If the mills hit that little plastic rim on the top of zirconias is it a problem?

[KingGhidorah]

Some zircs have little bits of a plastic rim running around the top part of the zirc, on the milling surface, is it an issue if the burs hit that a bit or should I move my units closer in to the puck to avoid hitting it. Roland 51-D

 

[JKraver]

Some zircs have little bits of a plastic rim running around the top part of the zirc, on the milling surface, is it an issue if the burs hit that a bit or should I move my units closer in to the puck to avoid hitting it. Roland 51-D

I would say it isn't ideal the biggest issue would be tool wrap if it melts the plastic and attaches to the tool because that will be a broken tool/ destroyed units for sure. If you nip it here and there I wouldn't worry about it.

 

[Car 54]

The issue I had with Beyond's plastic ring was chattering and tooth drop outs due to their glue not being totally continuous (air gaps) around the ring. So I use to nest those a bit away from the edge.

 

[sidesh0wb0b]

Some zircs have little bits of a plastic rim running around the top part of the zirc, on the milling surface, is it an issue if the burs hit that a bit or should I move my units closer in to the puck to avoid hitting it. Roland 51-D

its not ideal, but as long as its not causing issues with your tools or melting the plastic and doing damage....you should be ok.

i moved away from those pucks because i like nesting outside the puck on my 51D that way i get ~30units out of a puck instead of 22 or so

 

[A2WILLDO]

I would move it off the edge a little bit myself, especially using Diamond coated tools. A little love tap here and there isn't that big of a deal, but too often and deeper cuts is added stress on the collet / spindle and clogging for diamond coatings on tools. There are different strategies with different rpm's, feed rates and tooling for Zirconia, Pmma, Wax, Resin, etc., for more reasons other than just to cut a good part.

 

[Car 54]

I would move it off the edge a little bit myself, especially using Diamond coated tools. A little love tap here and there isn't that big of a deal, but too often and deeper cuts is added stress on the collet / spindle and clogging for diamond coatings on tools. There are different strategies with different rpm's, feed rates and tooling for Zirconia, Pmma, Wax, Resin, etc., for more reasons other than just to cut a good part.

Good point about diamonds, as I've only used carbides and coated carbides.