Additive manufacturing allows complexity of manufactured structures, allowing entirely new design capabilities. In the context of complex structure design, lattice structures hold the most promise for high complexity, tailorable and ultra-lightweight structures. In medical applications, these structures find application especially in bone implants – allowing matching of local elastic modulus of implant to that of bone and also allowing osseointegration. With this new complexity comes new manufacturing quality control and metrology challenges. Traditional metrology tools cannot access the entire structure and the only reliable method to inspect the inner details of these structures is by X-ray tomography. This work highlights the challenges of this process, demonstrating a workflow for dimensional metrology of coupon lattice samples. The confidence gained by inspection of such lattice coupons support the application of these lattices in end-use parts. The same principles are applied to larger samples and limitations are discussed using examples of implants.
Professor du Plessis is a researcher with more than 20 years of academic experience (15 years post-PhD). He is academically ranked as Associate Professor (Physics Department) and manages an interdisciplinary research centre for X-ray micro computed tomography – the Stellenbosch CT facility. He is associated with the newly established Institute for Biomedical Engineering and also with the Nelson Mandela University in an honorary research position. Nationally and internationally he collaborates widely, also working closely with industry partners. His research interests are in Additive Manufacturing, X-ray Tomography and Biomimicry. In his most recent research, he focuses on structural integrity in metal laser powder bed fusion and works on studies of lattice structures (extreme lightweight “scaffold” structures) through a funded project of the South African Collaborative Program in Additive Manufacturing (CPAM). He is associate editor of the highest impact-factor journal in this field – Elsevier’s Additive Manufacturing journal (IF = 7.2).