Problem machine simulation with collet PocketNC V2-10

Hi there,
I´ve got a problem with mastercam´21 in combination with my PocketNC V2-10. I´m trying the first time to mill a round object (simple 24 straight toothed gear: Y-axis up and down plus B-axis turning and -Z-milling in and out).
My plan is to fixing the round material with the collet and using the mastercam 5- axis milling function called “Swarf milling”. The problem is that mastercam/pocketnc simulation doesn´t center the material in the middle of Y/B axis, so that every time (I´ve tryed several things out) the object plane (wcs, created plane etc.) center point is out of the center point of the machines collet. The effect is that the G- code program generate a progressive translation of the X-axis which I´don´t want. The X-axis should be stay in place.
So how can I replace the “vise” type material fixture against an collet (with X=0/Y=0/Z=0)type one?

Many thanks for help in advance.

Hi Dan76,

My knowledge of Mastercam is limited but I do have some resources I can draw on to hopefully help you solve this issue.

Could you please upload your Mastercam file? That will help a lot in diagnosing the issue.


Hi Q,

I´ve already fixed the issiue in the mastercam nci program.
So the real milling proces on the PocketNC machine runs well and the parts are done. But I still have the displacement problem in the simulation. See picture.
I think there is the collet data is missing in the mastercam/PocketNCpost processor bunch wich are provided for download.



Hi Dan76,

I reached out to Mastercam’s applications team and this is the response I received:

Please check out the attached video here. I think this is where they are running into issues.

Machine simulation positions are done automatically by snapping the operations plane to the machine zero point (and sometimes in a less than predictable manner). A manual shift can be used by switching from the default automatic. I think since most PocketNC parts are programmed from machine centerline typically you would manually define the plane position for Machine Sim @ X0Y0Z0.

If that does not solve the issue it may be more effective to reach out to Mastercam directly since they are the ones that built the post and sim for the Pocket NC.


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