https://twitter.com/elonmusk/status/878821062326198272
Cast and cut titanium. They are about 4x5 feet and some of the largest (if not the largest) titanium castings in the world.
Titanium is an amazing material that is super hard to work with (special furnaces), and has its own sets of risks (titanium fire any one). I would love to see what goes into making those things because it simply has to be impressive.
1 - Most industrial DMLS/EBM systems have a build envelope far too small for this. A system like the Norsk Merke IV might have the required size, but parts built that that process still require post-machining. 2 - Tolerances. Casting -> Machining still offers greater control over the final geometry than additive processes, especially at that scale. 3 - Casting is a bit more design-agnostic than additive processes. 4 - QC processes for casting + machining are far more defined than for additive processes.
None of these are insurmountable challenges, so I'm sure in the future a laser-sintered/EBM/plasma-deposition process will be used or at least heavily-considered.
This is OK for the average power drill in your house. It isn't critical, and they can compensate for the porosity with extra materials.
If we were replacing a steel part with at TI one, then sintering might make sense, the extra strength, and lowered weight would compensate for the differences in materials.
They make extensive use of laser sintering in the SuperDraco engine (including the combustion chamber, which experiences tremendously high temperatures and pressures).
That being said, laser sintering is great for parts with weird geometries and structures that are hard to machine. A grid fin is really straightforward from a milling perspective, and would take advantage of the strengths of laser sintering.