Additive manufacturing in watchmaking is not a single technique: it's a family of processes that build material layer by layer instead of removing it from a block. The distinction between methods matters more than the generic name.
DMLS (Direct Metal Laser Sintering) is the most documented process in this field. A high-power fiber laser melts titanium powder — each layer is as thin as a human hair — following the digital profile of the piece. The platform descends, new material is deposited, the laser retraces the design. Thousands of cycles produce a continuous object, without welds and without joints between links. Panerai has used it since around 2016, first in tourbillons, then in cases like the PAM00768 and PAM01495: the internal cavities that only additive manufacturing allows reduce weight by 25% compared to subtractive titanium, and over 50% compared to steel with the same external geometry.
Selective Laser Melting (SLM) is conceptually similar but takes the metal to complete fusion rather than partial sintering: final density is higher. Holthinrichs uses Grade 5 titanium with this process — 48 hours to print 45 cases on a single build platform. The Oskar Pascal OP483 in ZR01 deposits 720 layers, then the rough part is turned and finished using conventional methods: printing doesn't eliminate final machining, it reduces it.
Metal Binder Jetting is a third way: instead of a laser, a print head deposits binder onto powder layers. It offers finer resolution and requires no support structures during printing, with greater design freedom. It's less widespread in watchmaking but present.
Oris and the Zurich Polytechnic developed a proprietary process for carbon fiber: fiber and polymer are interwoven in a controlled manner layer by layer, producing a coherent and repeatable weave, opposed to the random pattern of traditional pressed carbon cases. The technology comes from aerospace.
A note on the Galvanic Growth process used by Audemars Piguet for the logo on the Code 11.59 dial: sources classify it as 3D printing, but technically it's galvanic growth — controlled electrochemical deposition, not additive manufacturing through fusion or sintering. Terminological overlap is frequent; it's worth verifying the actual process case by case.
From the workbench: the granulated texture characteristic of DMLS is recognizable to the touch before surface finishing. Many pieces are sandblasted or micro-peened precisely to uniform that surface. Those familiar only with conventionally machined cases notice the difference immediately in hand — not in the declared weight, but in the distribution of mass.