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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