Experimental approach towards parameter evaluation in laser powder bed fusion of metals

Additive manufacturing is being increasingly focused on the production of end-use parts. Compared to the prototyping application, the production of end-use parts demands a higher level of repeatability and process quality. To achieve this, increased knowledge is required about the influence of various process parameters on the part characteristics and the parameter interrelations. Design of Experiment methods can be applied to gain knowledge on the process behavior, but the applicability of different DoE methods for AM processes has to be validated. This paper describes the application of a definitive screening design for the identification of influencing parameters in Laser Powder Bed Fusion of CoCrW alloy. The impact of various hatch parameters on the part porosity is analyzed. The experimental setup and results are described. The results are validated in an additional test series, comparing the part quality achieved by parameter-sets obtained by different optimization approaches. Furthermore, the correlation of the porosity towards mechanical properties is investigated. Finally, the opportunities and limitations of the method are discussed.