surface question

[mike561h]

Hello friends,

 

I just surfaced a small radius button. 1/2 inch radius spherical .030 deep . The model shows the outside diameter is .342. I used scallop with collapse etc.. I have done mucho surfacing in my career. It came out of inspection the cmm said .455 radius. The .030 depth is correct and the .341 diam. at the end of the surface is good.

The toolpath is good. Crazy. We recut and still .450 rad. The tool follows the surfaces any answers would be appreciated.

 

thanks

[Cuda84]

Post file on the FTP site if you can.

[Mike Whitten CAD/CAM Contractors]

Maybe the part is good and the CMM is giving a bad number due to such a small arc segment. Can it be checked on a comparator?

 

Mike

[MLS]

+1 to what Michael said.

 

If that is it...may be possible to increase the number of points the CMM checks to calculate the arc so it gets a more accurate reading.

 

I would avoid small area radii on a CMM ...especially if they are kellered surfaces.

[htm01]

there is only .0016 between .5 and .455 rad at .250 wide,wouldn't take much for a false reading

[Die Sinker]

Ditto to what all are saying. It wouldn't take much to throw that radius off!

[mike561h]

thanks guys I let the inspectors know. We are shipping it has is. I can only do so much.