Oak Ridge National Laboratory and Boeing used wire-arc metal printing to produce a nearly 2-ton forming tool for thermoplastic aircraft parts, with curved internal channels for heating and cooling. Boeing will use the tool in its contribution to NASA’s Hi-Rate Composite Aircraft Manufacturing project.
The stamp-form die presses heated thermoplastic composite between metal molds to shape aircraft parts such as doors. Conventional versions are made through machining, casting, forging and drilling. For this tool, ORNL’s Arc-1 robotic system deposited metal wire layer by layer; the process is called wire-arc additive manufacturing.
The printed form combines mild steel in its structure with stainless steel at the working surface. Its heating and cooling channels curve along the mold’s shape instead of running straight through it, as is typical for drilled passages. ORNL says the design improves thermal control, but the announcement reports no measured cycle-time gain.
As the deposited metal cooled, residual stress threatened to warp the large tool. The team added temporary support ribs and ran 32 design-simulation iterations; ORNL says the printed shape came within a few millimeters of its target. Baker Industries then annealed it to relieve internal stress, removed the ribs and completed the remaining fabrication to Boeing’s requirements. ORNL says the project took eight weeks and notes that not every part of the finished tool was printed.
ORNL describes the die as a test case, and the release provides no cost or cycle-time comparison with conventionally made tools. Boeing plans to use it in NASA’s HiCAM program, which aims to increase composite-aircraft manufacturing rates.
Sources
- Oak Ridge National Laboratory: Partnership between ORNL, Boeing advances manufacturing for aircraft parts
- NASA: Hi-Rate Composite Aircraft Manufacturing project
- Oak Ridge National Laboratory: Copyright status and requested image credit
Lead image: Courtesy of Oak Ridge National Laboratory, U.S. Department of Energy.