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
