Improved Machining of Additive Manufactured Workpieces Using a Systematic Clamping Concept and Automated Process Planning

High requirements for functional surfaces of additive manufactured workpieces result in a required post-process machining. Multiple clamping set-ups as well as the manufacturing of specific clamping devices are currently needed for the machining of complex parts. The process and its planning is not highly automated and requires a lot of manual effort. Hence, the automation level and effectiveness of post-processing have to be increased. This means that machining has to be considered at an early stage of the process chain. Integrated workpiece-structures, the so-called tooling-points, provide the possibility of defined clamping and referencing. By using them, the precise finishing of individual products is realizable by simply using conventional clamping systems. In this paper, an innovative and systematic tooling-point design concept is shown, which has been developed using results obtained in experimental investigations on the machining of additive manufactured parts. Additionally, a method for an automated process planning was developed in which a consistent data format of the extended process chain of additive manufacturing was used. Additive manufactured TiAl6V4 free-form parts with attached tooling-points were used for the validation of the whole process chain. The finishing process, including the removal of support-structures, was carried out on a CNC milling-machine. This paper shows the development and experimental validation of a tooling-point concept that provides the possibility of defined clamping and referencing using conventional clamping systems. The results will be included in a data-preparation tool, which allows the user to consider possible tooling-points at early construction level. Furthermore, the realization of an automated machining process including an optimized process planning method is shown.