On Saturday, April 23, 2011 10:05:00 AM Dave did opine: > On 4/23/2011 6:57 AM, Mark Wendt (Contractor) wrote: > > On 4/22/2011 5:26 PM, Robert Pabon wrote: > >> Man my head is starting to spin! No wonder people just go with > >> steppers and call it a day. Maybe my vision is clouded by ignorance > >> but it doesn't seem like it should be that hard to pick up a > >> brushless DC motor, a suitable amp and make it work. Obviously it > >> would be easier to just buy a sorted motor/driver, but then it would > >> be easier to buy a sorted CNC machine as well. > >> > >> So getting back to the motor amp combination for a second someone > >> have a look at hese for a minute and tell me what you think. > >> > >> This is the motor I am using: > >> > >> http://www.servodynamics.com/Drawing/23S-IE.pdf > >> > >> I am using the IG23CS-64-IE2000-S > >> > >> Servo dynamics recommends the 1224-BLS driver for this motor. The > >> 1224BL is the comparable amp: > >> > >> http://www.servodynamics.com/Specs/1224bl_spec.pdf > >> > >> And here are the amps I was looking at using: > >> > >> http://www.a-m-c.com/download/datasheet/bd30a8.pdf > >> > >> Servo dynamics says I am fine driving with either sinusoidal or > >> trapezoidal. The AMC is trapezoidal. Obviously need to add a filter > >> card, but otherwise it looks to be in the ballpark. Opinions? > > There must be something wrong with my FF4.x setup, I cannot get any of these pdfs to download or display. Is anyone else have problems?
> > Okay, I'm getting a bit overwhelmed here too. I'm currently using > > steppers on my saw beveler, but have future thoughts of upgrading to a > > servo based system. So, if what Robert shows as necessary, for one > > axis I'd need a servo, an amp, a driver, a bunch of cards for the pc > > end of the affair, an O scope, tons of other test equipment... > > > > Have I left anything out? ;-) > > > > I'm really beginning to wonder if it's worth the expense. > > > > Mark > > Not necessarily. For instance both the Teco and the Automation > Direct servo drives (and many other packaged systems) also accept step > and direction input or analog velocity control. While not as > desirable, step and direction to those servos does work. > > So you could literally disconnect your Gecko or other step and direction > stepper drive, connect a servo drive via step and direction and go after > setting the drive up with its own commissioning software ( not > difficult) be up and running. > If you are going to buy a BLDC motor and match it up with another > companies drive, that can be a chore. > > Using a packaged motor/drive eliminates the work of matching up the > drive and the motor so you are left with tuning the loops in EMC2 to > control the drives via analog control. > > Dave In your situation Mark, as long as the steppers can run the saws fast enough they don't burn (unless they are terminally dull or loaded up with resins from the bamboo), I do not think I would embark on this journey. Even then, if I needed more speed for mine, the only path I would take is more voltage, up to 80 for gecko drives, which could probably run my mill about 2.5x faster as I now run 10-15 ipm when cutting wood. But in my latest genuinely rube goldberg setup, I can carve a 1" long tenon 3/8" thick by 1.25" long on the end of a 1x2 white ash stick with about a minutes actual runtime on the die grinder. Probably 2 minutes to check and adjust the homes for the individual stick before I tap the R button. I need to make a stop to preset the end of the stick that then swings out of the way, and pay more attention to the milling of the sticks to remove that part of the wasted time. I lost my chance to get a G0704 from Grizzly, it is now gone from the catalog so I am back to living with this rig. One problem with that tenon, my current 1/4" 2 flute upcut solid carbide bit is leaving a .004" high shoulder for about 1/16" away from the tenon, which has to be carved away by hand else the joint won't close fully. It also limits me to a 1" tenon unless I write the code for multiple passes to get a greater length. Neither of which is a huge problem. I ordered some more bits, but the flutes are shorter, so I'll have to redo the code anyway. That will likely take care of the micro-shoulder the Bosch router bit is leaving now too. Shrug. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) <http://tinyurl.com/ddg5bz> <http://www.cantrip.org/gatto.html> I don't know WHY I said that ... I think it came from the FILLINGS in my rear molars ... ------------------------------------------------------------------------------ Fulfilling the Lean Software Promise Lean software platforms are now widely adopted and the benefits have been demonstrated beyond question. Learn why your peers are replacing JEE containers with lightweight application servers - and what you can gain from the move. http://p.sf.net/sfu/vmware-sfemails _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
