What are your parameters on 3Shape Full Contour Crown.

[MrNeverFixit]

Hello,
i got a question guys, help me out. Could you please tell me what are your parameters on your 3shape design on full contour crown. Im just doing comparision on what we use and other labs are using. I would really appreciate. We have some fitting issues, so im trying to figure out if its our 3shape parameters. I am maintaining 3 roland mills, i keep on getting a complain if the mills are not milling right. Also i would like to try out the parameters/differences you guys are using, mill it and see the fittings.

Here is mine
Cement 0.050
Extra Cement 0.060
Dist to margin 1.00
Smooth dist 0.20
Drill Radius 0600
Drill comp. offset 11.50

Thanks
Hmar

 

[Brett Hansen CDT]

Here are the values I have been using for years and our fits are great.

Cement .020
Extra Cement .060
Dist to margin .1
Smooth dist .2
Drill radius .51
Drill Comp .53

The last two values are very important. They are determined by the the smallest tool that your milling strategy uses to mill out the cavity of the crown. For us, that tool is a 1.0 mm tool. That means I need those last two values to be a little more than half of the diameter of the 1.0 mm tool. Your drill comp offset is really large and that seems to be the one that may be causing your issues with fit. Good Luck! Let me know if it gets better.

 

[Brian442]

Don't sleep on dist to margin - this can make a big difference on fit. It should be approx the shortest length of the chamfer ± 0.2 or so. I usually like it around 0.3 or so depending on the prep. When I'm doing split file cases I always set it 0.1 less than the chamfer I set on the abutment

 

[npdynamite]

I will echo what Brett Hansen said. Most of your settings are pretty normal but that drill radius and drill comp are way out there. Those diameters do pertain to your burs, so I wouldn't necessarily just copy someone else's settings for that. I would give your mill support company a call and ask what settings they recommend for those two with the bur size your Rolands use. The only reason I don't suggest just using your actual bur diameter to derive this number is I do believe they add a little to the radius to prevent binding points that could potentially break the bur (that explanation may be a little off, but I think it's directionally right).

Hopefully that will fix everything. If you still aren't happy with the fits, it's time to start tweaking your other settings systematically. Other peoples specific settings here probably won't be terribly helpful for more than a ballpark estimate unless they are running the same milling strategies and your settings are already in the ballpark.

 

[CoolHandLuke]

I will echo what Brett Hansen said. Most of your settings are pretty normal but that drill radius and drill comp are way out there. Those diameters do pertain to your burs, so I wouldn't necessarily just copy someone else's settings for that. I would give your mill support company a call and ask what settings they recommend for those two with the bur size your Rolands use. The only reason I don't suggest just using your actual bur diameter to derive this number is I do believe they add a little to the radius to prevent binding points that could potentially break the bur (that explanation may be a little off, but I think it's directionally right).

Hopefully that will fix everything. If you still aren't happy with the fits, it's time to start tweaking your other settings systematically. Other peoples specific settings here probably won't be terribly helpful for more than a ballpark estimate unless they are running the same milling strategies and your settings are already in the ballpark.

right on, the extra diameter (or radius in this case) affords your mill 2 things: some tool runout/deflection space, and debris evacuation space.

in order to Mill a hole you must move in a spiral, down to the apex of the hole. with an end mill you must NOT move straight down like a drill would. this would make the tool flute clog with material bind up the tool, and break it. this is not 100% true for all materials, but for milling where large cuts are required, or where cutter fluid must get to the tip of the tool to cool it, this is true (i.e. titanium, cocr, polycarbonate and acetal)

with zirconia there is a LOT of loose debris though, so the extra radius for chip evac is 100% needed.