Cr-Co Strategy

[DMC]

I had a sample Strategy for Cr-Co, but it is way too aggressive I think?

Feeds seem to me to be 2x too fast. Anyone have a general strategy they would like to share.

I'll try it. I am looking at 30-40 minutes per tooth (Coping) with my first few attempts and trying to get it closer to 25minutes.

Tools.....
4mm Torus (10,500 RPM 900mm/min X-Y feed, 250mm/minute Z-feed, 450mm/minute full-material removal, Climb-milling, 6 degree approach angle)
3mm Torus
2mm Ball (Pre-Finishing)
1.5mm Ball (Finishing Internal surface only)
1mm Ball (Internal Spiral and Touch-up other places)
.6mm Ball (Touch-up Internal)

Offset around the tooth is 3.2mm

Thanks.

 

[Drizzt]

I am currently milling around 25-28 min per unit . I use 3 tools , two 2mm and one 1 mm . I am not in town , when I return I will send you the details . Do you think the 0.6 mm tool is neccecary ? I mean does the extra time and tool will worth it ? What brand of CrCo discs are you gonna use?

 

[DMC]

SUM3d has very smart "Pencil-Milling" operation as an option that only mills a certian range of radius.

CAM looks for only small radius to mill. Nothing more.

Sometimes, it finds nothing to mill. Sometimes, it finds a few corners and lines.
I will post a screenshot of the tool path... The time to mill is only seconds.

What brand Cr-Co do you use? You first! LOL

You are roughing with only a 2mm ball? No Torid (Bull-nose)?

 

[DMC]

 

[Drizzt]

Mesa - Production of special alloys for the dental sector - Produzione di leghe speciali per il settore dentale - Herstellung von Sonderlegierungen fr den Zahnbereich - Production d’alliages spciaux pour le secteur dentaire

Show me yours !! LOL

Picasoft's standard strategy was very slow , maybe 45 min per unit . The strategy I am using now was made from Yenadent together with a Turkish technician , Vahit Topcu . For roughing it is used a 2 mm ball as you said . I am still a new at the whole CAM thing so I try to follow the footsteps of other more experienced users .

 

[DMC]

And, do you know if internakl spiral is clockwise, or anti-clockwise?

ANy RPM? or Feed values? Any other info?

Now, I am trying to go clockwise (down-milling) for 1mm internal finish Spiral.

I was going the other way (Climb-milling)


What about your tools?
The 1mm.....it is long and skinny (straight) or tapered to the ball?
Coatings? Black looking? Gold? Plain metal? Other?

Scott

 

[DMC]

I am being stupid this morning.

I am trying to use 1mm straight shank tool normally used for Zirconia on my Cr-Co metal. (only 3mm shank)

Needless to say, they are snapping left and right up high, right at the step from 3mm to 1mm.

I went to KaVo room and grabbed some BEEFY 1mm tools that are tapered to the ball.
They start at 6mm and taper to 1mm. Probably 10x stronger design, to resist tool deflection and vibrations.
MUCH Stronger! I dunno if this will make the difference that I am looking for or not?
I guess the correct tool is a good place to start? LOL (Dumb me)

I thought I had more tools laying around, but I guess not?

 

[Dentaleng]

For 1mm tool, have a 10-12 mm max. straight cutter and keep the oveall length to around 25 mm (Length from the collet). Tapered tools would avoid milling in straighter areas if Collission avoidance is programmed in CAM which would leave Some material.

 

[DMC]

I have 5axis mill and Premium CAM software to use tapered tools in continuous 5-axis motion.

I think this is correct way for metal. NOT straight shank tools in 3-axis.

Internal, straight walls of tooth are no problem to mill. CAM will adjust tool angle automatically. I do not have to think about it.

Just did a mill and looks OK. Fits Die. etc...

Pretty sure most all Metal strategies use 5-axis milling of 1mm for internal, and tool is tapered.

Been this way for a decade now. You sure you have done this before?? I have my doubts about you still. LOL

 

[Dentaleng]

Ohh, Ya I forgot that you had the best and premium of them all. Added to that you too Is the Best. If you know everything then why you want to know how others are milling CrCo

 

[DMC]

Thanks for your help.

Um'k?

 

[Drizzt]

Tomorrow when I am back , I will send you pictures of my tools . You still haven't told me about your discs !!

Rpm is about 18-20.000 I think , but again I will check to be sure .

Waiting for your CrCo discs brand

 

[Drizzt]

Do you think continious 5 axis or 3+2 is the best ?

 

[DMC]

Well, the KaVo and all other Metal milling I've seen is done with continious 5-axis for the 1mm internal using a tapered tool shank to resist deflection and vibrations.

Not a straight shank, like used for Zirconia and soft materials.

This is one of the few times I use the continious 5-axis. I just follow the Germans for guidance, but no luck today finding recommended RPMs and Feeds for Torid cutters....Only for Ball. I think my RPMs are too high for my 4mm and 3mm Torus (Bull-nose) cutters? I am beating up my 3mm too fast! 12,500 rpm....900 X-Y feed with only 400 Z feed and 400 feed when up against a wall (Full Material Removal scenerio)

I am looking at Datron PDF now....

I have not tested Porcelain on the Metal I am playing with. Could be sh1t material? I'll tell ya if I find something good. For now....I do not know.

 

[DMC]

For 1mm tool, have a 10-12 mm max. straight cutter and keep the oveall length to around 25 mm (Length from the collet). Tapered tools would avoid milling in straighter areas if Collission avoidance is programmed in CAM which would leave Some material.

You seriously do this with Cr-Co? I don't believe it.
Sounds like you are suggesting only 3-axis milling as well?

Show me...

I have "know-it-all" attitude when you point out the obvious. Of course I know a tapered tool will not cut down a verticle wall in 3-axis. That is so basic, that it is not worth pointing out. LOL Waste of band-width to state that info. Do you think I would own One Million Dollars ++ in CAD/CAM toys not knowing this? Dude?

Once again, until you get to know some of us here, and until you can prove you know something....it will be hard for you to talk to me. Sorry. That's just the way it is. I just don't listen to un-named sources from ?? background. That's just me.


What about tool coatings for Cr-Co and/or Titanium?
My tool supplier tells me the Cr-Co tooling is different, and cannot use same tools.

They are developing tooling, but not ready yet. I am trying a bag of random tools I have laying around and from ebay while I test things.

Not really doing any serious milling for real cases. That's going to be weeks down the road.

 

[Drizzt]

I don't have any issues with my porcelain . I am using a bonder and then opaque . No problems at all . And it is reasonably priced .

I am also considering trying these guys here .

S&S Scheftner - Labor Produkte - CAM-Materials

 

[Drizzt]

i will also try 5 axis continious for the internal for my next cases .

 

[Drizzt]

I use the same tools for CrCo and Ti . Don't know if it is the right thing to do , but I have no issues . I have milled some custom abutments and some primary telescopes with no problems at all .

 

[DMC]

I have measured 4um of T.I.R. on my tools just now. That seems great to me?

However, even after slowing my milling down quite a bit....I am STILL eating up tools left and right!

I think I have the wrong alloy??

It is from "Today's High-tech Alloys", in China. This is a box of mystery Metal I bought to experiment on. It is hard!! Going into the trash can now.....

Time to try Titanium that I know is correct! I bought from Supra Alloy....also have in the past.
Mills great! (99.9% pure for substructures....NOT for Abutments)

 

[DMC]

21 Minutes to Rough out a tooth.....

4mm Torid, then 3mm Torid....

Finishing now....but I think it will be another 20 minutes?

Now, I am almost certian it is the Metal that is too hard.

I think I am quitting on this brand, and for real throwing it away.

(My mill is shaking the whole building! Sounds like an Earth-mover or Bulldozer outside on tracks!

Neighbors are not going to be happy.)