Not using cutter compensation in a Post?

[cncuser1]

Can anyone tell me what the effect would be if I tell my post-proccessor not to use cuttter compensation?

i.e. to not use G41/G42

[dcoupar]

You won't be able to compensate for undersize/oversize cutters by simply adding/subtracting from an offset register.

[cncuser1]

O.K. thanks, so only the nominal radius will be taken into account...

My final part dimension will have an error equal to the difference between nominal and actual cutter.

[dcoupar]

Right. So if you have an undersized cutter, then you'll have an oversized part, and you'll have to change the program. Why don't you want to use G41/G42?

[cncuser1]

Originally Posted by dcoupar Right. So if you have an undersized cutter, then you'll have an oversized part, and you'll have to change the program. Why don't you want to use G41/G42?

I have an old version of a post processesor that has a known bug. I do not have acess to a new version. It will invoke G41/G42 but omits G40 and a Z retract....Camworks and UPG (Universal Post Generaor).

I think I could generate the gcode without compensation and wind up with a usable part. Possibly generating the toolpath with the actual cutter size right from the start.

[psychomill]

Couldn't you or someone modify the post processor to outpu a "G40"? Most posts are user defined....

[cncuser1]

Originally Posted by psychomill Couldn't you or someone modify the post processor to outpu a "G40"? Most posts are user defined....

I think, but am not sure, that the source of the problem is in the CAM software (Camworks), not the post ( which is modiified by UPG).

I can see the proper G40 codes in the post ( in UPG), they just don't get inserted into the Gcodes when I generate them from within Camworks.