[duckslayer]

I have a 94 vf2. I have a fixture that when i pick up x,y as zero it repeats. in the same fixture the part is off .015 to .02 in x. I checked the program and for anything loose from the table up. After the part is cut I return to zero pick up the fixture again and it is at zero.I am doing parts half from one side flip and repeat. There is always a mismatch. I checked for backlash and can't find any. Lost looking for a direction to go.

[Matt@RFR]

I would set an unused offset in X on a face of the blank material of the part itself before machining, then relocate that same edge and I bet you'll find your discrepancy. I see no way that a work offset shift could occur during machining, then return to zero after machining except:

Did a G52 sneek into your program?

Another thing you could try is to mount an indicator on the table or vice, set against the fixture itself in the X direction, and watch the indicator during machining.

[Machineit]

Would love to see the program. Is this a setup and a program that you have used before? Could you post a picture of the fixture.

With that much error, I don't think that it is wear in the machine. Sounds like a program, clamping or fixture error.

Cheers,

Mike

[helix77]

make sure you are not useing g52... assuming that you dont have a tool that is pushing the part around due to being dull or over run... i would bet that its in the program

[duckslayer]

Ok. Now I am feeling kind of stupid. I think it was a clamping error. I am using a 1.250 thick tooling plate with 3/8-16 stainless thread inserts and kurt mite bites. I was only torquing to 150 in pounds. went to 200 and seems to have helped. I only cut mold and die stuff at work so the fixture thing is still kind of trial and error. How much toque can I put on these things without stripping them? (wedge)

[Matt@RFR]

A couple things: Kurt has nothing to do with Mitee-Bite (as far as I know, anyway). Go to MB's website, find the product you are using and you will see that they list torque values for you.

Mitee-Bite Products Co.

Depending on the MB product you are using, backup bars will need to be much heavier, and secured with more/bigger bolts than you are probably thinking. A picture of your setup (like requested once allready) would help us help you.