MecSoft Corporation

When I try to use a containment region with a "Parallel Finishing" operation I get a bunch of extra up/down moves in the toolpath.

Below are two screen shots one with the containment region, the other without the containment region.

I don't understant what is going on, any help would be appreciated.

Thanks,
John

As the containment region selected is larger than the extents of part geometry, generating a parallel finishing operation retracts the tool to clearance plane as there is no surface to project down to near the side walls of the part. You could set the cut transfer to skim and specify a skim height. This would retract the tool the the specified height just above the highest point of the part geometry. Alternatively you could create catch plane (surface) below the part surface for the parallel finishing toolpath to project the toolpath down to this surface.

I read the reply from MecSoft support, but the toolpath generation still doesn't make sense to me.

Shouldn't the case with an oversize (in width) containment region act like the case where there is no containment region?

This seems to be the most sensible result. The retracts do nothing execpt to make the operation extremly inefficient.

I've found that I can get the desired result if I make my containment region slightly larger that the part silhoutte, but this is difficult on an odd shaped part.

See the attached example.

The way the algorithm works with containment and with no containment is different. In the case when containment geometry is selected, the cut pattern is pre-computed (including cut connections) and then projected down. If any portion of the containment does not project to any surfaces below it, a retract will be applied. (BTW, you can set Skim Clearance with a very small clearance value so that the retract does not go up to the clearance plane). In the case without containment, the cut pattern is assembled from a series of planes projected down to the bottom AFTER the projection toolpath is computed. In cases where the cut connection is on an edge of the surface (as in your first picture) the cut connection will be on the surface. In the previous case since the region is larger than the "projectable" area retracts ensue. Hope this makes sense.