Quote:
Originally Posted by billbo911
I was running 2D Pocket, not 2D Adaptive.
That said, I did look for "Stock to Leave" and sure enough, it was enabled and set to 0.02"!!! I think we found the culprit.
So now the question is, what is the best way to handle this?
Disable it?
Leave it enabled, but set to....?
How to finish it properly to size?
See above!
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I would recommend leaving it disabled. I will sometimes use it to compensate for bore size. For instance, if the model is 1.125 and we want a 1.124 hole without changing the model, we will put stock to leave as .0005 (leaving stock to leave for Z at 0). You can also leave negative stock to oversize something (ie -.0005 to get a 1.126 hole).
To get a good bearing size, I would recommend turning on a finish pass of about .005. This reduces cutter deflection and gives you a better finish and a more consistent size.
Also, you need to figure out what size your endmill actually is. Endmills are generally toleranced under (like +.000, -.002). Best way to figure this out is do a test cut, measure the part, and then take the difference as the difference in endmill size. It is hard to measure an internal bore well, so I would recommend calibrating your cutter on an external size (using micrometers would help). You can either change the endmill size in HSMExpress and re-post the code, or turn on cutter compensation for the critical features and then enter the size offset in the tool table on the machine. I do not know how tormach handles this, but it is pretty straight forward on a HAAS. Trick is making sure you get the cutter compensation in the right direction. We have just been entering the true endmill size in HSM for our router because we pretty much only use one tool and it is simpler that way.