A lattice structure coupon sample for build quality control in metal additive manufacturing

Abstract

Quality control in Additive Manufacturing (AM) is vital, as process parameters can lead to defects, impacting mechanical properties. The present study proposes the use of a lattice structure coupon sample as a proxy for build quality control. Lattices are sensitive to variations in process parameters, impacting the resulting mechanical properties, more so than bulk mechanical test specimens. The sensitivity of lattice structures allows for the detection of subtle changes in process parameters, which can be valuable for quality control efforts, i.e. maintaining constant manufacturing quality. In this study, a series of lattice coupon samples were manufactured with varying factors as a proof of concept to demonstrate this concept. Non-destructive micro-computed tomography (CT) was used to quantify the manufacturing variations/defects. The lattice coupons are subjected to quasi-static compression testing to evaluate their mechanical properties, with differences shown indicative of changes in the manufacturing process. The work reported here acts as a proof of concept for a low-cost build quality evaluation methodology using lattice coupons and compression testing alone. When the build quality deteriorates or parameters change without the knowledge of this by the operator, this will be observed in changes in the compressive test results for lattice coupons.

Keywords

• Build quality control
• Process parameter
• Lattice structure
• Coupon sample
• Mechanical testing