Case Study - A New Kind of "Power" Tool: How Siemens Gas & Power Supports Production with Additively Manufactured Tooling

The Challenge

Siemens Gas & Power manufactures world-class gas turbines for industrial power generation and mechanical drive applications. Used for a variety of applications, including turn-key power station projects, Siemens power systems are frequently tailored for each customer project. One such area of customization is the fuel type used to power the gas turbine.

Siemens is also a pioneer in the field of additive manufacturing and has been driving its industrialization for over a decade. In 2012, they opened their first designated 3D printing workshop for serial manufacturing, repairs, and prototyping of metal components. The workshop is located Finspång, Sweden, as an integral part of the gas turbine manufacturing business.

Recently the Siemens engineers in Finspång began 3D printing a specially designed fuel injector nozzle to react quickly to customers' customization requirements. They found that conventional methods of manufacturing were hindering the team from achieving higher customer benefits.

By additively manufacturing the fuel injector nozzles, the engineers were able to fabricate high-performing, complex parts faster than before. However, they also realized that the more intricate the 3D printed custom nozzles became, so too did the post-production machining. The necessary support structure required to 3D print the nozzle had to be milled away afterwards, and a special fixture had to be designed to do this. Conventional tooling could not reliably hold the nozzles without causing damage due to the thin, geometrically obscure nature of the nozzle walls. To outsource the geometrically complex, custom tooling would drive up lead time significantly.

The Solution

The fixture allowed the Siemens technicians to clamp the geometrically complex fuel nozzle for machining on their 5-axis mill. As the metal part's walls were quite thin, they were concerned that the fuel nozzle might flex under machining loads. However, since the Markforged-printed fixture was printed in Onyx — a nylon-based thermoplastic filled with chopped carbon fiber — the fuel nozzle could be clamped without it vibrating within the conformal fixture. The composite workholding has transformed the fuel injector nozzle from a machining challenge to an asset. The team is impressed with the quality and stiffness of the fixtures. "It's absolutely a lean tool," says Graichen of the X7. Fagertoft agrees, "The material itself is thoroughly impressive in terms of strength."

Looking Ahead