MILLING SAME CROWN BUT DIFFERENT RESULTS?

[Sam_ids]

Hi, Ive been having this issue for months. any tips or suggestions would be greatly appreciated!
I am experiencing size differences (height and width) in the Zirconia crowns ive been milling.
almost half of the zirconia crowns from my Ceramill Motion 2 (nested with Ceramill Match 2) have been coming out shorter, and gapped with no mesial/distal contact.
I am also using VHF to CAM and nest on another mill.. (these come out perfect in size and fitment everytime)
I use the same zirconia discs on both and imput the discs by Scale Factor.
I recently calibrated my ceramill motion 2 (5-axis)
another thing to note is my ceramill uses 2.5, 1.0 and 0.6 burs (currently using CeraDirect DC)
the other machine uses 2.0, 1.0 and 0.6 burs (VHF K4-DLC)
maybe settings in the ceramill motion 2?

 

[richgreen]

Had a client with a similar challenge recently. Turns out the answer was a thorough cleaning of spindle and replacing the collet.

 

[tuyere]

Shorter by how much? Is the defect present across all of the part, or only in specific parts? Is the issue showing up in places that are face milled, side milled, or both?
Could be a bunch of things- damaged tooling, tooling that's incorrectly configured in CAM (i.e. it thinks the tooling is longer than it is, different diameter, a different shape, etc),bad collet, bad spindle, machine parts in need of cleaning, lack of calibration, an issue with the toolpaths being generated, etc. The characteristics of how the issue manifests can help narrow it down.

 

[A. M.]

I think the issue is the Scale Factor.
You are probably entering the wrong number.
If you need a new collet you would have different issues, also if need a new spindle, the mill would stop