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 > > > >>> 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 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
