3Shape D2000 with AG Motion 2 PMMA Problem

[S.A.Collins]

Maybe someone can help me with this....

I've had this set up for almost 2 years now and have been very happy with it, I mill titanium abutments, wax, emax, and zirconia with perfect fits, but not PMMA. Every time I have milled PMMA it is too tight and just doesnt fit right. I've talked to 3shape support, and I have talked to ag support but nobody can give me an answer. The best Iv'e got from them is to possibly increase the cement gap amount when designing it. I've increased it a little, then a lot, then doubled and still too tight, then I increase more and it is nowhere even close anymore. Iv'e tried several brands of PMMA including AG's but it all comes out the same. Has anyone had the same problem or have the same set up with positive results? The last 2 Chicago shows this was on my list of things to get to the bottom of and I still haven't solved it.

 

[cadfan]

whats the problem tight what kind of burs wet or dry what kind of work which gap parameters ?

 

[eyeloveteeth]

are you saying ALL PMMA mills tight? and everything @cadfan is asking

 

[JMN]

Aside from gap spacing, the possibility exists that the burr is overheating from too high rotational speed and the material is not being cut as expected.
Are the burrs staying very clean?
Are the milling marks clear, or smeary?

 

[PRO ARTS DL]

I've always had a similar/same problem with the Motion 2. The only way I get good/OK fit is if I use AG PMMA and new burs. The fit gets ok as the burs get worn down.

I've tried other brands PMMA and I get really bad fit. You can even notice the noise difference when milling AG PMMA vs other brands. Other brands make a lot more noise. Too bad we can't modify the strategies to fix this. I think AG PMMA is a lot softer? or easier to mill. The strategies are just not made for other brands. Who knows

 

[eyeloveteeth]

we mill PMMA on a daily basis on a bevy of machines with ZERO problems? we've been using Yamahachi PMMA and Sagemax PMMA

milled on DWX 50, 51D, ZZ M5, ZZ M1, DMG Dental 10,

 

[S.A.Collins]

whats the problem tight what kind of burs wet or dry what kind of work which gap parameters ?

I'm milling wet, Using the normal AG burs. I started with .030 cement gap and .070 axtra cement gap, increasing by .010 til I doubled and beyond with no luck, they always are just a little bit too small, its almost like the margins would fit ok if you reamed the hell out of the inside of the crown, cause by the time it goes down from increasing cement gap the margins are way open. I have used it for temporary crowns and bridges.

 

[S.A.Collins]

Aside from gap spacing, the possibility exists that the burr is overheating from too high rotational speed and the material is not being cut as expected.
Are the burrs staying very clean?
Are the milling marks clear, or smeary?

the end result looks beautiful and smooth. Doesn't look like there is any problem with burs gumming up or smearing

 

[S.A.Collins]

I've always had a similar/same problem with the Motion 2. The only way I get good/OK fit is if I use AG PMMA and new burs. The fit gets ok as the burs get worn down.

I've tried other brands PMMA and I get really bad fit. You can even notice the noise difference when milling AG PMMA vs other brands. Other brands make a lot more noise. Too bad we can't modify the strategies to fix this. I think AG PMMA is a lot softer? or easier to mill. The strategies are just not made for other brands. Who knows

I read somewhere else that someone said this but I am still having the problem with AG brand PMMA?? Thanks everyone for chiming in.

 

[JMN]

the end result looks beautiful and smooth. Doesn't look like there is any problem with burs gumming up or smearing

Well, sorry, that's as helpful as I can get on this one.
Actually, just had a silly thought. You are certain the computers are using the milling strategy set you are modifying, if you see no change after changing things, that's just weird.

 

[S.A.Collins]

Well, sorry, that's as helpful as I can get on this one.
Actually, just had a silly thought. You are certain the computers are using the milling strategy set you are modifying, if you see no change after changing things, that's just weird.

I do see a change once I start drastically increasing the cement gap but by that time its like a boot on a rooster foot. Every other material has a strategy that uses 3 burs, but pmma is only the 2 larger tools, I wonder if that has something to do with it.

 

[JMN]

I do see a change once I start drastically increasing the cement gap but by that time its like a boot on a rooster foot. Every other material has a strategy that uses 3 burs, but pmma is only the 2 larger tools, I wonder if that has something to do with it.

Well, you've got my sympathy and interest. I'll be watching.

 

[Sevan P]

BURS BURS BURS. I had serious isues with a dwx50 and pmma tight, then loose never consistent.Now on my VHF and Mini spot on all the time. 0.03 margin cement gap and 0.09 extra cement gap. Sierra Razor sharp tools on the VHF S1 and the Wieland Basic 2.5mm 1mm and .7mm basic tools drop right in. No Diamonds.

 

[cadfan]

I'm milling wet, Using the normal AG burs. I started with .030 cement gap and .070 axtra cement gap, increasing by .010 til I doubled and beyond with no luck, they always are just a little bit too small, its almost like the margins would fit ok if you reamed the hell out of the inside of the crown, cause by the time it goes down from increasing cement gap the margins are way open. I have used it for temporary crowns and bridges.

Cement gap is for general fit try 0.090 extra cement gap is as far as i know 3 shape same as exo for production and scan problems , you have 5 mp cameras and good strat it should work with 0.015 ( this opens the margins because of scan and production issues ) and as result faster fit . Try this first tell what happened burrs are less the problem as long they are not older than 8 hours because your wet . Margin is milled with 0.6 ? or 1 mm

 

[DanM]

Maybe someone can help me with this....

I've had this set up for almost 2 years now and have been very happy with it, I mill titanium abutments, wax, emax, and zirconia with perfect fits, but not PMMA. Every time I have milled PMMA it is too tight and just doesnt fit right. I've talked to 3shape support, and I have talked to ag support but nobody can give me an answer. The best Iv'e got from them is to possibly increase the cement gap amount when designing it. I've increased it a little, then a lot, then doubled and still too tight, then I increase more and it is nowhere even close anymore. Iv'e tried several brands of PMMA including AG's but it all comes out the same. Has anyone had the same problem or have the same set up with positive results? The last 2 Chicago shows this was on my list of things to get to the bottom of and I still haven't solved it.

Had the same problem with my Mini, had to go 3x to 4x spacer settings, I think 0.12/0.16. I got a Select and same problem, worked on the milling strategies and got decent results. I changed to a different manufacture bur (Sierra Razor as well) on the Select and works great with standard spacer settings and milling strategies. I didn't try changing burs on the Mini because of the touch plate.

 

[Sevan P]

Had the same problem with my Mini, had to go 3x to 4x spacer settings, I think 0.12/0.16. I got a Select and same problem, worked on the milling strategies and got decent results. I changed to a different manufacture bur (Sierra Razor as well) on the Select and works great with standard spacer settings and milling strategies. I didn't try changing burs on the Mini because of the touch plate.

You can run the razor sharps on the mini no issue. But the wieland basic burs work just as well. On my vhf k4 that is all I ever ran for wax pmma is the razor sharp burs. Even for zirconia I will run the 1mm razor sharp for 300 to 400 units.

Sent from my SM-G920V using Tapatalk

 

[JohnWilson]

Cement spacer is a a band aid for poor machining.

 

[funkyfester]

Never been able to mill pmma on the motion 2 with ag splintec snaps the the T2 bur, with ag own burs! given up wasting time and snapping brand new burs why they try to solve the problem seem a shame when get perfect mills with degos blanks and bredent burs!

 

[JMIO]

Hello! im new to this site. And really noob in the CADCAM world!

Been working with the Motion 2 for 1 year now, and we had a lot of trouble milling PMMA. At first everything went well, actually really well. But now it keeps breaking the burs (AG burs) with every work...... Im done with PMMA. Lot of money wasted on burs and blanks....

(sorry for my english and HI from Chile!)

 

[Affinity]

If youre milling pmma with diamond coated tools, thats probably why youre having breakage.