Machined features out of position

[ysheff]

When machining the last (3rd) operation on this part, all of the features (basically just a pocket with corners drilled out) are offset by exactly 0.01" in the Y+ direction

I have really tried to dig through to see what has caused this and am at a complete loss.  I am using the same origin as I used to make the soft jaw (which I had just made prior, so it hasn't moved).  My tool is correctly set to 0.125 diameter.  I have tried using wear comp which I typically use, and in computer.  Stock to leave is disabled.  What else could it be??

The part from the previous operations is within a +/- 0.001 or so, and regardless, I am measuring the offset from my reference surface which is against my soft jaw to the inside pocket, so even if the part was out of spec from previous operations, it should not change this measurement, only the wall on the other side of the pocket should change.

After a lot of frustration, I eventually got a successful result only by manually shifting the work offset on the machine 0.01".  If I need to machine my soft jaw again, I will need to change the offset back (or seperate into a new offset).   This just isn't right though, and I'd really like to know what is going on here!

There are a couple oddities, I know there's a gap with the moving soft jaw, hower it is just used for clamping, not positioning, and has no features machined so that shouldn't matter.  I'm also not machining the first half of this operation in the position that the original model is in, I did shift it in X with a pattern, due to how the soft jaws ended up, but this seems to be working just fine and the issue is only in Y, not X.

I am using a Haas VF2SS and the M130 post, with a minor tweak to add stock size.

[seth.madore · Accepted solution]

When you machined your jaws, did you have them clamped up, so as to be putting a load against them? It's "possible" that your CarveSmart aren't sitting proper against the vise base jaw, so when you clamp up the parts finally, it then deflects. Still though, .01" seems like an awful lot...

[ysheff]

Hello Seth,

Thank you for taking the time to respond to my question.  That's a great suggestion.  I do typically load up the jaws, but I also am normally using 2 jaws, not one.  I Forgot to do it this time as I was just machining the one jaw.  It doesn't seem like it should be moving that much, but definitely worth investigation.