FIT Additive Manufacturing Group examines welding processes for SLS and injection molded parts

Large-format SLS components are sought after. However, size still is restricted by the given size of today’s build chambers. The joint research project FAB-Weld now focuses on the welding of additively manufactured parts to create individualized series components. Funded by the Bavarian Research Foundation, the project pursues the goal of optimizing welding processes for plastic materials. Among the project partners are the Institute of Polymer Technology (LKT) at FAU University of Erlangen-Nuremberg, the FIT Additive Manufacturing Group and BMW.

FIT Additive Manufacturing Group, represented by its subsidiary Sintermask, will contribute to the project by sharing its long-term expertise in Selective Laser Sintering (SLS). SLS is an ideal technology to manufacture complex components from thermoplastic material. When compared to conventional technologies such as injection molding, SLS scores by its avoidance of costly molds which makes SLS an economical alternative to produce individualized components of high geometrical freedom in small lot sizes.

The project FAB-Weld now is looking for practical solutions to compensate for the size limitation by specially optimized welding processes. When joining customer-specific SLS parts and standard injection molded parts, as well as SLS parts with other SLS modules to achieve large-volume parts, this requires a high-strength, media-impermeable connection which best uses the same material as the actual parts. Vibration welding and infrared welding have been identified as promising assembling technologies beforehand. FIT will manufacture SLS sample parts and will determine mechanical key figures by analyzing the mechanical properties and behavior of the welded parts with the help of testing and measuring technologies available in-house such as GOM scanning and CT scanning. The project will have a three-year term.

Christian Wiesner, responsible for the project at FIT, underlines the importance of the research target when he says, “We simply don’t have any intelligence about high-strength welding of SLS parts, so this is a great opportunity to investigate very basically the processes of welding SLS parts. The findings will be a significant benefit for the further development of AM regarding SLS technology.”