Structure function analysis of powder beds in additive manufacturing by laser beam melting

Abstract

Additive manufacturing and specifically laser-based powder bed fusion processes of metals show a rapidly increasing demand in production technology. One key parameter that impacts the quality of the finished part is the condition of the powder bed. It is not surprising that the uniformity of the metal powder distribution has a great influence on the process stability. Caused by the recoating system, the powder may have uneven roughness or unwanted structures such as waviness. One consequence of these conditions may be for example that the fabricated structure contains porosity. In this paper we are proposing an instrument to detect powder bed irregularities in-process, using the so-called structure function. The dimensional data of the powder bed surface can be rapidly evaluated and, moreover, relevant parameters can be obtained with this statistical tool, allowing for in- or off-line process assessment.