Yeah, the hollow UV acrylic in the silicone mould is particularly cool - I'd often wondered how they went about doing this (I was previously wondering if it was done with a 3-D centrifuge, as is the case with certain types of hot plastic moulding), but no... time-controlled UV exposure; what a great idea.
The main question I have after watching those vids is why UE sometimes use laser scanning and sometimes use the hotwax-dipping method. Why the disparity? Obviously, they'll use the computer method if an audiologist sends them a 3-D laser-scan file digitally, via e-mail, instead of shipping a silicone impression, but that can't be the only circumstance under which UE are using that laser set-up because they have a scanner right there, in-house. Presumably, 3D printing of the laser scan is a more expensive process than the conventional, manual, wax-dipped silicone impression method, but still, that's no conclusive answer.
I'm also curious how they phase-align the various BA drivers in the shell - do they simply place the BA drivers in the shell the best way they'll fit, and then attempt to phase-align them electronically? I'm not sure that's possible, and yet there seems to be a wide disparity in BA driver placement, if one looks at photographs of various makes and models of custom IEMs.
Those are really good questions! Now i'm wondering too.