3D Printing for “Hybrid” Tooling

An aerospace contractor added a 3D printer to help make custom tooling. In many cases, this means combining printed and machined components.

I recently had the opportunity to visit CPI Aerostructures, a company that is much different from those we typically cover in Modern Machine Shop. CPI is not a machine shop, and it doesn’t machine discrete parts. Instead, it sources those parts from a network of suppliers and fashions them into subassemblies for aircraft at its facility in Long Island, New York.

But although its business looks different, CPI has the same need for custom tooling—fixtures, check gages, jigs, etc.—that machine shops do. Like many machining facilities, it has an in-house toolroom with manual machining and welding equipment to help produce that tooling.

Since 2013, CPI has also relied on a fused deposition modeling (FDM) 3D printer for tooling applications (which is the reason I visited, on behalf of Additive Manufacturing). Using this printer, the engineering department is able to print tools or parts of tools much more quickly and cheaply than having them machined. Increasingly, CPI finds itself using this capacity to produce “hybrid” tooling that combines both machined and 3D-printed parts, such as the fixture pictured above.

This hybrid fixture is used to hold an engine inlet during drilling, and features a machined aluminum ring with 3D-printed ASA pads and nylon “cannons”—the black hollow cylinders visible in the photo. Each part and material used serves a purpose. The aluminum ring would be too time-consuming to print from plastic, so it was machined to be lightweight but rigid. The nylon cannons are soft enough to hold the part in place without marring its surface, while the impact-resistant ASA pads provide support.