Browsing by Author "Park, M"
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- ItemUsing a lattice structure coupon sample for build quality monitoring in metal additive manufacturing.(Stellenbosch : Stellenbosch University, 2023-11) Park, M; Du Plessis, A; Venter, MP; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: Additive manufacturing (AM), particularly Laser Powder Bed Fusion (L-PBF), has revolutionised the manufacturing industry by offering enhanced geometrical design freedom, part integration, and reduced production lead time. However, the presence of manufacturing defects during the L-PBF process poses challenges to the mechanical properties and build quality of the manufactured parts. Traditional quality assessment methods involve costly and time-consuming manufacturing, destructive or non-destructive analysis and mechanical testing. To address these challenges, this research proposes a novel approach for quality control using lattice coupon samples instead of solid mechanical test specimens. Lattice structures, comprising repetitive unit cells with struts and nodes, serve as effective indicators of build quality. The smaller size and volume of the lattice coupon samples result in significant cost and time savings compared to traditional test samples. The high sensitivity of lattices to parameter deviations enables their use in assessing build quality within an L-PBF system. These coupon samples provide reliable indicators of structural integrity and long-term performance of AM parts, simplifying the quality control process and optimising L-PBF manufacturing. Additionally, this research develops a Finite Element (FE) model for AM lattice structures under quasi-static compression, offering a powerful tool for the virtual testing of components, enabling the study of their mechanical behaviour without the need for costly physical prototypes. The FE model incorporates defect states of the AM lattice structures observed from computed tomography (CT) scanning. By taking input from the CT scans, the prediction of mechanical properties of lattices with a high accuracy rate of 83 % was achievable. This model represents a promising tool for developing manufacturing defect-incorporated lattice representative volume elements (RVEs) for use in the design of AM parts incorporating lattice regions. By replacing complex lattice structures with solid-infilled features in the form of RVEs in simulations, the computational expense can be significantly reduced. This approach allows for efficient exploration of the mechanical behaviour of latticed AM components while accounting for manufacturing defects, offering insights for design optimisation and material selection. Furthermore, this research aims to leverage the developed FE model and interpolation methods to predict the mechanical properties of lattice structures, reducing the reliance on physical printing and CT scanning. By utilising these computational tools, accurate estimations of the mechanical properties can be achieved, minimising the need for extensive experimental testing and CT scan. Overall, this research contributes to the advancement of quality control in AM by introducing lattice coupon samples as indicators of build quality and developing computational models for predicting their mechanical properties. These innovations lead to improved efficiency and optimisation of L-PBF manufacturing processes, benefiting industries that rely on AM technology.