the STL got its shape, is the curve a circle, elipse or an artest’s pen >> stroke. But the nurbs-like or spline-like fitting funtion will generate a >> smooth curve through the list of points. > All of the above is my weak point. I only got to a couple months of my > freshman year in high school, and the math teacher fancied himself as a > standup commedian, far more interested in what was in the girls panties that > in teaching math. The best way to catch up on math is Kahn Academy. The instructor who makes the videos is a very good teacher. He covers from kindergarten (literally) to lower division university level, although the more advanced math is taught is a slightly less rigorous level than at most universities. what is a Good Thing if you are an engineer or scientist who cares more about practice than theory I did study the full program of undergrad math but that was. in the 1970s and 80s. I had forgotten most Linear Algebra and quite a lot of Calculus. Then I got interested in robots and for that, you pretty much need what I had forgotten. Kahn Academy is ideal for as a refresh class. But you have to invest some time. He covers a full semester of material in each course. Electronics is so very much dependent on math that many would-be electrical engineers switch majors to civil or environmental engineering because the math is easier Back to g-codes.It should not be a surprise that the g-code for complex shapes is either volumes or very complex. Just look at the 3D printer. No one would attempt to hand code, even a simple printed part can have 200,000 lines of code. So we use software to generate the code and it takes usually less than two seconds. Cutting a scroll on a CNC mill is a really hard problem if you care to get it correct. That means (1) the result is within tolerance, (2) cutting at optimal feed rate, (3) roughing and finish passes with tool changes. The way I’d do this is to model it in Fusion360 and then send the file to my 3D printer to make a working prototype. After seeing that the plastic part is correct and fits the rest of the machine I’m making then I’d send the same Fusion360 file to CAM software to create g-code for milling. Becuse the same design file feeds both the printer and the CNC mill, I can have some confidence that the plastic part will match the metal part. > > My electronics education is 100% self taught. My mother gave me an IQ good > enough to pass the CET test w/o cracking a text to study it. I understand the > physics of it including Relativity. Electronics and Relativity go hand in > hand, cannot be separated. > > On Apr 10, 2024, at 12:09 AM, gene heskett wrote: > > On 4/10/24 01:57, John Dammeyer wrote: >> A friend and I have been discussing exactly how to write the G-Code to >> create a spiral scroll. >> His rotary table 90:1 reduction with a 1600 micro-step motor could be >> set up >> to move N steps for each step of the X axis to create the spiral. But >> that >> approach seems clumsy. >> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. >> Without using G2 or G3 it's really just a triangle isn't it? Move >> rotary >> table distance A and move X axis distance A'. Do it in small enough >> increments and you get a spiral. But I feel like I'm missing something >> really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not
Re: [Emc-users] Carving a spiral
On 4/11/24 11:41, Chris Albertson wrote: On Apr 10, 2024, at 12:47 PM, gene heskett wrote: On 4/10/24 13:03, John Dammeyer wrote: Hi Gene, Just like I can't get my head around Fusion360 or similar CAD. I find that many people’s problem is that they are still thinking that CAD is used to “draw” a part and that somehow the final product is a “‘drawing”. This is completely contrary to how it works. What you do is make the part, just like you would in the shop. There is no “drawing”. In the shop you might start with an extrusion then cut it and mill a pocket and then make some holes and then what ever until it was the right shape. With CAD now, the first step is usually drawing the profile for a custom extrusion. If you try and hand code gcode or use OpenSCAD you are limited to very simple shapes and can never exploit the full capability of the milling machine. Just TRY and hand code a typical hand-held power tool or even a triangular pocket on the side of the sphere in hand-written gcode. So, if you want to model a part in CAD, just think how you would make it in a very well equipped shop. All extremely true. But as I approach my 90th, its a bit late to try and learn a 10 grand a year CAD/CAM program that can do all that. What I need in rebuilding a burned up 3d printer, I can knock up in OpenSCAD in an hour or 2, and have in my hands ready to bolt it in, in the time it takes a QIDI XMax-3 to print it. May not impress the girls, but it will work. AlibreCAD has gone downhill since they trashed their relationship with MecSoft which correspondingly trashed AlibreCAM. I'll take a closer look at your approach later today. My approaches subroutine will take a loop as the primary slicer because each piece of the scroll will need to start at the root of that slice but the curved pie slice is wider at the outside. A spiral is a continuous curve, already we jhave assen the curve’s equation. You just marchthrough the point the equation producse and it is literally “perfect”, no approximation. The only problems left are 1) The method is “too perfect” and will generate to make points and be slow 2) doing it all in one pass is a poor machining technique. The target is to carve each slice from its apex point but widen the rim so that your 3mm wide fin is all that's left, then advance to the apex of the next pie slice. So the subroutine will start at 6 common points around the central axis, and you wind up with 6 3mm wide fins in the scroll shape. That won't be the most efficient shape but will get you started. To improve the efficiency, that central subroutine will need to be converted to use G4 nurbs to describe the spiral path. But that's for next week. And I expect Andy might have some better ideas on the nurbs points. I have a good idea what they can do but zip about the math involved. Flow thru a venturi etc type math. Thanks John -Original Message- From: gene heskett [mailto:ghesk...@shentel.net] Sent: April 10, 2024 3:42 AM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Carving a spiral On 4/10/24 03:37, John Dammeyer wrote: Hi Marcus, Here's the problem. My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y motion. I looked at alibre, could not get my Iowa farm kid head around it. Far easier for me to write my own gcode. In linuxcnc, you can trade the axis names around to fit your hdwe. How far can you tilt your Z? Mine can do a full 90, aka lay the spindle horizontal. Either way IIRC. I can then use X as X, A as A, and a single straight line move to carve the spiral using Z while A is turning N degrees to carve the spiral. So the gcode then becomes a subroutine to do that, and a 2nd loop routine to handle the start of the spiral and possibly a master outer loop to do any incremental cuts to get to the depth needed. Maybe 80 LOC total. If your head cannot tilt that far, then you''l have to cobble up a C, facing up which I CAN do but its a 90/1 drive and will restrict the speed as It can't turn fast enough. Also has a std stepper motor, push its speed and it stalls. Someday I'll put a good motor on it. A Warning though, most of the combo gizmos they sell for $300 or so on ebay are belt drive and no-where near strong enough for this. I did use my 90/1 as A when making my tap hats. Used it to drill & tap the 4 grub screw holes. I setup workstations on the length of the go704's table, put a piece of brass rod in the spindle, drilled the hole for the tap, move the brass to a clamp, drilled and tapped for a locking to an r8 collet screw hole, moved the brass to the A chuck and drilled and tapped all 4 grub screws. All in the same gcode file with pauses and automatic tlo offset corrections as the drills were different lengths. Made a regular production line out of it, took longer moving the brass around than the total run time for the machine. If I tell it to use my 4th axis it's like the v
Re: [Emc-users] Carving a spiral
On 4/11/24 11:38, Chris Albertson wrote: On Apr 10, 2024, at 1:14 PM, gene heskett wrote: On 4/10/24 13:30, Chris Albertson wrote: Do you even need a rotory table to cut a spiral? Now that you ask, I think the answer is probably no. Take a look at the nurbs command G5.2 where a group of points describes the curve. Then rotate the points about one end in polar/rectangular space. I haven't played with that myself, perhaps Andy has a better way? If you know how to find the 3 or 5 or 10 points that define the curve, then you can use the same method to find 10,000 point on that curve and just do a straight line between them. Finally to TEST your idea, you need a way to calculate the error. You find the exact solution for any arbitary point and then to compare that to what you are doing. If you know how to calulate the exact solution, then why bother with approxomations like nurbs? The nuirbs thing is for filling in points you have no way of knowing. What nurbs is good for is when you want to mill a copy of some object that you don’t have an exact solution for. The perfect example is that you were given an STL and all they have is triangle vertici. You can’t know where the STL got its shape, is the curve a circle, elipse or an artest’s pen stroke. But the nurbs-like or spline-like fitting funtion will generate a smooth curve through the list of points. All of the above is my weak point. I only got to a couple months of my freshman year in high school, and the math teacher fancied himself as a standup commedian, far more interested in what was in the girls panties that in teaching math. And eventually got ran out of town by an irate father with a 12ga in hand cuz a 13 year old he got pregnant was his daughter. My electronics education is 100% self taught. My mother gave me an IQ good enough to pass the CET test w/o cracking a text to study it. I understand the physics of it including Relativity. Electronics and Relativity go hand in hand, cannot be separated. On Apr 10, 2024, at 12:09 AM, gene heskett wrote: On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not cartesian. The equation of a spiral on polar coordinates is very simple. Then you evaluate itat many thousands of points and at each point write gcode to “cut to” that point.You would not need the rotary table. Also why think in micro-steps and worm gear rates, you are using LCNC to do the kinematics, Use millimeters. I think this problem shows that in some cases you really can not write the gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more lines of code in the file, especially if you don’t do the cut in one pass. You would nee towrite software to generate the g-code. Or use existing software, a lot of CAD systems will do this for you First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using a screw in the worms output hub as a single prox sensor index pulse generator. To calibrate a complete rev, I measure the steps by starting the count on the 3rd turn ans stopping the count on the 103rd turn, which gives me a scale*100. Shift the decimal point 2 places left this becomes the scale for the axis in the .ini file. All this math in linuxcnc is floating point so I can ask it for 33.333 degrees and it will run to what it thinks is 33.333 degrees. This stepscale: STEPSCALE = 22.222 = 1 degree So one count is about 1/22.222 degrees, probably less than the backlash in the rvs39 worm, a pretty cheap worm. Currently to make one of my maple vise screws, starting at 0 degrees its around 60,000 degrees it turns for around 400 mm of screw that y travels. Then I lift the tool, turn it another 180 degrees, re lower the tool and bring y back to zero and b=180. Makes a perfect two start buttress thread. The B is turning, in perfect sync with the Y motion, at something in the 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. There is no reason you couldn't lay it down to make a C drive, and simultaneously drive X Z & C to carve an impeller in a quite serviceable scroll. The
Re: [Emc-users] Carving a spiral
> On Apr 10, 2024, at 12:47 PM, gene heskett wrote: > > On 4/10/24 13:03, John Dammeyer wrote: >> Hi Gene, >> Just like I can't get my head around Fusion360 or similar CAD. I find that many people’s problem is that they are still thinking that CAD is used to “draw” a part and that somehow the final product is a “‘drawing”. This is completely contrary to how it works. What you do is make the part, just like you would in the shop. There is no “drawing”. In the shop you might start with an extrusion then cut it and mill a pocket and then make some holes and then what ever until it was the right shape. With CAD now, the first step is usually drawing the profile for a custom extrusion. If you try and hand code gcode or use OpenSCAD you are limited to very simple shapes and can never exploit the full capability of the milling machine. Just TRY and hand code a typical hand-held power tool or even a triangular pocket on the side of the sphere in hand-written gcode. So, if you want to model a part in CAD, just think how you would make it in a very well equipped shop. >> AlibreCAD has gone downhill since they trashed their relationship with >> MecSoft which correspondingly trashed AlibreCAM. >> I'll take a closer look at your approach later today. > > My approaches subroutine will take a loop as the primary slicer because each > piece of the scroll will need to start at the root of that slice but the > curved pie slice is wider at the outside. A spiral is a continuous curve, already we jhave assen the curve’s equation. You just marchthrough the point the equation producse and it is literally “perfect”, no approximation. The only problems left are 1) The method is “too perfect” and will generate to make points and be slow 2) doing it all in one pass is a poor machining technique. > The target is to carve each slice from its apex point but widen the rim so > that your 3mm wide fin is all that's left, then advance to the apex of the > next pie slice. So the subroutine will start at 6 common points around the > central axis, and you wind up with 6 3mm wide fins in the scroll shape. > > That won't be the most efficient shape but will get you started. To improve > the efficiency, that central subroutine will need to be converted to use G4 > nurbs to describe the spiral path. But that's for next week. And I expect > Andy might have some better ideas on the nurbs points. I have a good idea > what they can do but zip about the math involved. Flow thru a venturi etc > type math. > >> Thanks >> John >>> -Original Message- >>> From: gene heskett [mailto:ghesk...@shentel.net] >>> Sent: April 10, 2024 3:42 AM >>> To: emc-users@lists.sourceforge.net >>> Subject: Re: [Emc-users] Carving a spiral >>> >>> On 4/10/24 03:37, John Dammeyer wrote: >>>> Hi Marcus, >>>> >>>> Here's the problem. >>>> >>>> My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y >> motion. >>> >>> I looked at alibre, could not get my Iowa farm kid head around it. Far >>> easier for me to write my own gcode. >>> >>> In linuxcnc, you can trade the axis names around to fit your hdwe. >>> >>> How far can you tilt your Z? Mine can do a full 90, aka lay the spindle >>> horizontal. Either way IIRC. I can then use X as X, A as A, and a >>> single straight line move to carve the spiral using Z while A is turning >>> N degrees to carve the spiral. So the gcode then becomes a subroutine to >>> do that, and a 2nd loop routine to handle the start of the spiral and >>> possibly a master outer loop to do any incremental cuts to get to the >>> depth needed. Maybe 80 LOC total. >>> >>> If your head cannot tilt that far, then you''l have to cobble up a C, >>> facing up which I CAN do but its a 90/1 drive and will restrict the >>> speed as It can't turn fast enough. Also has a std stepper motor, push >>> its speed and it stalls. Someday I'll put a good motor on it. >>> >>> A Warning though, most of the combo gizmos they sell for $300 or so on >>> ebay are belt drive and no-where near strong enough for this. I did use >>> my 90/1 as A when making my tap hats. Used it to drill & tap the 4 grub >>> screw holes. I setup workstations on the length of the go704's table, >>> put a piece of brass rod in the spindle, drilled the hole for the tap, >>> move the brass to a clamp, drilled and tapped for a locking to an r8 >>> collet screw hole, moved the brass to the A chuck and drilled and tapped >>> all 4 grub screws. All in the
Re: [Emc-users] Carving a spiral
> On Apr 10, 2024, at 1:14 PM, gene heskett wrote: > > On 4/10/24 13:30, Chris Albertson wrote: >> Do you even need a rotory table to cut a spiral? > > Now that you ask, I think the answer is probably no. Take a look at the nurbs > command G5.2 where a group of points describes the curve. Then rotate the > points about one end in polar/rectangular space. I haven't played with that > myself, perhaps Andy has a better way? If you know how to find the 3 or 5 or 10 points that define the curve, then you can use the same method to find 10,000 point on that curve and just do a straight line between them. Finally to TEST your idea, you need a way to calculate the error. You find the exact solution for any arbitary point and then to compare that to what you are doing. If you know how to calulate the exact solution, then why bother with approxomations like nurbs? The nuirbs thing is for filling in points you have no way of knowing. What nurbs is good for is when you want to mill a copy of some object that you don’t have an exact solution for. The perfect example is that you were given an STL and all they have is triangle vertici. You can’t know where the STL got its shape, is the curve a circle, elipse or an artest’s pen stroke. But the nurbs-like or spline-like fitting funtion will generate a smooth curve through the list of points. >>> On Apr 10, 2024, at 12:09 AM, gene heskett wrote: >>> >>> On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. >> Do you need a rotary table to cut a spiral? It is just a series of >> locations in (x,y). OK, if you wanted to use only (say) the X and A axis >> then you should use polar coordinates, not cartesian. The equation of a >> spiral on polar coordinates is very simple. Then you evaluate itat many >> thousands of points and at each point write gcode to “cut to” that point. >> You would not need the rotary table. >> Also why think in micro-steps and worm gear rates, you are using LCNC to do >> the kinematics, Use millimeters. >> I think this problem shows that in some cases you really can not write the >> gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more >> lines of code in the file, especially if you don’t do the cut in one pass. >> You would nee towrite software to generate the g-code. Or use existing >> software, a lot of CAD systems will do this for you >>> First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM >>> 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. >>> Using a screw in the worms output hub as a single prox sensor index pulse >>> generator. To calibrate a complete rev, I measure the steps by starting the >>> count on the 3rd turn ans stopping the count on the 103rd turn, which gives >>> me a scale*100. Shift the decimal point 2 places left this becomes the >>> scale for the axis in the .ini file. All this math in linuxcnc is floating >>> point so I can ask it for 33.333 degrees and it will run to what it thinks >>> is 33.333 degrees. This stepscale: >>> STEPSCALE = 22.222 = 1 degree >>> So one count is about 1/22.222 degrees, probably less than the >>> backlash in the rvs39 worm, a pretty cheap worm. >>> >>> Currently to make one of my maple vise screws, starting at 0 degrees its >>> around 60,000 degrees it turns for around 400 mm of screw that y travels. >>> Then I lift the tool, turn it another 180 degrees, re lower the tool and >>> bring y back to zero and b=180. Makes a perfect two start buttress thread. >>> The B is turning, in perfect sync with the Y motion, at something in the >>> 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. >>> >>> There is no reason you couldn't lay it down to make a C drive, and >>> simultaneously drive X Z & C to carve an impeller in a quite serviceable >>> scroll. >>> >>> The versatility of the closed loop stepper/servo, which does EXACTLY what >>> the TP tells it to do, without a PID in the path, is amazing. I have them >>> rigged to e-stop linuxcnc in about a millisecond if they make an error, >>> like losing a step. Tested till the cows come home, has yet to happen >>> working a job. I haven't hobbed any gears, but it certainly seems accurate >>> enough to do it. >>> Suggestions? Thanks John
Re: [Emc-users] Carving a spiral
https://www.britannica.com/science/spiral-mathematics Several options here, take your pick. Should be trivial to move it from floating pt to fixed. May have to scale to make it happy. ;-) Dave > On Apr 10, 2024, at 12:09 AM, gene heskett wrote: > > On 4/10/24 01:57, John Dammeyer wrote: >> A friend and I have been discussing exactly how to write the G-Code to >> create a spiral scroll. >> His rotary table 90:1 reduction with a 1600 micro-step motor could be set up >> to move N steps for each step of the X axis to create the spiral. But that >> approach seems clumsy. >> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. >> Without using G2 or G3 it's really just a triangle isn't it? Move rotary >> table distance A and move X axis distance A'. Do it in small enough >> increments and you get a spiral. But I feel like I'm missing something >> really simple. > First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM > 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using > a screw in the worms output hub as a single prox sensor index pulse > generator. To calibrate a complete rev, I measure the steps by starting the > count on the 3rd turn ans stopping the count on the 103rd turn, which gives > me a scale*100. Shift the decimal point 2 places left this becomes the scale > for the axis in the .ini file. All this math in linuxcnc is floating point > so I can ask it for 33.333 degrees and it will run to what it thinks is > 33.333 degrees. This stepscale: > STEPSCALE = 22.222 = 1 degree > So one count is about 1/22.222 degrees, probably less than the > backlash in the rvs39 worm, a pretty cheap worm. > > Currently to make one of my maple vise screws, starting at 0 degrees its > around 60,000 degrees it turns for around 400 mm of screw that y travels. > Then I lift the tool, turn it another 180 degrees, re lower the tool and > bring y back to zero and b=180. Makes a perfect two start buttress thread. > The B is turning, in perfect sync with the Y motion, at something in the 300 > to 400 rpm range. That 3NM motor is heating but not dangerously so. > > There is no reason you couldn't lay it down to make a C drive, and > simultaneously drive X Z & C to carve an impeller in a quite serviceable > scroll. > > The versatility of the closed loop stepper/servo, which does EXACTLY what the > TP tells it to do, without a PID in the path, is amazing. I have them rigged > to e-stop linuxcnc in about a millisecond if they make an error, like losing > a step. Tested till the cows come home, has yet to happen working a job. I > haven't hobbed any gears, but it certainly seems accurate enough to do it. > >> Suggestions? >> Thanks >> John >> ___ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> . > > Cheers, Gene Heskett, CET. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Sudo spirals using line segments of arbitrary length are very simple with polar coordinates. Here is a small g-code with anl o-sub that make one: g20 g64 g90 s3400 m3 g0 z1 g0 x2 y0 g1 z-.1 f24 o100 repeat [800] g91 g1 @-.0025 ^4.5 o100 endrepeat g90 g0 z1 m2 Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -Original Message- From: Chris Albertson Sent: Wednesday, April 10, 2024 4:26 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Carving a spiral [EXTERNAL EMAIL] Be sure links are safe. > On Apr 10, 2024, at 10:44 AM, Ralph Stirling via Emc-users > wrote: > > Use the parametric equation of a spiral and compute it *inside* your > g-code program. > > x(t) = c1 * t * cos(t) + x0 > y(t) = c2 * t * sin(t) + y0 COnceptually that is it. But do you really want to cut afull depth 3mm slot with a 3mm tool in one pass? There is another problem. If you make equal increments of “t” the step size increases over time. The steps are farr too small near the center so you waste time cutting too slowly. You want to move in steps such that the desired arc and the straight line approximation is within some tolerance. This is a hard problem. I tried to solve it myself years ago. My boss suggested a sollution: Advance ’t’ is very tiny steps and co,put the error, if the error is small advance it advance it again, if not drop a point. If you do this each point is just inside the tolerance. It was slow. I decided to make bigger jumps and if i overstepped to backup. A good solution is not something you can program in g-cose and every get it right. Today, any reasonable engineer would simply draw the spiral in CAD and then click “generate path” and the CAD system would output the gcode and it would handle the roughing and finishing cuts and the tool changes and handle the spindle speed and cutting rates. No math or thinking is required. But as a challenge or a student exercise, writing an OPTIMAL solution in pure g-code that cuts the metal at the best rate while keeping tolerances is an interesting problem, not simple at all. Most people would let their CAM system figure this out for them. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
> On Apr 10, 2024, at 10:44 AM, Ralph Stirling via Emc-users > wrote: > > Use the parametric equation of a spiral and compute it *inside* your > g-code program. > > x(t) = c1 * t * cos(t) + x0 > y(t) = c2 * t * sin(t) + y0 COnceptually that is it. But do you really want to cut afull depth 3mm slot with a 3mm tool in one pass? There is another problem. If you make equal increments of “t” the step size increases over time. The steps are farr too small near the center so you waste time cutting too slowly. You want to move in steps such that the desired arc and the straight line approximation is within some tolerance. This is a hard problem. I tried to solve it myself years ago. My boss suggested a sollution: Advance ’t’ is very tiny steps and co,put the error, if the error is small advance it advance it again, if not drop a point. If you do this each point is just inside the tolerance. It was slow. I decided to make bigger jumps and if i overstepped to backup. A good solution is not something you can program in g-cose and every get it right. Today, any reasonable engineer would simply draw the spiral in CAD and then click “generate path” and the CAD system would output the gcode and it would handle the roughing and finishing cuts and the tool changes and handle the spindle speed and cutting rates. No math or thinking is required. But as a challenge or a student exercise, writing an OPTIMAL solution in pure g-code that cuts the metal at the best rate while keeping tolerances is an interesting problem, not simple at all. Most people would let their CAM system figure this out for them. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/10/24 14:09, Sam Sokolik wrote: G33 for the win! forgot that, thanks Sam. sam On Wed, Apr 10, 2024 at 12:31 PM Chris Albertson wrote: Do you even need a rotory table to cut a spiral? On Apr 10, 2024, at 12:09 AM, gene heskett wrote: On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not cartesian. The equation of a spiral on polar coordinates is very simple. Then you evaluate itat many thousands of points and at each point write gcode to “cut to” that point. You would not need the rotary table. Also why think in micro-steps and worm gear rates, you are using LCNC to do the kinematics, Use millimeters. I think this problem shows that in some cases you really can not write the gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more lines of code in the file, especially if you don’t do the cut in one pass. You would nee towrite software to generate the g-code. Or use existing software, a lot of CAD systems will do this for you First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using a screw in the worms output hub as a single prox sensor index pulse generator. To calibrate a complete rev, I measure the steps by starting the count on the 3rd turn ans stopping the count on the 103rd turn, which gives me a scale*100. Shift the decimal point 2 places left this becomes the scale for the axis in the .ini file. All this math in linuxcnc is floating point so I can ask it for 33.333 degrees and it will run to what it thinks is 33.333 degrees. This stepscale: STEPSCALE = 22.222 = 1 degree So one count is about 1/22.222 degrees, probably less than the backlash in the rvs39 worm, a pretty cheap worm. Currently to make one of my maple vise screws, starting at 0 degrees its around 60,000 degrees it turns for around 400 mm of screw that y travels. Then I lift the tool, turn it another 180 degrees, re lower the tool and bring y back to zero and b=180. Makes a perfect two start buttress thread. The B is turning, in perfect sync with the Y motion, at something in the 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. There is no reason you couldn't lay it down to make a C drive, and simultaneously drive X Z & C to carve an impeller in a quite serviceable scroll. The versatility of the closed loop stepper/servo, which does EXACTLY what the TP tells it to do, without a PID in the path, is amazing. I have them rigged to e-stop linuxcnc in about a millisecond if they make an error, like losing a step. Tested till the cows come home, has yet to happen working a job. I haven't hobbed any gears, but it certainly seems accurate enough to do it. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/10/24 13:30, Chris Albertson wrote: Do you even need a rotory table to cut a spiral? Now that you ask, I think the answer is probably no. Take a look at the nurbs command G5.2 where a group of points describes the curve. Then rotate the points about one end in polar/rectangular space. I haven't played with that myself, perhaps Andy has a better way? On Apr 10, 2024, at 12:09 AM, gene heskett wrote: On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not cartesian. The equation of a spiral on polar coordinates is very simple. Then you evaluate itat many thousands of points and at each point write gcode to “cut to” that point.You would not need the rotary table. Also why think in micro-steps and worm gear rates, you are using LCNC to do the kinematics, Use millimeters. I think this problem shows that in some cases you really can not write the gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more lines of code in the file, especially if you don’t do the cut in one pass. You would nee towrite software to generate the g-code. Or use existing software, a lot of CAD systems will do this for you First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using a screw in the worms output hub as a single prox sensor index pulse generator. To calibrate a complete rev, I measure the steps by starting the count on the 3rd turn ans stopping the count on the 103rd turn, which gives me a scale*100. Shift the decimal point 2 places left this becomes the scale for the axis in the .ini file. All this math in linuxcnc is floating point so I can ask it for 33.333 degrees and it will run to what it thinks is 33.333 degrees. This stepscale: STEPSCALE = 22.222 = 1 degree So one count is about 1/22.222 degrees, probably less than the backlash in the rvs39 worm, a pretty cheap worm. Currently to make one of my maple vise screws, starting at 0 degrees its around 60,000 degrees it turns for around 400 mm of screw that y travels. Then I lift the tool, turn it another 180 degrees, re lower the tool and bring y back to zero and b=180. Makes a perfect two start buttress thread. The B is turning, in perfect sync with the Y motion, at something in the 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. There is no reason you couldn't lay it down to make a C drive, and simultaneously drive X Z & C to carve an impeller in a quite serviceable scroll. The versatility of the closed loop stepper/servo, which does EXACTLY what the TP tells it to do, without a PID in the path, is amazing. I have them rigged to e-stop linuxcnc in about a millisecond if they make an error, like losing a step. Tested till the cows come home, has yet to happen working a job. I haven't hobbed any gears, but it certainly seems accurate enough to do it. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/10/24 13:03, John Dammeyer wrote: Hi Gene, Just like I can't get my head around Fusion360 or similar CAD. AlibreCAD has gone downhill since they trashed their relationship with MecSoft which correspondingly trashed AlibreCAM. I'll take a closer look at your approach later today. My approaches subroutine will take a loop as the primary slicer because each piece of the scroll will need to start at the root of that slice but the curved pie slice is wider at the outside. The target is to carve each slice from its apex point but widen the rim so that your 3mm wide fin is all that's left, then advance to the apex of the next pie slice. So the subroutine will start at 6 common points around the central axis, and you wind up with 6 3mm wide fins in the scroll shape. That won't be the most efficient shape but will get you started. To improve the efficiency, that central subroutine will need to be converted to use G4 nurbs to describe the spiral path. But that's for next week. And I expect Andy might have some better ideas on the nurbs points. I have a good idea what they can do but zip about the math involved. Flow thru a venturi etc type math. Thanks John -Original Message- From: gene heskett [mailto:ghesk...@shentel.net] Sent: April 10, 2024 3:42 AM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Carving a spiral On 4/10/24 03:37, John Dammeyer wrote: Hi Marcus, Here's the problem. My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y motion. I looked at alibre, could not get my Iowa farm kid head around it. Far easier for me to write my own gcode. In linuxcnc, you can trade the axis names around to fit your hdwe. How far can you tilt your Z? Mine can do a full 90, aka lay the spindle horizontal. Either way IIRC. I can then use X as X, A as A, and a single straight line move to carve the spiral using Z while A is turning N degrees to carve the spiral. So the gcode then becomes a subroutine to do that, and a 2nd loop routine to handle the start of the spiral and possibly a master outer loop to do any incremental cuts to get to the depth needed. Maybe 80 LOC total. If your head cannot tilt that far, then you''l have to cobble up a C, facing up which I CAN do but its a 90/1 drive and will restrict the speed as It can't turn fast enough. Also has a std stepper motor, push its speed and it stalls. Someday I'll put a good motor on it. A Warning though, most of the combo gizmos they sell for $300 or so on ebay are belt drive and no-where near strong enough for this. I did use my 90/1 as A when making my tap hats. Used it to drill & tap the 4 grub screw holes. I setup workstations on the length of the go704's table, put a piece of brass rod in the spindle, drilled the hole for the tap, move the brass to a clamp, drilled and tapped for a locking to an r8 collet screw hole, moved the brass to the A chuck and drilled and tapped all 4 grub screws. All in the same gcode file with pauses and automatic tlo offset corrections as the drills were different lengths. Made a regular production line out of it, took longer moving the brass around than the total run time for the machine. If I tell it to use my 4th axis it's like the video you posted. Designed for creating a spiral on something horizontal to say the X axis. I think I'd have to buy the 5th axis capability in order to be able to have the rotary table turn while the cutter moves in the X direction as the spiral is created. So if I wanted to move the rotary table N degrees while moving X a spiral would also be created. I guess I'm having trouble figuring out the math for the G-Code. It just one command with prelimiinary. in your case position incut at N degrees John -Original Message- From: marcus.bow...@visible.eclipse.co.uk [mailto:marcus.bow...@visible.eclipse.co.uk] Sent: April 10, 2024 12:00 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Carving a spiral As I recall, someone on this list posted a note or a link about how to create a fusee for a clock (essentially a tapered spiral, running from large diameter to smaller diameter while spiralling - rather like a tapered woodscrew thread). Is a constant-diameter version of that what you had in mind? https://www.youtube.com/watch?v=KAAajypWQyw Sadly, I can't remember who contributed that note on this list. I do think there may be a routine somewhere in the LinuxCNC electronic resources. Marcus On 2024-04-10 06:55, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Wit
Re: [Emc-users] Carving a spiral
On Wed, 10 Apr 2024 at 19:11, Sam Sokolik wrote: G33 for the win! Not a silly idea. You could arrange for an encoder to be rotated by the rotary table any way that was convenient, then set that up as as the "spindle" input into LinuxCNC. Then you could simply wind the rotary table by hand. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Use the parametric equation of a spiral and compute it *inside* your g-code program. x(t) = c1 * t * cos(t) + x0 y(t) = c2 * t * sin(t) + y0 Choose as fine a step as you like for t and make a while loop to generate the x and y values and do G1 moves. See https://www.math.fsu.edu/~cstover/teaching/fa16_2312/handouts/parametric/ParamGraphs.pdf for example (p. 2 and 3). -- Ralph From: Chris Albertson [albertson.ch...@gmail.com] Sent: Wednesday, April 10, 2024 10:28 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Carving a spiral CAUTION: This email originated from outside the Walla Walla University email system. Do you even need a rotory table to cut a spiral? > On Apr 10, 2024, at 12:09 AM, gene heskett wrote: > > On 4/10/24 01:57, John Dammeyer wrote: >> A friend and I have been discussing exactly how to write the G-Code to >> create a spiral scroll. >> His rotary table 90:1 reduction with a 1600 micro-step motor could be set up >> to move N steps for each step of the X axis to create the spiral. But that >> approach seems clumsy. >> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. >> Without using G2 or G3 it's really just a triangle isn't it? Move rotary >> table distance A and move X axis distance A'. Do it in small enough >> increments and you get a spiral. But I feel like I'm missing something >> really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not cartesian. The equation of a spiral on polar coordinates is very simple. Then you evaluate itat many thousands of points and at each point write gcode to “cut to” that point.You would not need the rotary table. Also why think in micro-steps and worm gear rates, you are using LCNC to do the kinematics, Use millimeters. I think this problem shows that in some cases you really can not write the gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more lines of code in the file, especially if you don’t do the cut in one pass. You would nee towrite software to generate the g-code. Or use existing software, a lot of CAD systems will do this for you > First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM > 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using > a screw in the worms output hub as a single prox sensor index pulse > generator. To calibrate a complete rev, I measure the steps by starting the > count on the 3rd turn ans stopping the count on the 103rd turn, which gives > me a scale*100. Shift the decimal point 2 places left this becomes the scale > for the axis in the .ini file. All this math in linuxcnc is floating point > so I can ask it for 33.333 degrees and it will run to what it thinks is > 33.333 degrees. This stepscale: > STEPSCALE = 22.222 = 1 degree > So one count is about 1/22.222 degrees, probably less than the > backlash in the rvs39 worm, a pretty cheap worm. > > Currently to make one of my maple vise screws, starting at 0 degrees its > around 60,000 degrees it turns for around 400 mm of screw that y travels. > Then I lift the tool, turn it another 180 degrees, re lower the tool and > bring y back to zero and b=180. Makes a perfect two start buttress thread. > The B is turning, in perfect sync with the Y motion, at something in the 300 > to 400 rpm range. That 3NM motor is heating but not dangerously so. > > There is no reason you couldn't lay it down to make a C drive, and > simultaneously drive X Z & C to carve an impeller in a quite serviceable > scroll. > > The versatility of the closed loop stepper/servo, which does EXACTLY what the > TP tells it to do, without a PID in the path, is amazing. I have them rigged > to e-stop linuxcnc in about a millisecond if they make an error, like losing > a step. Tested till the cows come home, has yet to happen working a job. I > haven't hobbed any gears, but it certainly seems accurate enough to do it. > >> Suggestions? >> Thanks >> John >> ___ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> . > > Cheers, Gene Heskett, CET. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > ___ > Emc-users mail
Re: [Emc-users] Carving a spiral
G33 for the win! sam On Wed, Apr 10, 2024 at 12:31 PM Chris Albertson wrote: > Do you even need a rotory table to cut a spiral? > > > On Apr 10, 2024, at 12:09 AM, gene heskett wrote: > > > > On 4/10/24 01:57, John Dammeyer wrote: > >> A friend and I have been discussing exactly how to write the G-Code to > >> create a spiral scroll. > >> His rotary table 90:1 reduction with a 1600 micro-step motor could be > set up > >> to move N steps for each step of the X axis to create the spiral. But > that > >> approach seems clumsy. > >> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. > >> Without using G2 or G3 it's really just a triangle isn't it? Move > rotary > >> table distance A and move X axis distance A'. Do it in small enough > >> increments and you get a spiral. But I feel like I'm missing something > >> really simple. > > Do you need a rotary table to cut a spiral? It is just a series of > locations in (x,y). OK, if you wanted to use only (say) the X and A axis > then you should use polar coordinates, not cartesian. The equation of a > spiral on polar coordinates is very simple. Then you evaluate itat many > thousands of points and at each point write gcode to “cut to” that point. > You would not need the rotary table. > > Also why think in micro-steps and worm gear rates, you are using LCNC to > do the kinematics, Use millimeters. > > I think this problem shows that in some cases you really can not write the > gcode by hand. FOr continous curves in (x,y) there might be 100,000 or > more lines of code in the file, especially if you don’t do the cut in one > pass. You would nee towrite software to generate the g-code. Or use > existing software, a lot of CAD systems will do this for you > > > > First, a 90/1 is quite high. I have two rotary's, both consisting of a > 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. > Using a screw in the worms output hub as a single prox sensor index pulse > generator. To calibrate a complete rev, I measure the steps by starting the > count on the 3rd turn ans stopping the count on the 103rd turn, which gives > me a scale*100. Shift the decimal point 2 places left this becomes the > scale for the axis in the .ini file. All this math in linuxcnc is floating > point so I can ask it for 33.333 degrees and it will run to what it thinks > is 33.333 degrees. This stepscale: > > STEPSCALE = 22.222 = 1 degree > > So one count is about 1/22.222 degrees, probably less than the > backlash in the rvs39 worm, a pretty cheap worm. > > > > Currently to make one of my maple vise screws, starting at 0 degrees its > around 60,000 degrees it turns for around 400 mm of screw that y travels. > Then I lift the tool, turn it another 180 degrees, re lower the tool and > bring y back to zero and b=180. Makes a perfect two start buttress thread. > The B is turning, in perfect sync with the Y motion, at something in the > 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. > > > > There is no reason you couldn't lay it down to make a C drive, and > simultaneously drive X Z & C to carve an impeller in a quite serviceable > scroll. > > > > The versatility of the closed loop stepper/servo, which does EXACTLY > what the TP tells it to do, without a PID in the path, is amazing. I have > them rigged to e-stop linuxcnc in about a millisecond if they make an > error, like losing a step. Tested till the cows come home, has yet to > happen working a job. I haven't hobbed any gears, but it certainly seems > accurate enough to do it. > > > >> Suggestions? > >> Thanks > >> John > >> ___ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > >> . > > > > Cheers, Gene Heskett, CET. > > -- > > "There are four boxes to be used in defense of liberty: > > soap, ballot, jury, and ammo. Please use in that order." > > -Ed Howdershelt (Author, 1940) > > If we desire respect for the law, we must first make the law respectable. > > - Louis D. Brandeis > > > > > > > > ___ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Do you even need a rotory table to cut a spiral? > On Apr 10, 2024, at 12:09 AM, gene heskett wrote: > > On 4/10/24 01:57, John Dammeyer wrote: >> A friend and I have been discussing exactly how to write the G-Code to >> create a spiral scroll. >> His rotary table 90:1 reduction with a 1600 micro-step motor could be set up >> to move N steps for each step of the X axis to create the spiral. But that >> approach seems clumsy. >> Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. >> Without using G2 or G3 it's really just a triangle isn't it? Move rotary >> table distance A and move X axis distance A'. Do it in small enough >> increments and you get a spiral. But I feel like I'm missing something >> really simple. Do you need a rotary table to cut a spiral? It is just a series of locations in (x,y). OK, if you wanted to use only (say) the X and A axis then you should use polar coordinates, not cartesian. The equation of a spiral on polar coordinates is very simple. Then you evaluate itat many thousands of points and at each point write gcode to “cut to” that point.You would not need the rotary table. Also why think in micro-steps and worm gear rates, you are using LCNC to do the kinematics, Use millimeters. I think this problem shows that in some cases you really can not write the gcode by hand. FOr continous curves in (x,y) there might be 100,000 or more lines of code in the file, especially if you don’t do the cut in one pass. You would nee towrite software to generate the g-code. Or use existing software, a lot of CAD systems will do this for you > First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM > 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using > a screw in the worms output hub as a single prox sensor index pulse > generator. To calibrate a complete rev, I measure the steps by starting the > count on the 3rd turn ans stopping the count on the 103rd turn, which gives > me a scale*100. Shift the decimal point 2 places left this becomes the scale > for the axis in the .ini file. All this math in linuxcnc is floating point > so I can ask it for 33.333 degrees and it will run to what it thinks is > 33.333 degrees. This stepscale: > STEPSCALE = 22.222 = 1 degree > So one count is about 1/22.222 degrees, probably less than the > backlash in the rvs39 worm, a pretty cheap worm. > > Currently to make one of my maple vise screws, starting at 0 degrees its > around 60,000 degrees it turns for around 400 mm of screw that y travels. > Then I lift the tool, turn it another 180 degrees, re lower the tool and > bring y back to zero and b=180. Makes a perfect two start buttress thread. > The B is turning, in perfect sync with the Y motion, at something in the 300 > to 400 rpm range. That 3NM motor is heating but not dangerously so. > > There is no reason you couldn't lay it down to make a C drive, and > simultaneously drive X Z & C to carve an impeller in a quite serviceable > scroll. > > The versatility of the closed loop stepper/servo, which does EXACTLY what the > TP tells it to do, without a PID in the path, is amazing. I have them rigged > to e-stop linuxcnc in about a millisecond if they make an error, like losing > a step. Tested till the cows come home, has yet to happen working a job. I > haven't hobbed any gears, but it certainly seems accurate enough to do it. > >> Suggestions? >> Thanks >> John >> ___ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> . > > Cheers, Gene Heskett, CET. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On Wed, 10 Apr 2024 at 17:30, Alan Condit via Emc-users < emc-users@lists.sourceforge.net> wrote: > > Here us a subroutine I wrote to cut a scroll. > #<_xorigin>, and #<_yorigin> are the center of the scroll. Basically it > changes the radius of the circle every ¼ turn. This is what I was suggesting (but didn't have the time to hack out the code, so thanks) It rather depends how perfect the spiral needs to be. The condition for tangency of two arcs is that their centre points are on a line perpendicular to the arc. If you play about in CAD you can get a feel for what this means for drawing a spiral out of 90 degree arcs. With LinuxCNC you could also try generating a bunch of X,Y points (in Excel for example) and using those to generate a spline. (note, I don't know how well that would work) https://linuxcnc.org/docs/stable/html/gcode/g-code.html#gcode:g5 -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Hi Gene, Just like I can't get my head around Fusion360 or similar CAD. AlibreCAD has gone downhill since they trashed their relationship with MecSoft which correspondingly trashed AlibreCAM. I'll take a closer look at your approach later today. Thanks John > -Original Message- > From: gene heskett [mailto:ghesk...@shentel.net] > Sent: April 10, 2024 3:42 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Carving a spiral > > On 4/10/24 03:37, John Dammeyer wrote: > > Hi Marcus, > > > > Here's the problem. > > > > My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y motion. > > I looked at alibre, could not get my Iowa farm kid head around it. Far > easier for me to write my own gcode. > > In linuxcnc, you can trade the axis names around to fit your hdwe. > > How far can you tilt your Z? Mine can do a full 90, aka lay the spindle > horizontal. Either way IIRC. I can then use X as X, A as A, and a > single straight line move to carve the spiral using Z while A is turning > N degrees to carve the spiral. So the gcode then becomes a subroutine to > do that, and a 2nd loop routine to handle the start of the spiral and > possibly a master outer loop to do any incremental cuts to get to the > depth needed. Maybe 80 LOC total. > > If your head cannot tilt that far, then you''l have to cobble up a C, > facing up which I CAN do but its a 90/1 drive and will restrict the > speed as It can't turn fast enough. Also has a std stepper motor, push > its speed and it stalls. Someday I'll put a good motor on it. > > A Warning though, most of the combo gizmos they sell for $300 or so on > ebay are belt drive and no-where near strong enough for this. I did use > my 90/1 as A when making my tap hats. Used it to drill & tap the 4 grub > screw holes. I setup workstations on the length of the go704's table, > put a piece of brass rod in the spindle, drilled the hole for the tap, > move the brass to a clamp, drilled and tapped for a locking to an r8 > collet screw hole, moved the brass to the A chuck and drilled and tapped > all 4 grub screws. All in the same gcode file with pauses and automatic > tlo offset corrections as the drills were different lengths. Made a > regular production line out of it, took longer moving the brass around > than the total run time for the machine. > > > > > > > > If I tell it to use my 4th axis it's like the video you posted. Designed > > for creating a spiral on something horizontal to say the X axis. > > > > I think I'd have to buy the 5th axis capability in order to be able to have > > the rotary table turn while the cutter moves in the X direction as the > > spiral is created. > > > > > > > > So if I wanted to move the rotary table N degrees while moving X a spiral > > would also be created. I guess I'm having trouble figuring out the math for > > the G-Code. > > It just one command with prelimiinary. in your case position incut at N > degrees > > > > John > > > > > > > > > > > >> -Original Message- > > > >> From: marcus.bow...@visible.eclipse.co.uk > > > >> [mailto:marcus.bow...@visible.eclipse.co.uk] > > > >> Sent: April 10, 2024 12:00 AM > > > >> To: Enhanced Machine Controller (EMC) > > > >> Subject: Re: [Emc-users] Carving a spiral > > > >> > > > >> As I recall, someone on this list posted a note or a link about how to > > > >> create a fusee for a clock (essentially a tapered spiral, running from > > > >> large diameter to smaller diameter while spiralling - rather like a > > > >> tapered woodscrew thread). Is a constant-diameter version of that what > > > >> you had in mind? > > > >> https://www.youtube.com/watch?v=KAAajypWQyw > > > >> > > > >> Sadly, I can't remember who contributed that note on this list. I do > > > >> think there may be a routine somewhere in the LinuxCNC electronic > > > >> resources. > > > >> > > > >> Marcus > > > >> > > > >> > > > >> > > > >> On 2024-04-10 06:55, John Dammeyer wrote: > > > >>> A friend and I have been discussing exactly how to write the G-Code to > > > >>> create a spiral scroll. > > > >>> > > > >>> His rotary table 90:1 reduction with a 1600 micro-step motor could be > > > >>> set up > > > >>> to move N steps for each step of the X axis to create the spiral. But >
Re: [Emc-users] Carving a spiral
Hi Andy, > -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: April 10, 2024 1:54 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Carving a spiral > > On Wed, 10 Apr 2024 at 06:59, John Dammeyer > wrote: > > > > > Without using G2 or G3 it's really just a triangle isn't it? Move rotary > > table distance A and move X axis distance A'. Do it in small enough > > increments and you get a spiral. But I feel like I'm missing something > > really simple. > > > If there is a rotary table, then if he wanted a 10 turn spiral at 6mm pitch: > > G1 F100 A3600 Z60 I can see with your mill how the tool sticks out horizontal so Z moves along the spiral. On my system Z would be depth of the spiral with the rotary table surface horizontal so I believe I'd have to move X. I'll give it a try. > > Should be all that is needed. > > Without a rotary table getting a true spiral is a bit more difficult as the > radius of curvature continually changes, not something that G2 and G3 > support. > I just experimented with polar coordinates, but those only make > straight-line moves between endpoints. > You can get close with arcs that are set up to be tangent to each other. > I'll give that a try. Here's the G-Code for simple G03 Arcs. I'll try a piece of MDF in the router later today and give it a try. G00 G49 G40.1 G17 G80 G50 G90 G20 (2 1/2 Axis Profiling) M6 T2 M03 S2000 G00 Z0.2362 X1.9541 Y-0.2875 G01 Z-0.0394 F6.9 X1.9431 Y-0.0378 F3.4 G17 G03X-0.9159Y1.5406I-1.8761J-0.0197 X-0.8023Y-1.5842I0.9413J-1.5302 X1.6952Y0.1276I0.7916J1.5228 X-0.9227Y1.2481I-1.6261J-0.1807 X-0.4850Y-1.4614I0.9422J-1.2379 X1.4359Y0.2432I0.4780J1.3960 X-0.9295Y0.9243I-1.3645J-0.2907 X-0.2234Y-1.2839I0.9422J-0.9157 X1.1298Y0.4190I0.2223J1.2124 X-0.8954Y0.5843I-1.0567J-0.4575 X0.0243Y-1.0653I0.8997J-0.5796 X0.8182Y0.4888I-0.0176J0.9888 X-0.7397Y0.3786I-0.7459J-0.5226 X0.0233Y-0.8290I0.7429J-0.3755 X0.6610Y0.2987I-0.0186J0.7546 X-0.5013Y0.3238I-0.5887J-0.3349 X-0.0334Y-0.5933I0.5078J-0.3188 X0.4767Y0.1441I0.0350J0.5209 X-0.2823Y0.2285I-0.4046J-0.1840 X-0.0458Y-0.3561I0.2918J-0.2221 X0.2713Y0.0272I0.0449J0.2857 X-0.0860Y0.0982I-0.1995J-0.0694 X-0.0295Y-0.1213I0.0991J-0.0915 X0.0557Y-0.0585I0.0246J0.0558 G00 Z0.2362 M5 M9 M30 John > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is designed > for the especial use of mechanical geniuses, daredevils and lunatics." > � George Fitch, Atlanta Constitution Newspaper, 1912 > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Thanks Alan, I'll take a look at this later today. John > -Original Message- > From: Alan Condit via Emc-users [mailto:emc-users@lists.sourceforge.net] > Sent: April 10, 2024 9:27 AM > To: EMC-Users > Cc: Alan Condit > Subject: Re: [Emc-users] Carving a spiral > > John, > > Here us a subroutine I wrote to cut a scroll. > #<_xorigin>, and #<_yorigin> are the center of the scroll. Basically it > changes > the radius of the circle every � turn. > > > (Subroutine to cut spiral in) > (o call [X] [Y] [Depth] [Stepover] [Radius]) > o sub > (#1 is X center) > (#2 is Y center) > (#3 is Z plunge depth) > (#4 is the stepover amount ) > (#5 is the ending radius ) > (# is the amount to increment start of the next loop) > # = #1 > # = #2 > # = [0-#3]( Depth of cut ) > # = #4 ( Size of stepover ) > # = #5 ( Starting Radius ) > #=[#/4] ( 1/4 of stepover ) > # = # > > G10 L2 P3 X[#<_xorigin>+#] Y[#<_yorigin>+#] Z#<_zorigin> ( > Set the Current Coordinate for G56 ) > # = #<_close_Z>( set Zcut to top of > material ) > G56 ( Select Coordinate system 3 > ) > G00 X0 Y[0-#] Z#<_close_Z> > G01 Z# F#<_xyfeed> > o WHILE [# GT 0] > o IF [[# - #] GE #] > G03 X0 Y[[#-#]*[-1]] R[#-#] > o ENDIF > o IF [[# - [2*#]] GE #] > G03 X[#-[2*#]]Y0 R[#- > [2*#]] > o ENDIF > o IF [[# - [3*#]] GE #] > G03 X0 Y[#-[3*#]]R[#- > [3*#]] > o ENDIF > o IF [[# - #] GE #] > G03 X[[#-#]*[-1]] Y0 R[#-#] > o ENDIF > # = [#-#] > o ENDWHILE > G0 Z#<_close_Z> > G55 > o endsub > > > Alan > > From: "John Dammeyer" <mailto:jo...@autoartisans.com>> > > Subject: [Emc-users] Carving a spiral > > Date: April 10, 2024 at 12:55:36�AM CDT > > To: "Enhanced Machine Controller \(EMC\)" us...@lists.sourceforge.net <mailto:emc-users@lists.sourceforge.net>> > > > > > > A friend and I have been discussing exactly how to write the G-Code to > > create a spiral scroll. > > > > His rotary table 90:1 reduction with a 1600 micro-step motor could be set up > > to move N steps for each step of the X axis to create the spiral. But that > > approach seems clumsy. > > > > Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. > > > > > > > > Without using G2 or G3 it's really just a triangle isn't it? Move rotary > > table distance A and move X axis distance A'. Do it in small enough > > increments and you get a spiral. But I feel like I'm missing something > > really simple. > > > > > > > > Suggestions? > > > > Thanks > > > > John > > > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
John, Here us a subroutine I wrote to cut a scroll. #<_xorigin>, and #<_yorigin> are the center of the scroll. Basically it changes the radius of the circle every ¼ turn. (Subroutine to cut spiral in) (o call [X] [Y] [Depth] [Stepover] [Radius]) o sub (#1 is X center) (#2 is Y center) (#3 is Z plunge depth) (#4 is the stepover amount ) (#5 is the ending radius ) (# is the amount to increment start of the next loop) # = #1 # = #2 # = [0-#3]( Depth of cut ) # = #4 ( Size of stepover ) # = #5 ( Starting Radius ) #=[#/4] ( 1/4 of stepover ) # = # G10 L2 P3 X[#<_xorigin>+#] Y[#<_yorigin>+#] Z#<_zorigin> ( Set the Current Coordinate for G56 ) # = #<_close_Z>( set Zcut to top of material ) G56 ( Select Coordinate system 3 ) G00 X0 Y[0-#] Z#<_close_Z> G01 Z# F#<_xyfeed> o WHILE [# GT 0] o IF [[# - #] GE #] G03 X0 Y[[#-#]*[-1]] R[#-#] o ENDIF o IF [[# - [2*#]] GE #] G03 X[#-[2*#]]Y0 R[#-[2*#]] o ENDIF o IF [[# - [3*#]] GE #] G03 X0 Y[#-[3*#]]R[#-[3*#]] o ENDIF o IF [[# - #] GE #] G03 X[[#-#]*[-1]] Y0 R[#-#] o ENDIF # = [#-#] o ENDWHILE G0 Z#<_close_Z> G55 o endsub Alan > From: "John Dammeyer" mailto:jo...@autoartisans.com>> > Subject: [Emc-users] Carving a spiral > Date: April 10, 2024 at 12:55:36 AM CDT > To: "Enhanced Machine Controller \(EMC\)" <mailto:emc-users@lists.sourceforge.net>> > > > A friend and I have been discussing exactly how to write the G-Code to > create a spiral scroll. > > His rotary table 90:1 reduction with a 1600 micro-step motor could be set up > to move N steps for each step of the X axis to create the spiral. But that > approach seems clumsy. > > Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. > > > > Without using G2 or G3 it's really just a triangle isn't it? Move rotary > table distance A and move X axis distance A'. Do it in small enough > increments and you get a spiral. But I feel like I'm missing something > really simple. > > > > Suggestions? > > Thanks > > John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/10/24 03:37, John Dammeyer wrote: Hi Marcus, Here's the problem. My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y motion. I looked at alibre, could not get my Iowa farm kid head around it. Far easier for me to write my own gcode. In linuxcnc, you can trade the axis names around to fit your hdwe. How far can you tilt your Z? Mine can do a full 90, aka lay the spindle horizontal. Either way IIRC. I can then use X as X, A as A, and a single straight line move to carve the spiral using Z while A is turning N degrees to carve the spiral. So the gcode then becomes a subroutine to do that, and a 2nd loop routine to handle the start of the spiral and possibly a master outer loop to do any incremental cuts to get to the depth needed. Maybe 80 LOC total. If your head cannot tilt that far, then you''l have to cobble up a C, facing up which I CAN do but its a 90/1 drive and will restrict the speed as It can't turn fast enough. Also has a std stepper motor, push its speed and it stalls. Someday I'll put a good motor on it. A Warning though, most of the combo gizmos they sell for $300 or so on ebay are belt drive and no-where near strong enough for this. I did use my 90/1 as A when making my tap hats. Used it to drill & tap the 4 grub screw holes. I setup workstations on the length of the go704's table, put a piece of brass rod in the spindle, drilled the hole for the tap, move the brass to a clamp, drilled and tapped for a locking to an r8 collet screw hole, moved the brass to the A chuck and drilled and tapped all 4 grub screws. All in the same gcode file with pauses and automatic tlo offset corrections as the drills were different lengths. Made a regular production line out of it, took longer moving the brass around than the total run time for the machine. If I tell it to use my 4th axis it's like the video you posted. Designed for creating a spiral on something horizontal to say the X axis. I think I'd have to buy the 5th axis capability in order to be able to have the rotary table turn while the cutter moves in the X direction as the spiral is created. So if I wanted to move the rotary table N degrees while moving X a spiral would also be created. I guess I'm having trouble figuring out the math for the G-Code. It just one command with prelimiinary. in your case position incut at N degrees John -Original Message- From: marcus.bow...@visible.eclipse.co.uk [mailto:marcus.bow...@visible.eclipse.co.uk] Sent: April 10, 2024 12:00 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Carving a spiral As I recall, someone on this list posted a note or a link about how to create a fusee for a clock (essentially a tapered spiral, running from large diameter to smaller diameter while spiralling - rather like a tapered woodscrew thread). Is a constant-diameter version of that what you had in mind? https://www.youtube.com/watch?v=KAAajypWQyw Sadly, I can't remember who contributed that note on this list. I do think there may be a routine somewhere in the LinuxCNC electronic resources. Marcus On 2024-04-10 06:55, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On Wed, 10 Apr 2024 at 06:59, John Dammeyer wrote: > > Without using G2 or G3 it's really just a triangle isn't it? Move rotary > table distance A and move X axis distance A'. Do it in small enough > increments and you get a spiral. But I feel like I'm missing something > really simple. If there is a rotary table, then if he wanted a 10 turn spiral at 6mm pitch: G1 F100 A3600 Z60 Should be all that is needed. Without a rotary table getting a true spiral is a bit more difficult as the radius of curvature continually changes, not something that G2 and G3 support. I just experimented with polar coordinates, but those only make straight-line moves between endpoints. You can get close with arcs that are set up to be tangent to each other. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
Hi Marcus, Here's the problem. My Alibre CAD/Cam can produce a spiral slot in a disk using X and Y motion. If I tell it to use my 4th axis it's like the video you posted. Designed for creating a spiral on something horizontal to say the X axis. I think I'd have to buy the 5th axis capability in order to be able to have the rotary table turn while the cutter moves in the X direction as the spiral is created. So if I wanted to move the rotary table N degrees while moving X a spiral would also be created. I guess I'm having trouble figuring out the math for the G-Code. John > -Original Message- > From: marcus.bow...@visible.eclipse.co.uk > [mailto:marcus.bow...@visible.eclipse.co.uk] > Sent: April 10, 2024 12:00 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Carving a spiral > > As I recall, someone on this list posted a note or a link about how to > create a fusee for a clock (essentially a tapered spiral, running from > large diameter to smaller diameter while spiralling - rather like a > tapered woodscrew thread). Is a constant-diameter version of that what > you had in mind? > https://www.youtube.com/watch?v=KAAajypWQyw > > Sadly, I can't remember who contributed that note on this list. I do > think there may be a routine somewhere in the LinuxCNC electronic > resources. > > Marcus > > > > On 2024-04-10 06:55, John Dammeyer wrote: > > A friend and I have been discussing exactly how to write the G-Code to > > create a spiral scroll. > > > > His rotary table 90:1 reduction with a 1600 micro-step motor could be > > set up > > to move N steps for each step of the X axis to create the spiral. But > > that > > approach seems clumsy. > > > > Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. > > > > > > > > Without using G2 or G3 it's really just a triangle isn't it? Move > > rotary > > table distance A and move X axis distance A'. Do it in small enough > > increments and you get a spiral. But I feel like I'm missing something > > really simple. > > > > > > > > Suggestions? > > > > Thanks > > > > John > > > > > > > > > > ___ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
As I recall, someone on this list posted a note or a link about how to create a fusee for a clock (essentially a tapered spiral, running from large diameter to smaller diameter while spiralling - rather like a tapered woodscrew thread). Is a constant-diameter version of that what you had in mind? https://www.youtube.com/watch?v=KAAajypWQyw Sadly, I can't remember who contributed that note on this list. I do think there may be a routine somewhere in the LinuxCNC electronic resources. Marcus On 2024-04-10 06:55, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Carving a spiral
On 4/10/24 01:57, John Dammeyer wrote: A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. First, a 90/1 is quite high. I have two rotary's, both consisting of a 3NM 3phase stepper/servo I made by combining the 3NM motor with a 5/1 worm. Using a screw in the worms output hub as a single prox sensor index pulse generator. To calibrate a complete rev, I measure the steps by starting the count on the 3rd turn ans stopping the count on the 103rd turn, which gives me a scale*100. Shift the decimal point 2 places left this becomes the scale for the axis in the .ini file. All this math in linuxcnc is floating point so I can ask it for 33.333 degrees and it will run to what it thinks is 33.333 degrees. This stepscale: STEPSCALE = 22.222 = 1 degree So one count is about 1/22.222 degrees, probably less than the backlash in the rvs39 worm, a pretty cheap worm. Currently to make one of my maple vise screws, starting at 0 degrees its around 60,000 degrees it turns for around 400 mm of screw that y travels. Then I lift the tool, turn it another 180 degrees, re lower the tool and bring y back to zero and b=180. Makes a perfect two start buttress thread. The B is turning, in perfect sync with the Y motion, at something in the 300 to 400 rpm range. That 3NM motor is heating but not dangerously so. There is no reason you couldn't lay it down to make a C drive, and simultaneously drive X Z & C to carve an impeller in a quite serviceable scroll. The versatility of the closed loop stepper/servo, which does EXACTLY what the TP tells it to do, without a PID in the path, is amazing. I have them rigged to e-stop linuxcnc in about a millisecond if they make an error, like losing a step. Tested till the cows come home, has yet to happen working a job. I haven't hobbed any gears, but it certainly seems accurate enough to do it. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users . Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Carving a spiral
A friend and I have been discussing exactly how to write the G-Code to create a spiral scroll. His rotary table 90:1 reduction with a 1600 micro-step motor could be set up to move N steps for each step of the X axis to create the spiral. But that approach seems clumsy. Say I wanted to cut a scroll with a 6mm pitch using a 3mm cutter. Without using G2 or G3 it's really just a triangle isn't it? Move rotary table distance A and move X axis distance A'. Do it in small enough increments and you get a spiral. But I feel like I'm missing something really simple. Suggestions? Thanks John ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
