German research project investigates welding of SLS and injection molded parts

A joint research project funded by the Bavarian Research Foundation is examining the welding of additive manufactured parts to create individualized series components. 

Titled “FAB-Weld”, the three-year project will focus on optimizing welding processes for SLS and injection molding parts, in order to create larger hybrid components. The research is being conducted in response to the demand for large-format SLS 3D printed components, as size is restricted by the dimensions of today’s build chambers. 

Partners of the project include FIT Additive Manufacturing Group, a German 3D printing service provider, the Institute of Polymer Technology (LKT) at FAU University of Erlangen-Nuremberg and German multinational automotive company BMW. FIT will be represented by its subsidiary Sintermask in the FAB-Weld project, which will contribute by providing its expertise in SLS 3D printing. 

Christian Wiesner, responsible for the project at FIT, highlights the significance of the research target, stating that “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.”

Partners of the FAB-Weld project, from left: Christian Wiesner (FIT Additive Manufacturing Group), Tobias Beiss und Juergen Lochner (bielomatik), Prof. Dr.-Ing. Dietmar Drummer (FAU/LKT), Bavarian Minister of Science Bernd Sibler, Prof. Dr. Arndt Bode and Joachim Hornegger (Bavarian Research Foundation). Photo via FAU/Harald Sippel)
Partners of the FAB-Weld project. Photo via FAU/Harald Sippel.

Getting FIT

Founded in 1995, FIT Additive Manufacturing Group has garnered nearly 25 years of experience in the 3D printing industry. The company manufactures prototypes, production tools, 3D printed spare parts, and additively manufactured end-use components for a variety of verticals. It was also the former parent company of Netfabb, a 3D printing software now owned by Autodesk

In 2018, FIT reinforced its SLA 3D printing solutions by installing three ProX 800 3D printers and one ProX 950 3D printer from 3D Systems. Beyond 3D printing, the company also offers services for injection molding, and is therefore equipped with relevant expertise for the FAB-Weld research project.

A spare part additively manufactured by FIT. Photo via FIT.
A spare part additively manufactured by FIT. Photo via FIT.

Optimizing welding processes for large volume plastic SLS parts

SLS 3D printing is suited for manufacturing complex components using thermoplastic materials. Compared to injection molding, SLS technology does not require molds to produce parts. It therefore presents an attractive solution for producing individualized components with high geometrical freedom, however only in small lot sizes.

The FAB-Weld project is specially optimizing welding processes in order to develop a practical solution that overcomes the size limitation of SLS 3D printing. It is looking at joining together customer-specific SLS components and standard injection molding parts, as well as SLS parts with other SLS modules. 

Merging the components together would achieve large-volume parts, however, to do so it requires a high-strength media-impermeable connection. The attachment would ideally utilize the same materials as the conjoined parts as well. 

The research partners have already identified vibration welding and infrared welding processes as promising technologies for assembly. FIT’s role in FAB-Weld will be 3D printing the SLS sample parts. It will also analyze the mechanical properties and behaviour of the welded parts by using its in-house testing and measuring technologies, such as GOM scanning and CT scanning. 

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Featured image shows partners of the FAB-Weld project. Photo via FAU/Harald Sippel.