Roughing Path Problem

[reo]

The couple of 3d cuts I have done using a roughing path seem to have a problem with the roughing path cutting into the finish path area in places. I used the v3m lily file with the concave dish style that is a free sample from Vectric. I have checked all the settings a few times in the partworks 3d software. When I do a preview the files looks fine on the screem. When I actually cut the files the roughing path has a few spots where it cuts into the finishing area. I import the 3d model into Partworks and preview there with no cutting error on the screen. I have read some other posts that are concerned with the collet hitting the surface but that is not the problem here.

[tmerrill]

Kevin,

If the preview looks good, then the toolpaths should be good. I assume you are using different tools for the roughing and finishing paths. If so, make sure you are zeroing them at the same spot. Most likely, either your roughing path is zeroed too deep or your finish path too shallow. Hope this makes sense.
Tim

[reo]

Thanks, I have zeroing at the same spot. The tools are different .25 end mill for roughing and .125 tapered ballnose for finishing. I have been zeroing at about the center of the piece.

[tmerrill]

Just be sure the center of the piece isn't being cut by the roughing pass.

[reo]

It is but the aluminum zero plate stradles this area. Could it be flexing?

[myxpykalix]

I try to alway leave material on at least one side the original height upon which to re-Z.
I always Zero my X,Y in the center and usually for 3d toolpaths that gets cut away.

How bout posting a picture that usually always tells more than you can explain.
Let me ask a stupid question...you are cutting the roughing pass first right?

[reo]

The problem seems to have been me using the Shopbot(arcs)(Inch) post processor as opposed to the Shopbot(inch) post processor. When I use the (inch) processor all is well. I had thought I read in a forum post to always use the (arcs)(inch) but the use of the arcs with my PRS Standard causes the roughing path to cut into finish areas.
Thanks for all the help