Additive Manufacturing of Steel and Copper Using Fused Layer Modelling: Material and Process Development

Abstract Fused Layer Modelling (FLM) is one out of several material extrusion (ME) additive manufacturing (AM) methods. FLM usually deals with processing of polymeric materials but can also be used to process metal-filled polymeric systems to produce metallic parts. Using FLM for this purpose helps to save costs since the FLM hardware is cheap compared to e.g. direct metal laser processing hardware, and FLM offers an alternative route to the production of metallic components. To produce metallic parts by FLM, the methodology is different from direct metal processing technologies, and several processing steps are required: First, filaments consisting of a special polymer-metal composition are produced. The filament is then transformed into shaped parts by using FLM process technology. Subsequently the polymeric binder is removed (”debinding”) and finally the metallic powder body is sintered. Depending on the metal powder used, the binder composition, the FLM production parameters and also the debinding and sintering processes must be carefully adapted and optimized. The focal points of this study are as following: 1. To confirm that metallic parts can be produced by using FLM plus debinding and sintering as an alternative route to direct metal additive manufacturing. 2. Determination of process parameters, depending on the used metal powders (steel and copper) and optimization of each process step. 3. Comparison of the production paths for the different metal powders and their debinding and sintering behavior as well as the final properties of the produced parts. The results showed that both materials were printable after adjusting the FLM parameters, metallic parts being produced for both metal powder systems. The production method and the sintering process worked out well for both powders. However there are specific challenges in the sintering process that have to be overcome to produce high quality metal parts. This study serves as a fundamental basis for understanding when it comes to the processing of steel and copper powder into metallic parts using FLM processing technology.