Why Machine Plastic Prototypes Instead of Injection Molding or 3D Printing?

Injection molding gives you production material and production geometry, but the mold investment is measured in weeks and thousands of dollars before you hold a single part. CNC machining skips the tooling entirely: one program, one fixture, parts off the machine the same day the material arrives.

3D printing is fast, but printed parts are anisotropic and their mechanical properties and surface finish depend on layer orientation. Machined parts are cut from solid stock — isotropic, dimensionally stable, and identical from the first piece to the last. For functional testing — snap fits, threaded inserts, drop tests, thermal cycling — a machined part behaves far closer to a molded part than a printed one does.

Machining also stays the right call for quantities you cannot print economically and should not mold yet. One-off prototypes, tolerance-critical fixtures, and bridge runs of a few hundred parts are all natural fits. When the design locks and the quantity grows into the 10–500 piece range, vacuum casting takes over cleanly — but the machined part is what validates the design in the first place.