On Monday 01 March 2010, Kent A. Reed wrote: >Sunday, Gene Heskett wrote: >> For motor dampers, there are several designs extant. Mine are big fender >> washers with sheet rubber between them in loose stacks, others have used >> weighted skate wheels and such effectively too. > >I've been avoiding the issue of mid-band resonance on my stepper-fitted >tabletop mill until I get the basics taken care of. > >I like the simplicity of your damping solution compared to some of the >designs I've run across. Did you do any before/after tests to determine >the effectiveness?
Only that I had stall problems at about 7 to 10 ipm without them, and my z can now do 34 ipm if everything is 100%. I have it set for about 24 ipm on all 3 linear axis's, and if its fairly clean, no hiccups. That of course exceeds the spindle power and rpms capability quite handily for a decent cut in steel, and pushes it badly in alu, so most of my work is at slower, burn the friggin bit up speeds. :( I need more spindle power and rpms, and decently active coolant, still looking for a suitable 24 volt air valve I can control through EMC. I made a mister that seems to work well last summer, and now need to control the oil in the air better than just letting it blow. I'm told the stuff is hard on lungs, and at 75, these are a bit old & decrepit, having been insulted with 45 years of my own smoking, and the 2nd hand I get from the missus since I quit nearly 21 years back up the log. The rubber washers were hand cut from sheet stock, having about a 3/8" hole, so they are stretched over the 1/2 diameter center, and the fender washers of course are loose, with the majority of the friction being from the fattened center of the rubber as it stretches around the center post. I can grab the stack, or a single fender washer and turn them easily. You want to be able to run a magic marker line down the edge of the washer stack, run it at a mid-speed from one end to other, stop and see that the fenders washers are no longer in step, they have slipped some in absorbing the resonance of the motors. For a 12" run and back, the magic markers should be well scrambled. My biggest problem is that the steel I made those drums from is old mine shafting (this _is_ WV), and is a good rockwell 60ish for hardness, it played hell with my carbide bits for the 7x12 lathe you saw. FWIW, those slip joint drives on the other end of the motors are made out of the same stuff, picked it all up from a local scrap metals place. Unmarked of course... No rubber spiders, steel on steel and after 5 years, still has very little backlash. Maybe 1 or 2 microsteps of the motors, and whatever its turning, is turning. Or else... ;) >Regards, >Kent Thanks Kent. -- 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) You are false data. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
