On Saturday, January 29, 2011 05:31:04 pm Mark Wendt (Contractor) did opine:
> Was cruising through the doccy's today and came across comp_file in the > config ini section, and had seen something thta piqued my interest > whilst perusing the EMC2 section on CNCZone in answer to somebody else's > question about backlash compensation. Chris M, chester88 on CNCZone > said thus: "EMC does simple backlash compensation and sophisticated > mapped compensation (which requires homing to a accurate consistent > point). little bit about it here: Basic Configuration > (http://www.linuxcnc.org/docs/2.4/html/config_ini_config.html#sub:)[AXIS > ]-section." > > > For my own nefarious reasons, I became interested in this, with an idea > popping into my head. For those not familiar with my machine, it's a > two axis (X and Z) saw beveling machine, which cuts tapered triangular > bamboo strips out of rectangular stock in one pass, starting on the thin > end and cutting deeper into the strip to finish on the thick end. > > With that in mind, I use a vacuum hold down to keep the strips in place, > which is 3/4" wide by 60" long. I've been draw filing with a nice > expensive Vixen file and some amateurish scraping, and so far have > gotten most of the surface of the hold-down/bed within .001" - .002" of > my 0,0 point. > > Now, my nefarious reason - I'm realized that a career of hand scraping > is not for me. I've mapped the entire length of the hold-down/bed with > a depth gauge, and know, for every inch of X, the difference between the > current station and the 0 point for the Z axis. For instance, I set my > depth gauge to read 0.000" at X0. At X1, for illustration's sake, lets > say Z is .001", X2 - Z = 0.0005", X3 = .001", and so on and so forth for > the entire length of the hold-down/bed at 1" intervals (had to do this > so I could get this close while filing and scraping). The readings of > the depth gauge are repeatable, so I'm pretty sure the depth gauge is > giving me accurate readings. > > My question is, can comp_file be used to map out those inconsistent > heights in software, so that I don't have to file and scrape anymore? > ;-) > > Mark ISTR where I read that as being an emc capability someplace back in the fog of time, Mark. Screw error mapping I believe it was called. But, so you don't have to, consider that if the saws can be replaced with wide diamond wheels, say like as used in the drill doctor, it seems like it would be possible to cobble up a g-code file to drive your machine and let it do the shaving. If that isn't feasible, maybe the hand chuck of a dremel (its really too darned flexible IMO with its rubber mounted and too short spindle so it would take many, just barely kiss it passes) or maybe a Proxxon, with one of those drill doctor wheels mounted, could be strapped to the carriage for that duty long enough to fine tune the bed. Since a bed replacement would be a major operation, I would not shoot for anything but straight and flat using the carriage supports as the master, and any curves then could be done in the g-code with the knowledge that what you get is not going to need any great amount of hand sanding to get the desired taper in the finished product. OTOH, I imagine you _have_ considered that. In which case ignore my ramblings. :) -- 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> * * * * * THIS TERMINAL IS IN USE * * * * * ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
