Titanium and stainless steel cover most of the metal orthopedic prototypes Lab Ready machines, and the two get compared often enough that it's worth laying out plainly what actually separates them for a prototype program — because the right answer changes depending on what the part needs to do, not just what the final device will ship in.

Titanium: biocompatibility and strength-to-weight

Grade 2 and Grade 5 (Ti-6Al-4V) titanium are the default choice for implantable or near-implant components — trial implants, fixation hardware, and anything where biocompatibility and strength-to-weight ratio matter more than raw hardness. Titanium also machines and 3D prints well; see DMLS vs SLM for how it behaves specifically in metal additive manufacturing.

Stainless steel: hardness, cost and a wider grade range

Stainless steel — 303, 304/304L, 316/316L, 420 and 17-4 PH are the grades run most often — is the more common choice for surgical instruments, jigs and fixtures, and any component where hardness, wear resistance or cost matter more than implant-grade biocompatibility. 17-4 PH and 420 in particular heat-treat to a hardness range machining alone can't reach, which matters for cutting or bearing features on an instrument. See the surgical instrument material notes for specifics.

Cobalt-chrome as a third option

For parts that need titanium-level biocompatibility with higher wear resistance than titanium alone provides — an articulating surface on a joint reconstruction prototype, for example — cobalt-chrome is the usual third option, available in both CNC-machined and metal 3D printed form.

Deciding by application, not by habit

The fastest way to land on the right material is to start with what the part needs to do — implant contact, wear surface, cutting edge, fixture — rather than defaulting to whichever alloy was used on the last project. The full grade list and available finishes are on the Materials & Finishing page; if the application is still being worked out, describe the part and its use and material selection is part of the quote review.