Methodology for integrated additive-subtractive process chain generation
The production share of laser powder bed fusion increases in industrial application and single piece and small series production are core markets. Still, many process steps in the field of additive manufacturing are manually operated, especially in post-processing. Additionally, it is not possible to achieve tight dimensional tolerances or low surface roughness which are necessary for typical mechanical parts. Hence, a process chain has to be set up to combine the design flexibility and function integration capabilities of AM with further machining technologies to achieve workpiece requirements. As L-PBF has some particular properties and process parameters influencing post-processing, an individual approach for process chain generation is needed. These properties and parameters are, in particular, support structures and free positioning options within the build chamber of the AM machine. Both properties have a major influence to post-processing and have to be addressed in machine selection, clamping options, processing steps and workpiece description. The approach shows how an additive manufactured workpiece can be described taking into account the complex part consisting of workpiece, support structures and substrate plate. Further, kinematic limitations for further processing are added as meta-information and workpiece requirements and machine performances are compared for a manufacturing process selection for further processing. Based on technological and economical parameters a manufacturing process selection is performed. Finally, improved parameters are suggested to optimize the L-PBF process with regard to further processing. So, the L-PBF process design can combine AM parameters with further processing parameters to improve the whole process chain. The methodology shall be implemented in a software tool to simplify the practical application.