Pocket is machined smaller than what it should be.

[Anonymous]

We are making a simple circular piece with 8 equal pockets with a draft angle using a 1" tool and a 0.015 z increment. The problem is that the curve used for the feature has a diameter of 1.99", and when we machined the first pocket, it had a diameter of 1.88". I checked the toolpaths and it was actually only opening to 1.88" instead of 1.99". A quick solution I did was creating a curve with a larger diameter to compensate the difference and it worked. Nevertheless, I want to know the reason this happened, since I can´t find an explanation. Thank you in advance.

[Anonymous · Accepted solution]

Hello @Anonymous 

The reason is that your feature is a roughing operation and the Finish allowance is set to .050'', that explain why you were about .100'' or so undersized in diameter on the first run. 

[Anonymous]

Thank you so much! You really helped me since I'm just starting out 🙂