On Thursday 16 July 2015 06:51:43 Gene Heskett wrote: > On Tuesday 14 July 2015 07:20:12 Gene Heskett wrote: > > Thinking out loud... > > Encoder mounted, runs, encoder velocity output noisy as hell. As in > 40% or more. > > I'll add it to the halscope trace so I an see if the noise is 1x turn > meaning the disk is eccentric, or 2x turn, meaning backlash is fubar. > > Cyclic noisy, like my toy mills backlash is uneven between axis's. > > In/out positioning seems extra fussy as well. A 5 thou move adjusts > the duty cycle noticably. > > Like the outer edge slots aren't deep enough. I've room enough in the > opto gullets to add 20 thou. > > My method of adjusting backlash maybe needs rethinking, so before I > make another disk by moving the last cutout (which intersects the > outer end of the already cut slot in this code) outward 20 thou, and > possibly use 68 slots so I don't have to bend the optos sideways so > far to get decent quadrature (I have to spread them about 15 thou), I > think I'll try a different method. > > Use a larger test move, say 5 thou, and adjust the backlash setting > until I get exactly a 5 thou move. That might result in a more > consistent slot width cut. > > How do the rest of you go about this thing called backlash > calibration? > > Also deepen the final cuts as the last one left some flashing in about > a dozen slots I had to cut away with a razor blade due to the brass > being warped by the clamping pressure. > > And I might try some of that double stick tape, if I can find some > locally. If I can do the cuts stopping 2 thou above the table, that > should get far enough into the tape and reduce the left over fins I'm > getting by using a piece of 1/4" 5 ply as sacrificial. It crushes too > easily. > > Has anyone broken a bit because it gets clogged with tape glue so it > doesn't toss the cuttings clear? > > That does seem to be a valid concern with a 1/32" inch mill. > > I wonder if a couple hours in my Lyman case polisher might remove any > leftover fins in the slots that I can't see? > > That might be worth a shot too.
Testing the mill, I had to adjust the backlash a bit, but found that the bottom nut of the z drive had worked loose. Tightened it slowly while backing off the top one, until the bottom one was 1/8 turn from broke, I was able to adjust that nook acme screw with the top nut, normally locked by an aeroseal clamp, to less than 1.8 thou of backlash. Hopefully that will hold for a while. I went downtown and found the only roll of double-stick in town that said it was removable, a very thin film with sticky on both sides. 2 strips seem to be doing a great job, and shouldn't muck the accuracy as it does not have the foam center that the permanent rated stuff does. I take it acetone will remove that stuff? I set z=0.000 at .041" above the table, it will dig to -0.038" which should clear the table. Increased the OD of the disk by .020" increased the width of the edge pattern by that same .020" and added one slot. I hope the bit lasts, it threw up a burr I could shave off with a sharp wood chisel on the first pass. After two passes thru the loop I noticed the inside cutout wasn't being done, wrong sign in an if test I had added. 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> ------------------------------------------------------------------------------ Don't Limit Your Business. Reach for the Cloud. GigeNET's Cloud Solutions provide you with the tools and support that you need to offload your IT needs and focus on growing your business. Configured For All Businesses. Start Your Cloud Today. https://www.gigenetcloud.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
