Re: [Emc-users] Min spindle encoder resolution for mill rigid tapping?
There is no such thing as instantly there is a delay until an edge is detected, a delay before the software has looked at the current position and direction and a delay before Z starts to follow the reversal, the sum of delays is a strain on the tap, making all numbers less will reduce the strain. I have made a 50 slot wheel for my 5 axis in readiness to try rigid tapping. 200 counts per rev, Z screw is 1mm per rev, that is about .2 thou from the encoding and more for any software delay to Z command. Someone with a .2 pitch screw and 8 slots has a possible error of 6.25 thou before seeing the encoder edge. not something I would try. Dave Caroline -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] looking for recommendations on a benchtop mill
On 11 August 2015 at 02:13, Jon Elson el...@pico-systems.com wrote: For off the shelf machines, I'm pretty sure Novakon, Tormach and Smithy can all deliver machines with LinuxCNC. Also, it seems, RongFu looking at their promo on YouTube. But I can't find a stockist or price. Syil is an option, but I have never even seen one, so can't really reccomend. The price is low, but no computer is included. http://www.syilamerica.com/machine_x4st.php -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] looking for recommendations on a benchtop mill
On 08/10/2015 04:50 PM, Jerry Scharf wrote: Hi, I am looking for a new mill for the company I work for. I am looking for something that I can run with linuxcnc and is reasonably stiff. The new Tormach 770 I'm using now is very tight. Tight enough so far that I forgo lead out moves which I would need on my other machines to prevent a divot as the tool retracts from the workpiece. Tormach's PathPilot software is a version of LinuxCNC. This is for simple prototyping work and would be ideal if it could be used in a manual mode as well as cnc driven. The conversational and probing screens are handy for some things I used to do manually, and faster. There are options for adding a jogging device or manual pulse generator. My manual mill is becoming more of an over-sized drill press. No need for things like tool turrets or anything like that. We are not looking for a coolant system. We would consider new or very well maintained used. I am not looking for a project. A tool changer is an option which, when the time comes, would be fairly easy to add later. Tormach's version of R-8 tooling is faster for manual changes and has repeatable tool lengths so you can change tools without having to touch off on every tool change. The tooling system is compatible with standard R-8, so you can use both if you already have R-8 tooling. A CAT 30 spindle is available. Tormach machines are popular so resale values tend to be higher. I know there are some very high end units that are beyond our means, so I wanted people's opinions on where the price vs performance line really flattens out. With some planning as to which configuration and accessories you need, you can be up and running with a Tormach in a day (more likely hours) after your shipment arrives. http://www.wallacecompany.com/tmp/img_1463-1a.jpg http://www.wallacecompany.com/tmp/img_1464-1a.jpg http://www.wallacecompany.com/tmp/img_1466-1a.jpg http://www.wallacecompany.com/tmp/img_1468-1a.jpg -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Min spindle encoder resolution for mill rigid tapping?
On Tuesday 11 August 2015 02:48:53 Dave Caroline wrote: It also depends on minimum tap size, a tiny tap will be less able to stand any vertical strain due to encoder resolution in thou per encoder edge and there has to be an amount due to the turn around of up to something (a count) plus any delay in the software and servo driver lags (ferror) I haven't broken a tap (yet). Because the lock between spindle and carriage is beyond my weak drive, even a drive failure from spinning the teeth off the lower drive pulley has only resulted in a howling drive as the PID pours on even more coal. So, I kill the spindle power and finish the job by hand using the chuck key as a handle. The carriage dutifully follows my motion applied to the chuck until I can either have the tap free, or in one event, I hand pecked it for about 10 minutes and finished the job, then backed it out of the hole, intact. Where I get in trouble is on a bigger tap that isn't chucked tightly enough to prevent its turning in the drill chuck mounted to the toolpost. That slippage will get it out of time put some strain on things, best to loosen the chuck, back it away, pull it off the QC and use a tap wrench to extract it from the unfinished hole. Rather machine dependent(and its settings) and I doubt anyone can write a general specification. I can't argue that point. Each machine is its own best judge. With a 50 cycle wheel on the lathe, direction reversals are not a problem as they are detected instantly. At what point a lessor count in the wheel would become a problem I don't know. An 8 slot wheel feeding an ABX encoder might work surprisingly well. I wonder if the tap makers have any numbers for machine taps. Dave Caroline On 11/08/2015, Jon Elson el...@pico-systems.com wrote: On 08/10/2015 06:38 PM, David Bagby wrote: Hi, I'm planning a mill conversion to LCNC and I'd like it to be able to do rigid tapping. I figure that this will require an encoder or equivalent) on the spindle. I won't be able to to easily attach a common encoder disc to the spindle, so I will probably have to create an encoder (which appears easier than doing a remote encoder driven via a belt etc). I've looked but not found a spec for the required encoder resolution. Does anyone have advice as to min spindle encoder resolution (ppr) required? Has anyone gotten by with 8 or 12 pulses (32 or 48 quadrature) ? I've been doing it using the 81 tooth bull gear on my Bridgeport 1J head, and that works fine. That comes out to 324 quadrature counts/rev. I'd guess that your counts will likely work OK, too. You can figure out the steps/second the encoder value will show. For instance, at 100 RPM, the spindle will be turning 1.667 RPS, and 32 counts/rev will give 32 * 1.667 = 53.33 increments/second to the encoder value. Most machine controls don't have the bandwidth to keep up with that, and will just average over it. The worst situation would be that this would feed a stairstep position to the PID (assuming a servo Z axis) and that the PID + drive combination would have some resonance at certain frequencies that could be excited by the stairstep. Jon -- ___ 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 -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Min spindle encoder resolution for mill rigid tapping?
It also depends on minimum tap size, a tiny tap will be less able to stand any vertical strain due to encoder resolution in thou per encoder edge and there has to be an amount due to the turn around of up to something (a count) plus any delay in the software and servo driver lags (ferror) Rather machine dependent(and its settings) and I doubt anyone can write a general specification. I wonder if the tap makers have any numbers for machine taps. Dave Caroline On 11/08/2015, Jon Elson el...@pico-systems.com wrote: On 08/10/2015 06:38 PM, David Bagby wrote: Hi, I'm planning a mill conversion to LCNC and I'd like it to be able to do rigid tapping. I figure that this will require an encoder or equivalent) on the spindle. I won't be able to to easily attach a common encoder disc to the spindle, so I will probably have to create an encoder (which appears easier than doing a remote encoder driven via a belt etc). I've looked but not found a spec for the required encoder resolution. Does anyone have advice as to min spindle encoder resolution (ppr) required? Has anyone gotten by with 8 or 12 pulses (32 or 48 quadrature) ? I've been doing it using the 81 tooth bull gear on my Bridgeport 1J head, and that works fine. That comes out to 324 quadrature counts/rev. I'd guess that your counts will likely work OK, too. You can figure out the steps/second the encoder value will show. For instance, at 100 RPM, the spindle will be turning 1.667 RPS, and 32 counts/rev will give 32 * 1.667 = 53.33 increments/second to the encoder value. Most machine controls don't have the bandwidth to keep up with that, and will just average over it. The worst situation would be that this would feed a stairstep position to the PID (assuming a servo Z axis) and that the PID + drive combination would have some resonance at certain frequencies that could be excited by the stairstep. Jon -- ___ 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] Spurious machine state changes, updates
If I remember correctly I heard somewhere stop is not allowed to be a toggle button. Regards Nicklas Karlsson On Tue, 11 Aug 2015 08:06:51 -0400 lloyd wilson llwilso...@rochester.rr.com wrote: I think I've solved the state change conundrum I asked about last week - While watching the debug messages (using 0x11c0 debug setting), a deactivation event occurred, causing a 'emcTaskPlanClose' event, but nothing that indicated the precipitant event. I backed the machine to a previous program point and restarted - bad move; I had picked the wrong restart point and had to e-stop the machine. However, the e-stop generated the same plan close event report - H As I originally reported, there is no HAL pin associated with the machine's active/inactive state - but there is for e-stop (e-stop chain activates a relay, one pole of which goes to emc-enable-in). The relay is a recycled dry contact unit, so there is a potential for noisy connections. After adding a debounce function to the e-stop signal, no further instances of the state change phenomenon have been observed, so it looks like that demon has been exorcised. However, this does raise a question about LCNC's e-stop behavior: at initial startup, we have to manually exit e-stop state via the user panel, but thereafter e-stop state tracks the HAL pin, so a noise spike on e-stop can bump the machine to inactive state and leave no trace (unless there is a debug setting I missed). At the least, such asymmetrical behavior can lead to confusion (see current writer). Given that e-stop is a cataclysmic event, I would think it more appropriate for an e-stop event to latch the machine's state and require a manual reset, as at system startup. Is there a specific rationale for the way e-stop is currently handled? Thanks to all who offered suggestions -ldw -- ___ 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] Min spindle encoder resolution for mill rigid tapping?
On Tuesday 11 August 2015 04:41:16 Dave Caroline wrote: There is no such thing as instantly there is a delay until an edge is detected, a delay before the software has looked at the current position and direction and a delay before Z starts to follow the reversal, the sum of delays is a strain on the tap, making all numbers less will reduce the strain. I have made a 50 slot wheel for my 5 axis in readiness to try rigid tapping. 200 counts per rev, Z screw is 1mm per rev, that is about .2 thou from the encoding and more for any software delay to Z command. A ball Z screw of 1mm/rev? Even my toy lathes 16mm PD z screw is 5mm/rev. Its also geared down from a 425 motor, 2/1. Someone with a .2 pitch screw and 8 slots has a possible error of 6.25 thou before seeing the encoder edge. not something I would try. 8 slots=32 edges for an ABX encoder. So it outputs an update every 11.25 degrees A 1/2-13 USS tap, and an 8 slot encoders best would be a 0.00240384615385 error. Worst case maybe 2x that at the inner turnaround. With the reative lack of rigidity in my carraige, I would try it on scrap the first time. I suspect it would be 100% usable way better than I could do by hand. Thats _If_ I had the drive parts laying there, installed. I have a kit that puts all metal sprockets and backgears in it, but haven't found the round tuit yet. Because my jackshaft, which is a 3/1 reduction from a 1 HP motor already, has a 9mm output shaft, and the new kit is 8mm, I think I will order a lower sprocket with 2x the teeth and a suitably longer XL belt. IMO there's not enough sprocket hub to bore it to 9mm and have it survive, and from the papers, my max revs will be under 1000 in high gear due to the pre-existing 3/1. But that bridge is not yet in sight. I may use the last plastic sprocket to make a jackshaft wih an 8mm output change that out just so I can use this sprocket see if its really too slow. But that will be after I have the GO704 fully calibrated. Dave Caroline -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) Genes Web page http://geneslinuxbox.net:6309/gene -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Spurious machine state changes, updates
I think I've solved the state change conundrum I asked about last week - While watching the debug messages (using 0x11c0 debug setting), a deactivation event occurred, causing a 'emcTaskPlanClose' event, but nothing that indicated the precipitant event. I backed the machine to a previous program point and restarted - bad move; I had picked the wrong restart point and had to e-stop the machine. However, the e-stop generated the same plan close event report - H As I originally reported, there is no HAL pin associated with the machine's active/inactive state - but there is for e-stop (e-stop chain activates a relay, one pole of which goes to emc-enable-in). The relay is a recycled dry contact unit, so there is a potential for noisy connections. After adding a debounce function to the e-stop signal, no further instances of the state change phenomenon have been observed, so it looks like that demon has been exorcised. However, this does raise a question about LCNC's e-stop behavior: at initial startup, we have to manually exit e-stop state via the user panel, but thereafter e-stop state tracks the HAL pin, so a noise spike on e-stop can bump the machine to inactive state and leave no trace (unless there is a debug setting I missed). At the least, such asymmetrical behavior can lead to confusion (see current writer). Given that e-stop is a cataclysmic event, I would think it more appropriate for an e-stop event to latch the machine's state and require a manual reset, as at system startup. Is there a specific rationale for the way e-stop is currently handled? Thanks to all who offered suggestions -ldw -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] LinuxCNC 2.6.9
Seb, Do you have the changelog? Rick On 8/11/2015 10:51 AM, Sebastian Kuzminsky wrote: Good morning folks, a new bugfix release of LinuxCNC is available: 2.6.9. All users of 2.6 are encouraged to upgrade. Highlights in this release are: * improved docs * touchy: Fix Set Tool/Origin defaults on lathes * gmoccapy: several improvements * vismach: work around a bug in mesa * interp: fix the mdi/oword/queuebuster bug Andy found * io: initialize the tool-in-spindle info correctly My thanks to everyone who reported bugs and helped each other on the forums, mailing lists, and IRC, and especially to the people who worked on the code docs for this release: Andy Pugh Chris Radek Jeff Epler John Thornton Moses McKnight Norbert Schechner -- Thanks Rick Lair Superior Roll Turning LLC 399 East Center Street Petersburg MI, 49270 PH: 734-279-1831 FAX: 734-279-1166 www.superiorroll.com -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] LinuxCNC 2.6.9
Good morning folks, a new bugfix release of LinuxCNC is available: 2.6.9. All users of 2.6 are encouraged to upgrade. Highlights in this release are: * improved docs * touchy: Fix Set Tool/Origin defaults on lathes * gmoccapy: several improvements * vismach: work around a bug in mesa * interp: fix the mdi/oword/queuebuster bug Andy found * io: initialize the tool-in-spindle info correctly My thanks to everyone who reported bugs and helped each other on the forums, mailing lists, and IRC, and especially to the people who worked on the code docs for this release: Andy Pugh Chris Radek Jeff Epler John Thornton Moses McKnight Norbert Schechner -- Sebastian Kuzminsky -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] LinuxCNC 2.6.9
The full changelog is the git history, of course, but a digested version is here: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Released_2.6.X On 08/11/2015 08:58 AM, Rick Lair wrote: Seb, Do you have the changelog? Rick On 8/11/2015 10:51 AM, Sebastian Kuzminsky wrote: Good morning folks, a new bugfix release of LinuxCNC is available: 2.6.9. All users of 2.6 are encouraged to upgrade. Highlights in this release are: * improved docs * touchy: Fix Set Tool/Origin defaults on lathes * gmoccapy: several improvements * vismach: work around a bug in mesa * interp: fix the mdi/oword/queuebuster bug Andy found * io: initialize the tool-in-spindle info correctly My thanks to everyone who reported bugs and helped each other on the forums, mailing lists, and IRC, and especially to the people who worked on the code docs for this release: Andy Pugh Chris Radek Jeff Epler John Thornton Moses McKnight Norbert Schechner -- Sebastian Kuzminsky -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Min spindle encoder resolution for mill rigid tapping?
On 08/11/2015 01:48 AM, Dave Caroline wrote: It also depends on minimum tap size, a tiny tap will be less able to stand any vertical strain due to encoder resolution in thou per encoder edge and there has to be an amount due to the turn around of up to something (a count) plus any delay in the software and servo driver lags (ferror) I do 4-40 rigid tapping all the time on my Bridgeport, which does have some spring and backlash in the CNC coupling. I have even done 2-56 with no trouble. Jon -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Min spindle encoder resolution for mill rigid tapping?
Hi folks, Thanks for the inputs. I now understand better what to be thinking about and can continue the planning the conversion. Dave -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] BeagleBone and LinuxCNC for a lathe.
I'm thinking of ordering one of the Probotix Breakout Boards for my Beagle Bone Black. Probotix has a downloadable image of LinuxCNC so getting it up and running shouldn't be an issue. http://www.probotix.com/CNC-CONTROL-SYSTEMS/BREAKOUT-BOARDS/PBX-BB-BeagleBon e-Breakout-Board I've not looked at LinuxCNC for some time but I'm wondering how it does with lathes nowadays. For example if I mount a stepper motor to drive the spindle does LinuxCNC support standard step/dir signals to drive the spindle motor? Thanks John Dammeyer ELS! Nothing else works as well for your Lathe Automation Artisans Inc. http://www.autoartisans.com/ELS/ http://www.autoartisans.com/ELS/ Ph. 1 250 544 4950 -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] BeagleBone and LinuxCNC for a lathe.
On Tue, 2015-08-11 at 23:53 -0400, Gene Heskett wrote: On Tuesday 11 August 2015 21:43:46 John Dammeyer wrote: I'm thinking of ordering one of the Probotix Breakout Boards for my Beagle Bone Black. Probotix has a downloadable image of LinuxCNC so getting it up and running shouldn't be an issue. http://www.probotix.com/CNC-CONTROL-SYSTEMS/BREAKOUT-BOARDS/PBX-BB-Bea gleBon e-Breakout-Board I've not looked at LinuxCNC for some time but I'm wondering how it does with lathes nowadays. For example if I mount a stepper motor to drive the spindle does LinuxCNC support standard step/dir signals to drive the spindle motor? Thanks John Dammeyer I am one who is running a small lathe with LinuxCNC, which it does far better than I can. This subject has come up in the past, and I don't recall anyone saying no it can't be done. Given a big enough motor, I see no huge show stopper in substituting a stepgen for the pwmgen module. But the high speed performance as a spindle motor might not be universally usable. One might have to get creative for a motor/controller source. I have seen pix of someone using the huge stepper motor out of a modern washing machine, which would seem to have the torque, and since its also doing the spin cycle, might have the high speed performance too. But in terms of positional accuracy, those do not have the pole count of a moderm stepper. Someone who has actually done it should pipe up and testify. Searching ebay, the largest motor I can come up with is a nema 42, rated at 4120 oz/in. I believe that I have seen nema 56 motors on ebay in the past, but not tonight. Here is one candidate possibility, but its 3 of them for $900 USD: http://www.ebay.com/itm/big-force-3-nema-42-stepper-motors-4120oz-in-8A-3-drivers-DM2722A-9-8A-12-months-/261930438088?hash=item3cfc454dc8 I note that the driver remembers what microstep it was at in the sequence, even if power cycled, provided it has been stopped for at least 5 seconds. That is not something the smaller drivers like the DM860 does, but I can see where that could be handier than bottled beer. No loss of machine positioning from power cycling the whole machine. Cheers, Gene Heskett hmm, I had some problem with microstepping my hybrid motors, they where changing direction at random and had a small force, so I have set them at full step and the problem went away. I have read that it has something to do with the way the motor is driven in microstepping mode. -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] BeagleBone and LinuxCNC for a lathe.
I am one who is running a small lathe with LinuxCNC, which it does far better than I can. This subject has come up in the past, and I don't recall anyone saying no it can't be done. Given a big enough motor, I see no huge show stopper in substituting a stepgen for the pwmgen module. But the high speed performance as a spindle motor might not be universally usable. Cheers, Gene Heskett Thanks Gene, In this case I'm considering installing it on a Unimat Lathe. The 650 oz-in size 34 motor appears to be large enough compared to the small DC brush motor currently attached. I'd have to step up the RPM in order to get the turning speed currently available. In either case, the question is whether or not LinuxCNC can even create stepping pulses for a spindle or if only PWM is available. John -- ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
