FeatureCAM breaking my inserts !!!!

I'm using Featurecam 2007 (V13.1.0.28) to produce code for a new to me Beaver TC20 lathe which is even older than the software ! (1989). It has a Sinumerik 820T controller, and I'm using a slightly tweaked post processor for the Sinumerik 810T as they are code compatible.

Testing using a simple single arc to form a domed end on a bar, all goes well roughing, but on the finishing pass the tool is traversed 6.6 mm beyond the centreline, then engaged, resulting in an upward force on the insert until it has cross the centreline back into safe territory. This of course chips the insert.

The Featurecam simulation clearly shows the issue :

Attachment 400742

Here is the code segment:
Attachment 400744

And the chipped insert:

Attachment 400746

Video here

https://www.youtube.com/watch?v=47wbULKpPtg

I don't seem to be able to find any settings to prevent this so any suggestions would be appreciated

double post

According to the simulation, the lead-in move starts under the centerline, then touches the stock after crossing the centerline. I admit I don't know much about turning, but isn't this how it's supposed to be?

In the video, the cutter seems to be too close to the stock and touches it at the beginning of the lead-in move.

The same tool is being used for roughing and finishing, so Featurecam should surely know precisely where the tool is for the finish pass.?

I've solved the problem by altering the finish pass 'Engage Angle' under the MISC tab from the zero that it was, to 30 degrees. Tips now survive the experience :)


Attachment 400788


https://www.youtube.com/watch?v=9t50juKYv2Y