This video clip is about 1-2mm into the build, so this is the very close to the bottom edge of the part (which, to be clear, is lying on its side). A lot of what's being printed during this clip is support structures & ribs that will help hold the part to the build plate, but you can clearly see the general shape of the part already.
This is 6th iteration on this build. In other words, we printed 5 parts before this one, and each of them failed for one reason or another. We've (and by we I mean mostly Dave Bartosik, the head Additive Technologist at DRT, with me trying to look over his shoulder) made a bunch of modifications to the build to help the part come out within spec, and I'm hoping that today we end up with something that has consistent inner diameters and is more or less useable.
Anyway, what you're seeing here is a 400 watt ytterbium fiber laser in the process of melting 30 micron layers of titanium powder. The recoating arm spreads a thin layer of powder, and then the laser scans a cross sectional slice of the part, and then the process repeats.
When the video goes into slow motion, notice the smoke that's coming off of the weld pool. The machine has a laminar flow of argon gas that's blown across the build platform (from top to bottom in this video) that pulls the soot away and filters it outside the machine.