RE: [mfg-smartcam] a little story about "i"'s and "J"'s

[Dave Coupar]

Chris,   Are your arcs being output as 360 degree circles with an R value? If so, this is the problem. R only works on arcs of < 360 degrees, as the Fanuc has no way of locating the center. If you want to cut full circles, and you want to use R for anything else, you'll have to modify your CG to check for a full circle as in this example.   @ARC < #MOV>< X#XPOS>< Y#YPOS>#IF(#TANG<360)< R#ARAD>#ELSE< I#XCTR J#YCTR>< F#FEED>   Dave -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Chris Peters Sent: Thursday, December 07, 2000 7:16 AM To: [EMAIL PROTECTED] Cc: Ernie Gemmel Subject: [mfg-smartcam] a little story about "i"'s and "J"'s Hi all, has anyone had trouble with interpolating bores with cutter comp?  The .pm4 geometry is completely round, but once you run it on the machine, you end up with an oval? our immediate action was to change the coded output from "R" values to "I" and "j" outputs, which seem to lock down the quadrant boundaries for Fanuc and gave us a nice round bore.   does this sound familiar to anyone?  you see the problem is there are other tapes on the floor that use "R" in cutter comp and they function perfectly well!   we tested different lead-ins and consistently, the i's and j's gave us a round hole, and the "r" gave us an oval.  it was a 5/16 em, cutting a .793 dia bore with circular lead-in and lead-out. the y dia is .010 larger than the x dia.   I'm pretty sure it's a Fanuc-ism that causes the ovality (a "best-fit" type scenario), but the question is, is it because we are crossing quad boundaries with an "R"? is it because our tool dia is less than half the interpolated dia? are there any mathematical braniacs who can decipher this geometric conundrum for us simple machine-heads?   go figure