Build accuracy and compression properties of additively manufactured 304L honeycombs

Abstract

Purpose The purpose of this study is to analyze the build quality and compression properties of thin-walled 304L honeycomb structures manufactured by selective laser melting. Four honeycomb wall thicknesses, from 0.2 to 0.5 mm, were built and analyzed. Design/methodology/approach The density of the honeycombs was changed by increasing the wall thickness of each sample. The honeycombs were tested under compression. Differences between the computer-assisted design model and the as-built structure were quantified by measuring physical dimensions. The microstructure was evaluated by optical microscopy, density measurements and microhardness. Findings The Vickers hardness of the honeycomb structures was 209 ± 14 at 50 g load. The compression ultimate and yield strength of the honeycomb material were shown to increase as the wall thickness of the honeycomb samples increased. The specific ultimate strength also increased with wall thickness, while the specific yield stress of the honeycomb remained stable at 42 ± 2.7 MPa/g/cm3. The specific ultimate strength minimized near 0.45 mm wall thickness at 82 ± 5 MPa/g/cm3 and increased to 134 ± 3 MPa/g/cm3 at 0.6 mm wall thickness. Originality/value This study highlights a single lightweight metal structure, the honeycomb, built by additive manufacturing (AM). The honeycomb is an interesting structure because it is a well-known building material in the lightweight structural composites field but is still considered a relatively complex geometric shape to fabricate. As shown here, AM techniques can be used to make complex geometric shapes with strong materials to increase the design flexibility of the lightweight structural component industry.