ORNL and Boeing 3D Print Giant Mold for Aerospace Composite Production

Oak Ridge National Laboratory (ORNL) and The Boeing Co. have successfully 3D printed a nearly 2-ton steel stamp form die (SFD) mold using wire-arc additive manufacturing (WAAM). This mold, designed for thermoplastic composite (TPC) part production, will be used by Boeing in NASA’s Hi-Rate Composite Aircraft Manufacturing (HiCAM) project. The project aims to boost the production rate of composite aircraft while reducing weight to enhance fuel efficiency and lower operating costs.

Traditional SFD molds are made through conventional metalworking methods like machining and casting. The collaboration between Boeing and ORNL explored whether 3D printing a thermally controlled SFD mold could offer advantages in speed, cost, and simplicity. The mold was built over 8 weeks using ORNL’s Arc-1 system, which employs a robotic arm and welding torch to melt wire feedstock. The final print measures 6 feet tall and 4 feet wide, combining mild steel for strength and stainless steel for corrosion resistance and dimensional stability.

One of the main challenges during the printing process was warping due to residual stresses. To address this, the team added temporary support ribs and used computer simulation to refine the design. After 32 simulation iterations, the printed mold was within a few millimeters of its intended shape. The mold was then sent to Baker Industries for annealing, removal of support ribs, and final fabrication to meet Boeing's specifications.

While not all parts of the final tool were 3D printed, ORNL highlights that the technology developed during this project can be replicated for similar tool types. Ahmed Arabi Hassen, ORNL’s group leader for composites innovation, suggests that this success could pave the way for making large thermoplastic structures for other industries, such as energy and automotive.