ZZ Burs breaking with 3rd party PMMA

[CWilliams]

Hey all,

I know I'm probably trying to find a unicorn but I'm curious if anyone could shoot some pointers/ ideas over? I have an M4, and use zirkon's burs, but I use third party pmma (premiotemp multi) and my .5 and 2L bur tips have been snapping off more times than I appreciate... Of course, ZZ points the finger at Primotec and Primotec points the finger at ZZ *cue spider man meme,* neither actually try to help trouble shoot the issue bc that would require taking responsibility lolll

Notes-
I use the high quality strategy option with those familiar with zz nesting
No tight interproximals, no implants channels etc like were talking straight forward eggshells
No gnarly bite marks from the burs either when they snap, so I can't even tell when/ where it would occur
I've combed through the CNC paths and I cant possibly see any hang ups
I use anywhere from 3.5mm + cut out gap depending on disc thickness
Mill is routinely cleaned/ calibrated

 

[grantoz]

try wet milling

 

[redonGTR]

Sorry to be off topic
But where do you find the tool parameters for ZZ tools?
The webshop which the sales keep point me to does not have such info

 

[Treavor]

Try watching the milling process and see when it snaps. Maybe it's not during the milling but the tool change?

 

[Tyjhart9]

Hey all,

I know I'm probably trying to find a unicorn but I'm curious if anyone could shoot some pointers/ ideas over? I have an M4, and use zirkon's burs, but I use third party pmma (premiotemp multi) and my .5 and 2L bur tips have been snapping off more times than I appreciate... Of course, ZZ points the finger at Primotec and Primotec points the finger at ZZ *cue spider man meme,* neither actually try to help trouble shoot the issue bc that would require taking responsibility lolll

Notes-
I use the high quality strategy option with those familiar with zz nesting
No tight interproximals, no implants channels etc like were talking straight forward eggshells
No gnarly bite marks from the burs either when they snap, so I can't even tell when/ where it would occur
I've combed through the CNC paths and I cant possibly see any hang ups
I use anywhere from 3.5mm + cut out gap depending on disc thickness
Mill is routinely cleaned/ calibrated

View attachment 39118

I mill wet with an M1 using Chinese pmma and I've noticed that the 6T starts wearing out heavy around 70-75% of life. If I was pushing it too far, it would not mill all the way and left more material for the burs down the line to mill which would increase percentage of broken burs. If you're not milling wet, I would switch to that. So much more predictable. I'm milling 2-4 full arch all on X cases a week with great results. Also make sure that the plastic in the bur blocks are tightened sufficiently so that there is a clean transfer, if there is little pressure when placing the burs in the holder, its not tightened enough. After a while it finds a nice common point where it always locks into and you wont have to tight for months at a time.