zdental
Member
Full Member
- Messages
- 29
- Reaction score
- 4
Pink fits her also nice
Hi Dimitris, do you know if they sell these units to the UK? shame i didn't get chance to pick your brains while in cologne!
Adam
Dimitris, i gather you are really pleased with it?Hey Adam ,
I don't know but I can find out for you tomorrow . It was a shame mate but we will catch up soon , I am sure !
Dimitris, i gather you are really pleased with it?
Hi Dimitris, do you know if they sell these units to the UK? shame i didn't get chance to pick your brains while in cologne!
Adam
Hey everyone !! Sorry I was in the IDS so too busy !!
adam4321 , I don't have a problem with the soft CoCr , but since I have the equipment to mill hard CoCr , it is so faster and doesn't make any sense for my lab's needs to buy a 10k euros furnace to do that .
I can see pro's and cons for both materials. I'm thinking that the Soft CrCo will mill quicker and use fewer burs over the course of a year and whilst the Hard CrCo will take longer to mill it wont need a further firing to sinter. There are a couple of sintering furnaces that are able to sinter Zr and the Soft CrCo (not at the same time!) but I so far I haven't managed to find anyone that actually uses one to get some user feedback.
Dimitris, do you see much advantage in the 2.5kw water cooled spindle in your D40 over the 1.3kw air cooled one in the D15?
Actually a machine with a 1.3Kw spindle and 100w servos is really an underpowered configuration for machining a tough material such as CoCr, its not all that difficult to stall the spindle or trip the drives.
It can be done however you are really taxing the spindle and will be forced to slow everything down and make scarifies such as: longer cycle times, lowered tool and spindle life as well as less than optimum surface finish.
I'm not sure of the tool shank diameter for this machine, however form images it appears to be only 4mm and if so, is another limiting factor.
Looking at the image posted I would say the machining result is OK. I would like to know how long it took and what the tool-life is for non-precious metal CoCr alloy. I would also love to listen to it cut- you can tell much by listing.
I say Ok based on the "chatter" that appears on the resulting rough surface finish that also exhibits signs of gouging. I also noticed what appears to be use of a "parallel plane" or a "kellering" type of finish machining strategy. They types of inefficient (typically the most inefficient available) finish "anomalies" and machining strategy choices are typically representative of limited CAM functionality and/or machine construction and/or component selection. (i.e. low power spindle/drives, fixturing, etc.) that force the use of less than optimum machining strategies that require less from the machine.
It may also be a choice made by the customer to have this rougher finish for aid in cementation, however there are more efficient ways to accomplish this as well.
I only mention the above as a kind of "be aware" as a more substantial machine would be recommended to meet any significant production requirements.
Obviously Yenadent has "more substantial" offerings available but I can give you and idea of what I am referring to by comparing the results posted with that which we are able to achieve with our Versamill.
Images are the direct results from the machining process- no hand-work.
Additionally, in my opinion the milling of "soft" metals are still not a complete replacement for full metal . Perfecting this material/process has been going on for many years and though it has proven to be effective for smaller restoration, larger frameworks are still a problem due to the unavoidable conditions associated with the process (i.e. detachment of bridge units and deformation of the bridge framework and others).
Just another fellow's opinion...
Hey Drizzt,
Yes, I figured you did your CoCr work on the more "substantial" machine- 20-25 minutes for a multi-unit is a pretty good time.
We get about 30% of our customers wanting the fine finish I have shown on the occlusal (still within the time-range you have specified) however most seem to want it on the prep side (if I told you the cycle time, you wouldn't believe me anyway)
We just provide our customers the opportunity to choose the finish they prefer- there is of course, always a trade-off in cycle time. You might be surprised by the number of people that, at first do not expect this, it prompted me to prepare a short piece about it: CNC Dental Milling: Cycle Time and Surface Finish
Best
Steve