Influences of scan strategy and exposure parameters on diameter and surface quality of struts in lattice structures

A modified point-exposure strategy is presented which enables the use of point-exposure on industry-standard laser beam melting systems without modifying its software configuration. Therefore exposure points are replaced by short scan vectors of defined power and scan speed. The influence of the length of the exposure vectors as well as of the laser power and the scan speed on the strut diameter and the surface quality are investigated. It is shown that with this method manufacture of lattice structures which exhibit strut diameters of 150 mm or less and smooth surfaces compared to contour hatch-exposure is possible. Additionally a qualitative comparison of the micro structures of contour hatch-exposed and point-exposed specimens out of Ti6Al4V is carried out. Specimens of both exposure strategies show a similar micro structure.