3d printing is an ideal choice for fit testing and general prototyping of almost anything. Even if you don't plan to produce your parts with 3d printing, you can still take advantage of the low cost and ease of concept realization.
3d printing is a suitable companion to other forms of manufacturing. 3d printing is excellent at making jigs, fixtures, and support tooling. With 3d printing, you can make everything from stencils, masks, and even custom CNC part jigs/fixtures.
We've done everything from custom vice jaws, to alignment jigs for lasers, CMM fixtures for accurate, repeatable use in metrology labs, and even full pallets for multiple part processing at the same time. All of which minimized machine downtime and increased productivity.
We can even print low use (Sub 10,000) injection mold inserts out of ceramic materials.
With some forms of 3d printing, particularly SLS, we can produce at full scale production. Ideal part quantities will vary depending on the part, but we have been able to produce 10s of thousands of parts at or below injection molding costs (when factoring in the cost of the mold).