Challenges Of Production Planning And Control For Powder Bed Fusion Of Metal With Laser Beam: A Perspective From The Industry

Due to technological advance, the Additive Manufacturing (AM) technology Powder Bed Fusion of Metal with Laser Beam (PBF-LB/M) is in widespread industrial use. PBF-LB/M offers the flexibility to generate different geometries in one build job independent of tools. Therefore, exploiting tool-dependent economies of scale is not required for efficient manufacturing of various complex geometries in small quantities. However, PBF LB/M production lines are capital intensive and include post-processing steps. Thus, high utilization and low work in process must be ensured to minimize costs, but reaching high utilization contradicts minimizing work in process and throughput time. In production planning and control (PPC), the trade-off between those production logistics key performance indicators (KPIs) is optimized. The advantage of flexibility to manufacture various geometries in one build job of PBF-LB/M comes with challenges for PPC. In this work, those challenges are analysed to derive implications for improvement, based on interviews with experts from the industry. Results show a need for PBF LB/M specific PPC. The need is higher the greater the technological control of PBF LB/M and the volume of a product program of a company are. Unlike for Conventional Manufacturing (CM), nesting and scheduling cannot be addressed separately in PPC for PBF LB/M. Thus, the optimization of production logistics KPIs is more complex due to more degrees of freedom. Combined with a typically shorter planning horizon for AM, this requires automated optimization software tools for combined nesting and scheduling. Currently, PPC that considers AM characteristics does not address CM steps in the post-process adequately, even though they cause a large proportion of effort and time. Furthermore, high automatization parallel to heterogenous manual tasks require a low number of workers with training in various skills

Development of a Comparative Assessment Method For Additive and Conventional Manufacturing With Regard to Global Warming Potential

Additive Manufacturing (AM) opens new possibilities for producing complex parts while achieving high material efficiency. Besides the technological advantages, AM is considered a key technology for sustainable production. A widely used approach to measure the sustainability of a product is the Life Cycle Assessment (LCA) by using the impact category of the Global Warming Potential (GWP). The setup of LCA is complex and requires a deep understanding of the process. LCAs carried out so far for AM mainly focused on energy consumption and the printing process itself. GWP caused by other up and downstream manufacturing steps, such as material preparation, has received little attention so far. This requires more comprehensive LCAs, increasing the complexity and effort. Therefore, the GWP is often not considered when deciding whether to use AM or Conventional Manufacturing (CM) for producing a part in the industry. This work presents a simplified method (GWP-method) for comparing AM and CM regarding the GWP by identifying so-called hotspots (the most significant production steps in terms of GWP). Based on the identified hotspots, the assessment scope was narrowed down, and an Assessment Equation (GWPAE) was developed. The GWPAE can then be used for the analysis of produced GWP for other product families and production scenarios for the defined process route. The method is demonstrated for an aerospace part as a case study. Finally, the deviation of the derived GWPAE is checked by directly comparing the results of the GWP of an LCA for another production scenario and lies at 5,9%