Application of the Box-Behnken Design in the Optimization of Laser Powder Bed Fusion of H13 Tool Steel

Parameter optimization is an important step in the laser powder bed fusion (L-PBF), since process defects greatly impact the mechanical properties of the final parts, especially in components that undergo cyclic loading, such as molds and dies. The present study used the H13 tool steel to show that it is possible to perform a good parameter optimization quickly and with relatively few samples. The Box-Behnken experiment design model was used along with the application of the response surface methodology. Laser power, scan speed, and hatch spacing were used as independent variables, and density and porosity were chosen as the response. Power and speed most influenced the responses, but the interaction between power and speed, and power and hatch also had a significant influence. New optimized samples showed lowest porosity, confirming the effectiveness of the model. Density can be used during parameter optimization without impairing the optimization quality.

Keywords:
Tool steel; laser powder bed fusion; additive manufacturing; optimization; Box-Behnken; response surface methodology