Arcs in exact stop mode question


Does anyone know if machining arcs in exact stop mode (G9/G61) will
guarantee a precise arc or only precise end points? The manual only
metions end points so I am inclined to think it is only end points.
The rad in NC code is .8mm/.03".
Controller is Yasnac i80 and it does not have HPCC and is a production
HMC so I cannot use it for tests.
The alternative is to use High speed mode GON/GOFF (harder to change
the post).
DanP
Reply to
DanP
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The way I see it, it's positional accuracy only. The haas would go to all the rapid points coming from the same direction.
Reply to
vinny
End points only. If you have high speed mode...use it....tho I don't know how refined it is on a I-80. Most likely depends on the machine tool builder. It should be a pretty basic post edit to get it in there....what CAM system are you using?
Reply to
Zymrgy
Edgecam, high speed mode cannot be active on rapids, will do it with a flag.
DanP
Reply to
DanP
The only thing Exact Stop Check does on a Yasnac control is make sure that each move is fully done, stopped, before the next move starts. Normally, there's a small overlap between the decel at the end of one move and the accel for the next. The size of the accel/decel ramps, and of the overlap, is proportional to the cutting speed. The main functions of the normal overlap are to smooth and speed program execution, and to eliminate chatter or rubbing by keeping the tool moving at all times.
The overlap can cause problems, however, including sharp outside corners rounded off, slightly larger than cutter size rads if you just move straight to an interior corner and straight out, etc. It can aslo cause inaccuracies from slewing between moves if you're using lots of little segments to generate a shape. E.S.C. supresses those problems; but has no effect at all on the accuracy of interpolation between the endpoints.
KG
Reply to
Kirk Gordon
guarantee a precise arc
Only if you first break your arc into a large number of individual arc segments.
Reply to
PrecisionmachinisT
GON/GOF worked fine. A common mistake is to type GOFF/HOFF. I should have used cutter comp, the post slows down the feedrate on internal corners in cutter comp mode. Thank you all
DanP
Reply to
DanP

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