Both cases are made from the same basic materials. The composition is 80% Zirconia powder and 20% Paraffin binder. This mixture would be a greenish color so a color pigment is added to make the black color. The 317 is made in a 7 step process. Because of the complex shape of the middle case, the PAM317 undergoes
an injection molding process. It would not be possible to make this case the same way as the 292 because of the middle case.
The first step is the preparation of the powder.
The second step is the injection of the mixture into the mold itself. At this point the case blank is actually 58mm!
The 3rd step is the machining of the middle case and other components.
After this the binding material is removed.
The 5th step involves the sintering of the ceramic. This is where the original case size shrinks down to the 44mm case size,
and where the completion of the ceramic hardness is completed. The sintering is essentially heating up the different components. All of the
components shrink dramatically during this process.
After this the final grinding process occurs in the hard stage of the ceramic case.
The last step is the finishing.
The 292 is made differently, It starts with a ceramic blank. I believe it uses more of a grinding and milling process similar to how a steel or gold watch is produced.
Here is some information on Ceramic Sintering from Wikipedia:
Sintering is part of the firing process used in the manufacture of pottery and other ceramic objects. Some ceramic raw materials have a lower affinity for water and a lower plasticity index than clay, requiring organic additives in the stages before sintering. The general procedure of creating ceramic objects via sintering of powders includes:
Mixing water, binder, deflocculant, and unfired ceramic powder to form a slurry
Spray-drying the slurry
Putting the spray dried powder into a mold and pressing it to form a green body (an unsintered ceramic item)
Heating the green body at low temperature to burn off the binder
Sintering at a high temperature to fuse the ceramic particles together
All the characteristic temperatures associated to phases transformation, glass transitions and melting points, occurring during a sinterisation cycle of a particular ceramics formulation (i.e. tails and frits) can be easily obtained by observing the expansion-temperature curves during optical dilatometer thermal analysis. In fact, sinterisation is associated to a remarkable shrinkage of the material because glass phases flow, once their transition temperature is reached, and start consolidating the powdery structure and considerably reducing the porosity of the material.
There are two types of sintering: with pressure (also known as hot pressing), and without pressure. Pressureless sintering is possible with graded metal-ceramic composites, with a nanoparticle sintering aid and bulk molding technology. A variant used for 3D shapes is called hot isostatic pressing.
***** I would like to thank Chad from the BH boutique for his tremendous assistance filling in the missing pieces of information. Chad always goes the extra mile