Evaluation of productivity in laser sintering by measure and assessment of geometrical complexity

Abstract

Purpose In additive manufacturing (AM), “complexity for free” is often cited as a major technological benefit. This generalized view has been found inaccurate by several authors dealing with the evaluation of part complexity. However, the term “complexity” is not defined uniformly. The reasons for this are the various AM processes and different evaluation factors used by the respective authors. This is critical because build time heavily depends on the impact of complexity on the additive process through the processing tool (point-to-point-, line- and mask-based) defining competitiveness. This study aims to define appropriate complexity indicators and evaluate the impact on productivity of PBF-LB/P (laser sintering). Design/methodology/approach An assessment methodology for geometric complexity is developed for point-to-point-based processes using the PBF-LB/P process. First, an overview of part characteristics and their interrelationships with the generation process is provided. In this way, relevant factors, e.g. part volume and perimeter length, are identified. Subsequently, these are used to create a metric to select and manufacture test samples to quantify the impact on build time. Findings The results indicate a strong impact of geometrical complexity on build time and build-up rate. Consequently, optimizing the geometry in the early design stage and adjusting process parameters during production planning allow to influence the build-up rate. Originality/value This paper demonstrates the effects of geometric complexity using manufacturing jobs. As a result, the suitability of existing methods and KPIs is shown to be insufficient. Hence, meaningful indicators for laser sintering, such as contour length vs hatch length, contour length vs part volume and number of hatches vs part volume, are defined and verified.