How can I modify (as a op.) the path of a tool?
'Cause the resulting holes are not at the wanted dimensions (they are smaller in fact).
Increasing or decreasing the tool diameter?(with G42 code)
And one more thing...The final holes diameters have no constant value. The machine setup is wrong?
if you don't what to use G41 or 42 when your cam system asks for the cutter dia. instead of putting in .25 you could put in .255 or .245 for the value(larger # smaller the hole) I do this a lot if I'm using the same tool for ruffling and finish work it called lying to the software but it works if your hole are not the same you could have other issue most likely in set up or tool I would not blame the machine a this time try a slower feed rate
if you think that you have an encoder issue bolt a block to the table put a dial indicator in the spindle put a load on the side of the block with the indicator set a zero on the incator and set x on controller go into mdi program G01 x-.1 F.5 see if indicator moved .1 then in mdi G01 x0 f.5 see if indicator is reading zero do the same with Y axis
What you are describing sound more like a mechanical looseness in your drive system or the Loopgain and Balance are out of adjustment. Normally, egg shaped holes are a direct result of a mechanical error.