3Shape D2000 with AG Motion 2 PMMA Problem

[brayks]

...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

Your problem is most likely related to your "milling condition" and vibration/chatter. Your tool/bur is likely deflecting and not actually machining the stock it was intending to remove leaving too much stock for the following tool. Result is bad fits, poor finishes and broken or heavily worn tools.

The "milling condition" is a function of many parameters including: SFM (function of spindle speed & tool diameter),chip load, feed rate and machine and fixture rigidity.

Actually tool/bur manufacturers provide a chart that, for various materials being machined, shows the recommended SFM range, feed rate and spindle speed. Some even show the chip load which basically is the thickness of a chip removed by one cutting edge of the tool. Chip load is a function of cutting feed rate, spindle speed and number of tool cutting teeth (flutes).

Noise is a function of vibration induced chatter, which means the tool (bur) is bouncing around slamming in and out of the cut which will cause: bad fits (areas are not being completely machined),poor finishes, excessive tool wear and tool breakage.

The above is a simple overview of a more complex matter beyond what I can provide in this post but I believe it pretty much gets to the point.

It's unbelievable/unacceptable to me that a user cannot change a templates machining parameters associated with optimizing the machining condition (depth of cut, step-over values, spindle rpm, feed rates, etc). but you should at least be able to manually adjust the feed rate and spindle speed via feed rate override "buttons"

I would first use carbide or better yet carbide coated tools (we use TiSiN). Slow the feed rate down via the feed rate override button. You should hear a difference as the reduction in feed rate reduces the vibration. Also check your spindle speed as this will also have an effect. Depending on your tool diameter and coating a range of say 25,000 to 38,000 rpm should work well - that is a wide range and the optimum value can often be found withing a 100 rpm band.

Just a thought...

 

[[email protected]]

You need shorter tools, you're experiencing tool deflection - that's why it's okay at start.
Pmma is tough to mill - so better wet and probably time to try a better suited mill too.
You need better strategy.

 

[Jesse Zamarripa]

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!)

Call our tech support at 818-654-7069. We have a lot of experience with PMMA on the Motion 2. Users for 5 years, thanks

 

[Jesse Zamarripa]

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.

We mill PMMA on the motion 2 all the time. Feel free to contact us at 818-654-7069 to discuss. Thanks!

 

[grant somers]

we have the same problem with Roland DX 50 and 3 shapes........cant figure it out...tried increasing everything! natta!

 

[Sevan P]

we have the same problem with Roland DX 50 and 3 shapes........cant figure it out...tried increasing everything! natta!

Get a set of Sierra razor sharp burs, set the drill comp and radius to .550 and die spacer the .03 margin and .10 extra and give it a shot. I have zero issues milling puma in my vhf and wieland mills. It is all about the right bur.

Sent from my SM-G920V using Tapatalk

 

[grant somers]

Get a set of Sierra razor sharp burs, set the drill comp and radius to .550 and die spacer the .03 margin and .10 extra and give it a shot. I have zero issues milling puma in my vhf and wieland mills. It is all about the right bur.

Sent from my SM-G920V using Tapatalk

WOW.....thanks mate!!!!.....milled my first one after changing burs and using your specs......PERFECT FIT!!!!

 

[Sevan P]

WOW.....thanks mate!!!!.....milled my first one after changing burs and using your specs......PERFECT FIT!!!!

Excellent! If you ever need to tighten it up a bit for over implants the biggest thing will be drill comp, drop it a bit and run cam simulation and check if everything cleared and. It unmilled areas inside the cavity. Or try dropping the die spaver a. It but thatvwont make a big difference.

Sent from my SM-G920V using Tapatalk