I always thought that the small tools used for PCB work (the ones with the colored beads on the shaft) were made so that the back of the bead is a reference distance to the tip of the tool. Then you could change the tool, push the bead up against the collett, tighten to a specific torque, and go.
Ray M. On Sun, Mar 18, 2012 at 6:12 PM, gene heskett <ghesk...@wdtv.com> wrote: > On Sunday, March 18, 2012 09:10:26 PM gene heskett did opine: > > > On Sunday, March 18, 2012 10:56:07 AM Michael Haberler did opine: > > > Am 18.03.2012 um 13:36 schrieb Tony Zampini: > > > > > > ... > > > > > > > On a more general note, being able to "touch off after a tool > > > > change" seems to me to be a necessary function for any and every > > > > milling operation. Why doesn't EMC2 have this feature built-in? Or, > > > > to put it another way, how are users of EMC2 currently determining > > > > the new z offset after changing tools, assuming they don't use a > > > > probing feature? Just curious. > > > > See below. > > > > > please see the example in > > > http://git.linuxcnc.org/gitweb?p=emc2.git;a=tree;f=configs/sim/remap/m > > > an > > > ual-toolchange-with-tool-length-switch;h=8c716f10d20a9f0722de83dda3fb > > > 393 087d94270;hb=10d8caf753ab0269f882d83b59a6c76e2e3ae28d > > > > > > this can easily be adapted to other forms of touchoff > > > > > > -m > > > > I am not aware to a method that doesn't at some point make use of the > > G38.2 function, which means there MUST be a probe of the tool. In my > > case, doing pcb work using eagle & pcb2gcode, I wrote some routines > > that assume the probing pin is connected to the pcb itself. In my > > case, the use of the routines requires that calls to the probe function > > be manually edited into the pcb-gcode output to command a move to a > > location that clears the work space for the tool change, and after each > > tool change call the subroutine to establish the offset. > > > > As I tend to run with rather leasurely accelerations, my probes are done > > relatively slowly so the tool doesn't overshoot and mark up the > > workpiece, so each probe adds about a minute to the production time. > > > > I also added a bit of a fudge factor so the 'etching' depth can be > > controlled without having to rerun pcb-gcode and then reinstall this > > stuff by editing in everything all over again. > > > > At my web page in the sig, add /Genes-os9-stf/eagle to the path and you > > can download the 3 files I use. > > > > tedautoz.ngc (tOPeTCHdRILL.ngc) > > bedautoz.ngc (bOTTOMeTCHdRILL.ngc) > > tholefinder.ngc > > PCB-Pallat.JPG > > > > tholefnder.ngc is written to use a short piece of tubing let into the > > pallet that holds the pcb for etching, and the offsets it develops as it > > runs set the left-right offsets in G55 and G56 modes so the top etch, > > top drill, matches up with the bottom etch and bottom drill files. PCB- > > Pallat.JPG shows fuzzily, what my pallet for that first board looks > > like. The grayer area in the center has been relieved another 25 thou > > so any machining burrs left from the etching and drilling of the first > > side do not prop the board up and mess up the bottom side by etching > > too deeply. > > > > tholefinder.ngc will of course need editing so that what it discovers > > will work for the pcb carrying pallet you'll need to make. I made mine > > from some 1/2" micarta I bought a couple slabs of from Highland > > Hardware in Hotlanta, intending to make zero clearance inserts for my > > BT-3000 Ryobi table saw, something that saw is very badly in need of > > since the plastic casting they sell comes out of the box sitting 50 > > thou too low all over, and over .1" low at the top center of the blade. > > I made 2 zero clearance inserts, and haven't damaged the first one > > yet. Piece of crap factory plastic I won't every buy again. The > > micarta works great. > > > > Cheers, Gene > > I forgot to mention that the pix of the pcb pallet doesn't show the > machined fin on the bottom that fits the T nut slots of my mills table in > order to maintain x alignment when its removed & remounted on the mills > table. > > 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) > My web page: <http://coyoteden.dyndns-free.com:85/gene> > You can't go home again, unless you set $HOME. > > > ------------------------------------------------------------------------------ > This SF email is sponsosred by: > Try Windows Azure free for 90 days Click Here > http://p.sf.net/sfu/sfd2d-msazure > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
