Additiv tillverkning i metall och topologioptimering

Sammanfattning: This thesis project was conducted as a case study at Scania CV, a manufacturer of trucks, buses and industrial and marine engines. The project aimed to investigate how topology optimization can be used to design end products for metal additive manufacturing (AM). The main research questions for the project was: How can topology optimization be used to design parts for metal additive manufacturing? Which gave rise to further research questions: Which parts are suitable for metal additive manufacturing? Which factors has to be considered when designing end products for metal additive manufacturing? The main benefits of additive manufacturing revealed in the literature were short lead time, possibility to manufacture complex geometries and consolidate multiple parts into a single part. The applications of metal additive manufacturing found in the literature included prototypes and end products as well as tools and spare parts. Small, complex geometries which are expensive to manufacture traditionally due to expensive tooling or low volumes are most likely to be suitable for metal additive manufacturing. Parts where trade-offs have to be made between manufacturing cost and performance could also be interesting to investigate for AM. The build size of the selected machine is a limiting factor when choosing parts and the build direction of the part, the need for support material during manufacturing and post processing are important to consider when designing parts for metal AM. The case study was performed based on Design for Additive Manufacturing (DFAM), a method for designing parts for AM. DFAM consists of deciding the specifications for the part, consolidate parts if possible, optimize the geometry of the part and make sure it is possible to manufacture. Two parts were optimized with topology optimization during the case study and the resulting geometries were imported to Catia in order to create CAD-models. The results from the case study showed it was possible to automatically create CAD-models based on the resulting geometries from topology optimization. However the automatic CAD-models are not suitable for manufacturing of end parts. But the case study indicates a weight reduction of about 30 % seems to be possible for topology optimization combined with AM even for parts already optimized for low weight but adapted for traditional manufacturing methods. Reducing the overall weight of trucks is important since the carrying capacity is important for customers when choosing vehicles for transportation and the gross vehicle weight is regulated by laws. This makes topology optimization and metal AM a highly interesting area for further investigation. As for now, small, complex parts which are traditionally expensive to manufacture are most likely to be profitable for manufacturing of end parts with metal AM.