This work is a combination of meticulous planning and using cutting-edge technology - literally in both counts. First, we make a CAD design that will ensure precision machining. And by precision, I mean down to the last micron. The reason for this is that there are numerous factors that will determine a perfect outcome at that scale of things.
You see, Zircon is a shrinking raw material for use. Between the phases of machining and sintering the tooth, we have to ensure that there is an allowance for the shrinkage that must occur in the process.
So, what do we do? We first use an open process that we borrowed during our benchmarking exercise in the US - the use of sintering instead of hard-milling.
The raw zirconia is divided into pieces that are roughly the size of a tooth (ok, perhaps give a 150% scale). We then take the small pieces and fire them at temperatures above 1500 degrees (which is essentially the sintering process). This goes on for at least 10 hours, to ensure that the integrity of the material.
We then machine the copings to precise measurements in a 2-step procedure. First, we put it through rough cutting, using a 3mm ball end mill - which is then followed by similar finishing using a 1mm ball end mill.
Finally, we put it through further hardening using a turbine wheel and that is it!