On Wednesday 17 March 2010, Slavko Kocjancic wrote: >Gene Heskett pravi: >> On Tuesday 16 March 2010, Jon Elson wrote: >>> Slavko Kocjancic wrote: >>>> Somewhere somebody write that 90% users have ATC. >>> >>> Maybe 90% of commercial CNC machining centers have ATC, I SERIOUSLY >>> doubt 90% of EMC2 users have it. >>> Even the monster EMC2-controlled machines at MPM in Wichita don't have >>> an ATC. >>> (The Mazak at Cardinal Engineering did have a working ATC, however, so >>> it CAN be done with EMC2, just that there are a LOT of machines out >>> there that do NOT have an ATC.) >>> >>> Jon >> >> Neither does mine Jon, but AIUI, this isn't rocket science although it >> might need a little rocket fuel. ;-) Or a round tuit, that would be >> helpful. >> >> BTW I am still looking for a pair of (front and back) round tUIt patterns >> I can scale to about a 50 cent piece size. I've been promising a friend >> I was gonna make a small bag of them at some point. I already have a >> couple sticks of alu for them. >> >> Sticking a piece of pcb material, with the copper still on it, to a >> little used corner of the table shouldn't take more than something to >> clean the table down to bare metal so the superglue would bond well, and >> a tube of superglue. Solder the sense wire to a pulled up spare port >> pin, and a short jog to that location & a creep down till the port pin >> goes low, _should_ make an el-cheapo switch. The only fly I could see is >> that since the ground would assume to be through the spindle bearings, >> and they run on an oil film, it might not be too bad an idea to have a >> ground (wired also) spring against the tool shank or the bottom of the >> collet to assure the tool does have a good ground. >> >> I don't see any reason that sub thousandth accuracy could not be obtained >> if the copper film on the pcb is kept reasonably clean. Spindle stopped >> of course. ;-) > >That's work but have drawback. >If you use 0.4mm drill and have little "to high" feedrate then this is >recipy to broke that drill. 20mm/min is to fast in my case. As drill >touch plate then machine need to decelerate to 0 and this give extra 0.1 >mm downfeed just enought to broke drill. If you use bigger dril that's >usaly not the problem. For that reason the probe can be made to alow >slight movment. Can be done with some plastic pipe with 3 metal pin in >radius 120degre apart and metalic plate pushed from bottom to top. Can >be made from PCB material and can be made traces with exacto knife. And >then just little spring or even rubber to push that up. And this alow >much faster feedrates too.
True, and all good ideas, The main one I see is that the hold down clips or bolts used to establish the true zero point would need to be of some insulating material like nylon. And that also presents a cleanliness puzzle, keeping swarf from getting under the clips or bolt heads and affecting the zero point by holding it falsely low. Has anyone actually found that to be a problem? In my case I never considered a .4mm drill, although I did have a set of numbered drills that went to #72 at the tv station. Used for resizing the hole in a crimped on coax connector pin. I'd bought 1000 bnc connectors for a certain coax cable commonly used, and the pins were drilled about a thou small for the brand of cable we were also buying in 1k' rolls. The drill bit kit was cheaper than fighting with a return policy when the idigits on the phone had NDI what to do to fix it. Since it also came with a pin vice to hold & spin the drill bits with it was easier to pull out the pin and drill it on the spot before crimping it. Probably the reason I got what was an otherwise excellently made & finished connector at about a buck a piece less than the 100's price at Newark et all. A $30 toy drill kit was a small price for the fix in that case, and it got me going on that overdue project the same day. -- 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) Hiroshima '45 Tschernobyl '86 Windows '95 ------------------------------------------------------------------------------ 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
