Optimization of hatch spacing for improved build rate and high density preservation in laser powder bed fusion of pure titanium

This study investigated the optimization of hatch spacing to enhance both the build rate and the density of parts produced by laser powder bed fusion of commercially pure titanium. Employing a multi-layer single track experiment, we derived the average width of melt pools, which adjusted hatch spacing to preserve the density of a part, and we proposed a modified build rate having a quadratic function of scanning speed. Nine process conditions were evaluated with a fixed laser power, while varying hatch spacing and scanning speed, to identify optimal conditions that yield a high density and maximize the build rate. The optimal process condition was a laser power of 310 W, scanning speed of 1943 mm/s, and hatch spacing of 106.7 μm. We confirmed that our process condition derived by a modified build equation could achieve higher build rate with a high density over 99.0% than prior studies. It is expected that this approach can be applied for industries requiring a high productivity of LPBF. [Display omitted] •Hatch spacing in laser powder fusion of pure Ti was derived by multi-layer single track experiment and image processing.•Optimization of hatch spacing was performed using modified build rate modeled as a quadratic function of the scanning speed.•The influence of scanning speed and hatch spacing on the microstructures and tensile strength was investigated.•Process condition derived by modified equation achieved higher build rate with density exceeding 99% than previous studies.