CPI Aerostructures provides subassemblies almost exclusively for military aircraft.  Having grown from about 20 employees to nearly 300 in a short period of time, the company realized that its ability to meet its custom tooling needs hadn’t kept pace with this growth.

The company’s niche is assembly, work that requires jigs, fixtures, check gages and other custom items. All custom tooling was made by a small tooling department operating manual equipment, or it was farmed out to local machine shops.

To meet ever-increasing demand for custom tooling on the assembly floor, the company chose to add a fused-deposition modeling (FDM) 3D printer to bring more of its tooling work in-house and reduce time and cost of custom tooling.

Producing subassemblies for aircraft has been CPI Aerostructures’ specialty since the company was founded in 1980. Typically working as a subcontractor, CPI sources discrete parts from its global supply chain, fashions them into subassemblies, polishes and paints the assemblies as needed, and ships the finished pieces to the customer or main contractor.

In the past, the company would model the needed jigs and fixtures in-house and then send the design out to external shops, where the lead time was 12-14 weeks for a modest-sized tool that could cost several thousand dollars to $25,000 or more.

CPI added an in-house tooling department in 2012 to help alleviate some of the tooling needs as it grew. But overwhelming maintenance of in-house tooling department pushed the company to seek another solution. So, CPI purchased and installed a Fortus 360mc 3D printer. The FDM system offers a build envelope measuring 14 by 10 by 10 inches (355 by 254 by 254 mm) and enables CPI to print with both polycarbonate and nylon material.

Bringing the printer into the engineering department has dramatically reduced cost and turnaround time for custom tooling. In many cases, tooling can be printed in-house much more cheaply, usually for about 25 percent of the cost of outsourcing it to be machined. 3D printing is also much faster; by batching parts and running the printer overnight, CPI can have a complete tool in-hand in less than a week.

This bonnet for an A10 Thunderbolt aircraft is made of flexible sheet metal, which made it difficult to confirm that the part was good before CPI fixtured it for drilling. A check gage 3D-printed in four parts (right) now makes it possible to quickly check the parts before this stage. (Source: AM Magazine)
CPI can easily check the size and shape of the panel using a portable CMM once it is set up on the welding table. (Source: AM Magazine)

Additive manufacturing is not always the solution to every problem, nor is it always the complete solution. In many cases, the shop uses what he calls “hybrid tooling,” meaning tooling formed from a combination of printed and machined parts, each serving a specific function.

For the fixture for the engine inlet of an Embraer Phenom 300, CPI developed a “hybrid” fixture consisting of a central machined aluminum ring, with printed ASA pads and nylon “cannons”—the black hollow cylinders visible in the photo above. When the part is seated in this fixture, the cannons are flush against its inner diameter where the holes will be drilled. The nylon is soft enough to hold the part in place without marring its surface, and, with the impact-resistant polycarbonate behind it, provides needed support during hole drilling.

This engine inlet for the Embraer Phenom 300 requires a number of large holes to be drilled around its bottom circumference, a process that can cause the metal to buckle or bend. (Source: AM Magazine)

Given the positive impact that CPI has seen over the past few years, the company is now ready to upgrade its 3D printer.  3D printing capability is not necessarily something the company markets to its customers, but those who know about it see its value.

>> Read more by Stephanie Hendrixson, Additive Manufacturing Magazine, 3/29/2017

Aerospace Contractor Brings Custom Tooling In-House with FDM 3D Printing