Analysis of post-processing influence on the geometrical and dimensional accuracy of selective laser melting parts

Abstract

Purpose This study aims to analyze the effect of the different common post-processes on the geometrical and dimensional accuracy of selective laser melting (SLM) parts. Design/methodology/approach An artefact has been designed including cubic features formed by planar surfaces orientated according to the machine axes, covering all the X-Y area of the working space. The artefact has been analyzed both geometrically (flatness, parallelism) and dimensionally (sizes, distances) from coordinate measuring machine measurement results at three stages, namely, as-built, after sand-blasting and after stress-relieving heat treatment. Findings Results from the SLM machine used in this study lead to smaller parts than the nominal ones. This effect depends on the direction of the evaluated dimension of the parts, i.e. X, Y or Z direction and is differently affected by the sandblasting post-process (average erosion ratio of 68, 54 and 9 µm, respectively), being practically unaltered by the HT applied after. Originality/value This paper shows the influence, from a geometric and dimensional point of view, of two of the most common post-processes used after producing SLM parts, such as sand-blasting and stress-relieving heat treatment, that have not been considered in previous research.