A Design Method for SLM-Parts Using Internal Structures in an Extended Design Space

Selective laser melting enables the production of cavities as well as internal structures and thus opens up new lightweight potentials for mechanically loaded components. This paper describes a design method for weight-optimization by applying internal structures in an extended design space compared to conventional models. Based on a pedal crank as a demonstrator, the objective is a maximum weight reduction with predefined stresses and a homogeneous stress distribution. The basic dimensioning of the design space is limited by assembly and application restrictions. By using computer aided design tools and topology optimization in an iterative procedure, a step wise confinement of the design space takes place. Concerning the same interfaces and functions as the conventional pedal crank, new model generations with the advantage of force flow adapted structures are built up. Using Finite Element Method, a continuous evaluation of the impact from a change of design towards the weight/stress ratio is performed. The created models are evaluated regarding their weight reduction in order to select the most efficient one. The final model has a large-volume geometry with the simultaneous integration of internal structures and cavities. A validation compared to the initial model as well as to a model with conventional design space and selective areas with internal structures quantifies the optimization result. Based on the acquired knowledge from this comparison, an estimation of the weight reduction potential concerning the design method is given.