Optimization and re-design of a metallic riveting tool for additive manufacturing—A case study

Abstract

This paper discusses the topology optimization and additive manufacturing (AM) specific re-design of a metallic C-frame as it is used in the riveting process in the automotive industry. The main objective of the optimization and re-design process is the reduction of the structural weight where special attention needs to be paid to the specific manufacturing process of powder bed fusion which is a powder based layerwise additive manufacturing process. The initial optimization and AM specific re-design are performed under consideration of a number of free parameters that drive the performance and weight of the C-frame, and several generated solutions are compared under special consideration of the weight, the mechanical performance and the general manufacturability using powder bed fusion. The selected optimized solution then undergoes a final detailed re-design which focusses on given manufacturing restrictions. The mechanical performance of the optimized C-frame is assessed employing detailed finite element simulations by evaluating the stress and deformation state. The general manufacturability of the optimized part by powder bed fusion is demonstrated by the manufacturing of a scaled prototype. In order to enable a comparison of the new AM solution with a classical manufacturing process, an optimized C-frame geared towards classical milling is established as well. Both solutions are compared concerning weight, mechanical performance, manufacturability and economic aspects, and it can be shown that the AM solution offers a number of advantages that cannot be exploited when employing classical means of manufacturing. This paper may serve as an introduction to the rather complex field of AM design of load bearing structures and is an illustrated case study thereof which can be of use for engineers working in this specific field that is still the topic of global academic and industrial research.