On Sunday 24 June 2018 12:17:22 Gene Heskett wrote: > I have a subroutine that measures tool lengths, used mainly because > the tool.tbl has no entries suitable for measuring or characterizing > taps, but since the shank drill also changes depending on the tap hat > being made, I've used this in a subroutine to give me an offset to be > used in the next operation. > > It looks like this: > g38.2 f160 z-80 (go fast, don't need ultra precision here ) > G92 Z25.0000000 ( adjust this to make all #<_vars> positive ) > ( get tool off contact pad ) > > But if something goes wrong, and I restart from the top with this > offset in effect it can move in the wrong direction and break things. > > I have, at various points after an operation based on this offset, put > in a canceling command that is outside of this subroutine, but with no > exceptions, all vars are global, so the subroutine should not effect > the scope of these changes in the z reference. > > But it seems I am not getting, with a g92.1 or a g92.2, the effect I > want. And the error can be 100mm or more, breaking drill bits etc. > > So what is the approved, cancels it all g92.x command, Yesterday its > first move was supposed to be to z150, room to change tools. It was > sitting at about 0z, having just drilled the shank hole in a new brass > cylinder, and I had lifted it by hand jog enough to pull the drilled > brass slug and had placed it in the rotary tables R8 where the 4 holes > at 90 degree intervals would be bored next. When I hit r, it should > have risen to z150, moved toward the center of the table, then to a > contact pad location to then descend and measure the drill 1/8" for a > 4x.7 tap ending at the above code. > > But instead of rising, it went down at 1700mm/min, pushing the 1/8" > bit right down the axis of the .199 shank bit still sticking up out of > the chuck fixed to the table, and of course breaking that bit when the > spindle came up to drilling speed at the end of that move. So that > first move to z150, intended to get clearance from the forest of jigs > etc sticking up from the table, was totally wrong. > > So, can the g92.1 or G92.2 be over-used, potentially creating this > scenario? The docs don't explicitly say. I'll go back and ascertain > that I am not putzing with the #5211-#5219 stuff as that reads like > disaster making. So a g92.2 should be the correct cancel the offset > command in my mind. And I just found a g92.1. Boom. Bet thats it. > Stay tuned.
It turns out I had two of the g92.1's in there, the first one didn't noticeably hurt, just made a longer run for the g38.2, but the 2nd call to that sub found bad data in #5211-#5219 and boom. Some days you are the dog, other days you are the fire hydrant... Another long sigh... Thanks for suffering me folks. -- 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> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
