Anton Du Plessis

• PhD
• Comet Technologies Canada Inc

X-ray microcomputed tomography (microCT) has become an established method of testing and analyzing additively manufactured parts in recent years, being especially useful and accurate for dimensional measurement and porosity analysis. While this nondestructive analysis method is gaining traction among additive manufacturing (AM) researchers and engi...

Albert Einstein once said “look deep into nature, and then you will understand everything better”. Looking deep into nature has in the last few years become much more achievable through the use of high-resolution X-ray micro-computed tomography (microCT). The non-destructive nature of microCT, combined with three-dimensional visualization and analy...

Metal additive manufacturing involves manufacturing techniques that add material to produce metallic components, typically layer by layer. The substantial growth in this technology is partly driven by its opportunity for commercial and performance benefits in the aerospace industry. The fundamental opportunities for metal additive manufacturing in...

Additive manufacturing of industrially-relevant high-performance parts and products is today a reality, especially for metal additive manufacturing technologies. The design complexity that is now possible makes it particularly useful to improve product performance in a variety of applications. Metal additive manufacturing is especially well matured...

This review article summarizes the current state-of-the-art for biomimicry in additive manufacturing. Biomimicry is the practice of learning from and emulating nature - which can be increasingly realized in engineering applications due to progress in additive manufacturing (AM). AM has grown tremendously in recent years, with improvements in techno...

The use of X-ray computed tomography (XCT) has seen significant growth over a broad range of disciplines including biology, earth science, engineering, and many more. It is now increasingly used in additive manufacturing (AM) since its benefits are being appreciated more widely. This is due to the method being non-destructive and comprehensive, pro...

In this study, the microstructure and defects of an Al-Mn-Mg-Zr alloy produced by the Powder Bed Fusion–Laser Beam (PBF-LB) technology are investigated. The influence of the process parameters on the microstructure and defects is demonstrated. Aluminum alloys are usually prone to cracking during solidification. However, finding the optimal paramete...

The metastable β-Ti21S alloy exhibits a lower elastic modulus than Ti-6Al-4V ELI while maintaining high mechanical strength and ductility. To address stress shielding, this study explores the integration of lattice structures within prosthetics, which is made possible through additive manufacturing. Continuous adhesion between the implant and bone...

Additive manufacturing is increasing in popularity and several manufacturing industries are adapting to the technology. This is due to the benefits of the process such as allowing for complex designs using a variety of materials. However, the occurrence of defects such as porosity in the manufacturing process remains a major concern and an active a...

Presentation slides for the ISTFA 2024 Tutorial session “AI-Driven Advancements in Image Processing, Analysis and 3D Modeling for Fault Isolation and Failure Analysis.”

In semiconductor manufacturing, the process of laser dicing can result in a loss of yield due to defects associated to the laser interaction with the sample. These defects can be difficult to identify, especially before a proper tuning of the process. Traditional investigation methods, like infrared (IR) inspection and focused-ion beam scanning ele...

Three‐dimensional (3D) printing is an innovative manufacturing method for preparing designer materials with complex geometries. However, there are very few studies on the fabrication of antimicrobial polymer materials suitable for use in everyday clinical objects, via 3D printing. In this work, an antibacterial polymer material is prepared by blend...

The prevalent reliance on expensive, time-consuming CT (Computed Tomography) scans and traditional mechanical testing presents significant challenges in determining the mechanical properties of additively manufactured (AM) metallic lattices fabricated through laser powder bed fusion (L-PBF). This work integrates CT-scan data with finite element mod...

In this study, we examined the impact of process parameters on the manufacturing defects in micro-strut lattice structures produced via Laser Powder Bed Fusion (L-PBF). By intentionally varying parameters like laser power and layer thickness, we investigated how these changes affect internal pores, surface roughness, and geometry discrepancies. To...

In this study, we examined the impact of process parameters on the manufacturing defects in micro-strut lattice structures produced via Laser Powder Bed Fusion (L-PBF). By intentionally varying parameters like laser power and layer thickness, we investigated how these changes affect internal pores, surface roughness, and geometry discrepancies. To...

Spinal interbody fusion cages are commonly used to treat various spinal conditions, but their traditional manufacturing methods have limitations in customization and fitting. With the advancement of 3D printing, it is now possible to design and manufacture interbody fusion cages with previously unachievable features and structures. Southern Medical...

Metal additive manufacturing (AM) is growing rapidly towards industrial adoption in various industries, but porosity remains a concern because it creates areas of stress that affects the mechanical properties and reduces reliability. Porosity can be quantified by X-ray computed tomography (XCT), but the method is relatively slow and expensive. The...

Finite element (FE) modeling is a powerful tool for the virtual testing of components, especially for high-value manufacturing like additive manufacturing (AM). AM often involves lattice structures in parts, imparting unique mechanical properties. Numerical models allow for cost-effective virtual testing, but computational limitations hinder compre...

Additive manufacturing allows the production of complex and custom designs including lattice structures—porous metallic structures with designed porosity and tailored mechanical properties. The bulk material has a key influence on the eventual properties of the porous lattice structure material. Among metallic biomaterials, beta-titanium alloys are...

Volume 24A provides a comprehensive review of additive manufacturing (AM) design fundamentals and applications. The primary focus of the Volume is on metallic systems with limited emphasis on polymers and ceramics where applicable. The first five divisions provide an in-depth review of each of the key aspects of the entire AM value chain. The mater...

Volume 24A provides a comprehensive review of additive manufacturing (AM) design fundamentals and applications. The primary focus of the Volume is on metallic systems with limited emphasis on polymers and ceramics where applicable. The first five divisions provide an in-depth review of each of the key aspects of the entire AM value chain. The mater...

The design of a functionally graded porous structure (FGPS) for use in prosthetic devices is crucial for meeting both mechanical and biological requirements. One of the most commonly used cellular structures in FGPS is the triply periodic minimal surface (TPMS) structure due to its ability to be defined by implicit equations, which allows for smoot...

Functionally graded porous structures (FGPSs) are attracting increasing interest in the manufacture of prostheses that benefit from lower stiffness and optimized pore size for osseointegration. In this work, we explore the possibility of employing FGPSs with auxetic unit cells. Their negative Poisson's ratio was exploited to reduce the loss of conn...

In the recent years, laser powder bed fusion of aluminum alloys has attracted extensive attention due to their capacious application in the biomedical, aerospace, and other industrial sectors. This is due to the combined capabilities of the laser powder bed fusion process and aluminum alloys bringing about complex shapes with high performance assoc...

Diamonds can form within eclogite (remnants of ancient subducted oceanic crust) in the subcontinental lithospheric mantle (SCLM), pieces of which may then be transported to the surface as xenoliths in kimberlites. These diamond-bearing xenoliths offer a rare opportunity to study diamonds in their host lithology. The morphology and surface features...

Over the past few years, numerous advances have been made in X-ray imaging technology. X-ray imaging plays an important role in the non-destructive exploration of the internal structures of objects for research, medical and industrial applications. When X-rays are used in computed tomography (CT), the differences in density of various components of...

Metal additive manufacturing is a fast-growing manufacturing technology for producing components with complex geometries and in short lead times. The widely used Ti6Al4V alloy has particularly good strength to weight ratio while having properties suitable for aerospace and medical industries. The additive manufacturing processes all involve layer b...

For many biological systems different strategies, morphologies and/or behaviours have evolved in response to similar functional demands (a concept known as convergent evolution). The biodiversity on Earth thus holds a wealth of natural strategies that may provide tailored solutions to the social, economic and environmental challenges the world face...

The combined benefit of both additive and subtractive manufacturing within the same gantry system enables hybrid directed energy deposition to create complex geometries with smooth surface finish and superior dimensional accuracy. Moreover, with layer-by-layer access to the structure during both the addition and subtraction of material, the inserti...

Objective: To examine early Homo sapiens fossils from the Late Pleistocene site of Klasies River Main Site, South Africa for evidence of hypercementosis. The specimens represent seven adult individuals dated to between 119,000 and 58,000 years ago. These observations are contextualized in relation to the incidences of hypercementosis among recent...

Image-Based Simulation (IBSim) is the process by which a digital representation of a real geometry is generated from image data for the purpose of performing a simulation with greater accuracy than with idealised Computer Aided Design (CAD) based simulations. Whilst IBSim originates in the biomedical field, the wider adoption of imaging for non-des...

This chapter provides the first descriptions of the intact paranasal sinuses of the Hofmeyr cranium, which include both frontal sinusesFrontal- sinus and the right maxillary sinusMaxillary sinus, and compares these structures across Recent and fossil Homo sapiens. In comparison to Recent human samples, the Hofmeyr cranium presents with absolutely a...

Metal additive manufacturing of titanium and its alloys can produce complicated geometries cost-effectively while maintaining biocompatibility. It is known that the material property differences between bone and Ti6Al4V cause stress shielding, leading to bone failure around the implant. Using lattice structures is effective at reducing elastic modu...

The fatigue behaviour of as-built parts produced by means of Laser-Powder Bed Fusion process (L-PBF) is primarily influenced by the presence of stress raisers on the surface, whose morphology strongly depends on the relative orientation between the surface and the build direction. This study aims to shed light into the factors representing the surf...

Our current understanding of the spectrum of TB and COVID-19 lesions in the human lung is limited by a reliance on low-resolution imaging platforms that cannot provide accurate 3D representations of lesion types within the context of the whole lung. To characterize TB and COVID-19 lesions in 3D, we applied micro/nanocomputed tomography to surgicall...

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species’ holotypes and other key individuals with extant hominids....

‘Scaloposaurs’ represent a wastebasket taxon of small therocephalian therapsids once believed to be close to the evolutionary ancestry of mammals. The group is now thought to be made up of mostly paedomorphic or juvenile therocephalians belonging to various families. Here, a new large therocephalian is described from the Early Triassic Lystrosaurus...

In recent years, laser powder bed fusion of aluminum alloys has attracted extensive attention due to their capacious application in the biomedical, aerospace, and other industrial sectors. This is due to the combined capabilities of the laser powder bed fusion process and aluminum alloys bringing about complex shapes with high performance associate...

The combined benefit of both additive and subtractive manufacturing within the same gantry system enables hybrid directed energy deposition to create complex geometries with smooth surface finish and superior dimensional accuracy. Moreover, with layer-by-layer access to the structure during both the addition and subtraction of material, the inserti...

The functional significance of osteoderms—bony elements embedded in the dermis—remains a topic of much debate. Although many hypotheses have been put forward in the past, the idea that osteoderms can serve as calcium reservoirs has received little experimental attention thus far. In this study, we use micro-computed tomography to investigate inter-...

Additive manufacturing (AM) components can benefit medical applications by improving their functionality and/or providing well fit custom designs. Metal and polymer AM potential can be perfectly expanded to composite materials, such as metal-ceramics, polymer-ceramics, polymer-metal, etc. These components have unique properties that can be benefici...

Here we provide the first phylogenetic analysis that include Afrogecko ansorgii and a detailed morphological comparison with other species of leaf-toed geckos. For this purpose, we used two mitochondrial (16S, ND2) and four nuclear (RAG1, RAG2, CMOS, PDC) genes to produce a robust phylogenetic reconstruction. This allowed us to show that A. ansorgi...

Titanium is a versatile biocompatible metal that is desirable in additively manufactured medical implant devices. However, additively manufactured parts have particular microstructures, porosity, residual stress, and surface conditions which can have a strong impact on fatigue performance. Implants have an added complexity from the saline operating...

Additively manufactured (AM) lattice structures are applied in high-value applications such as lightweight aerospace design and biomedical implants. However, uncertainties of the geometry of as-manufactured AM lattice structures results in uncertainties in the associated mechanical response. This research proposes a non-destructive digital-twin cer...

Elements fabricated by extrusion-based 3D concrete printing (3DCP) display anisotropic mechanical properties when subject to loading conditions orientated in principle cartesian axis directions. Various studies show that the mechanical characteristics of 3DCP components are lower than their mould-cast counterparts, reportedly due to the existence o...

The hardened-state mechanical characteristics of 3D printable concrete (3DPC) mixtures exhibit a strong dependence on the employed extrusion-based process, material, and design parameters and are predominantly anisotropic by nature. It has been shown that at the heart of the observed mechanical anisotropy lies the microstructural morphology of the...

Laser powder bed fusion (LPBF) is receiving widespread attention for its capability to build components with complex geometries. Post-processing can address the adverse effects of various imperfections exhibited in LPBF parts in their as-built state, including inhomogeneous microstructure, tensile residual stresses and poor surface quality. In a re...

Additive manufacturing is a manufacturing technology that has grown from prototyping applications to the production of end-use parts in various industries. It is today possible to produce complex-shaped parts such as cellular or lattice structures in various popular metal alloys relevant to engineering applications. These intentionally designed por...

Beautiful and functional—the perfect combination of nature’s beauty and engineering functionality–best describes the synergy between biomimicry and additive manufacturing. Nature has proven to be a valuable source of inspiration for design solutions with many success stories, yet critical gaps between biological and engineering domains prevent biom...

Nature provides an infinite source of inspiration for innovative designs that may be required to tackle the social, economic, and environmental challenges the world faces. Despite the surging popularity and prevalence, the discipline of bioinspiration is limited in unleashing its full potential by the inadequate understanding of biological and evol...

Additively manufactured surface roughness is an inherent aspect of the process that is known to influence especially the fatigue performance of additively manufactured parts. Postprocessing is often used to improve the surface, but this is not always possible with complex shaped parts such as biomimetic and topology optimized or lattice parts, for...

Titanium is a versatile biocompatible metal that is desirable in additively manufactured medical implant devices. However, additively manufactured parts have particular microstructures, porosity, residual stress and surface conditions which can have a strong impact on fatigue performance. Implants have an added complexity from the saline operating...

Additive manufacturing (AM) of metal components is increasingly used in high performance applications, especially in the aerospace industry. Laser powder bed fusion (L-PBF) of metals is the most widely used and mature process for this purpose, but it comes with some challenges. One of these challenges involves manufacturing quality and associated m...

In recent years, laser powder bed fusion of aluminum alloys has attracted extensive attention due to their capacious application in the biomedical, aerospace, and other industrial sectors. This is due to the combined capabilities of the laser powder bed fusion process and aluminum alloys bringing about complex shapes with high performance associate...

Additive manufacturing (AM) refers to a collection of manufacturing methods involving the incremental addition of material to build a part directly in its final or near-final geometry, usually in a layer-by-layer process. Metal AM in particular has seen great industrial adoption and maturation. This technology enables increased freedom of design in...

Additively manufactured lattice structures of titanium alloys, especially Ti6Al4V, are widely studied for their use in bone replacement implants. The porous nature of these lattice structures reduces the effective elastic modulus and hence can be matched to that of bone, in order to reduce stress shielding effects and allow long-term bone in-growth...

X-ray computed tomography (CT) can reveal the internal details of objects in three dimensions non-destructively. In this Primer, we outline the basic principles of CT and describe the ways in which a CT scan can be acquired using X-ray tubes and synchrotron sources, including the different possible contrast modes that can be exploited. We explain t...

Demand for the construction of new structures is increasing all over the world. Since the construction sector dominates the global carbon footprint, new construction methods are needed with reduced embodied carbon and high resource efficiency to realize a sustainable future. In this direction, Metal Additive Manufacturing, also known as 3D printing...

Polyetheretherketone (PEEK) has been the focus of substantial additive manufacturing research for two principal reasons: (a) the mechanical performance approaches that of aluminum at relatively high temperatures for thermoplastics and (b) the potential for qualification in both the aerospace and biomedical industries. Although PEEK provides outstan...

Recently, there has been an increasing interest on the sustainability advantage of 3D concrete printing (3DCP), where the original cement-based mixtures used for printing could be replaced or incorporated with environmental-friendly materials. The development in digital modeling and design tools also creates a new realm of form-finding architecture...

The fatigue performance of additively manufactured auxetic meta-biomaterials made from commercially pure titanium has been studied only recently. While certain assumptions have been made regarding the mechanisms underlying their fatigue failure, the exact mechanisms are not researched yet. Here, we studied the mechanisms of crack formation and prop...

Laser powder bed fusion (LPBF) as an additive manufacturing technology offers high potential to fabricate parts with complex geometries layer-by-layer. However, these parts have inhomogeneous microstructure and very poor surface quality in their as-built condition. The presence of high surface irregularities especially in the downskin surfaces is a...

Additive manufacturing is now leveraged to digitally fabricate complex and customized sand molds for castings. Mathematical equations can be employed in design to gracefully vary strut sizings volumetrically within lattices and the corresponding sand molds can be realized with binder jetting additive manufacturing. Consequently, geometrically tailo...

In laser powder bed fusion (L-PBF) of polymers, a proven material for biomedical applications is Polyamide12(PA 12) that is used for production of functional prototypes and end-use parts. The aim of this study is to investigate properties of insitu copper -modified polyamide (Sintratec PA12/B) at 10 wt.% Cu by L-PBF. Polymer-metal composites test s...

X-ray computed tomography is a common tool for non-destructive testing and analysis. One major application of this imaging technique is 3D porosity identification and quantification, which involves image segmentation of the analysed dataset. This segmentation step, which is most commonly performed using a global thresholding algorithm, has a major...

Metal powder bed fusion in additive manufacturing is gaining interest as a manufacturing technique for complex metal parts in the aerospace, rail, and automotive industries. This has led to an emergence of 3D printers in the market to accelerate the diffusion of this technology as an industrial manufacturing technique. The Aeroswift is an additive...

Additive manufacturing of ceramics is transforming electromagnetics by providing density-varying lattices and stochastic foams within arbitrary envelopes. Periodic structures can now be fabricated with zirconia which offers the highest permittivity of any 3D printable material possible to be printed with nearly-full-density. By arranging a lattice...

Quality concerns in laser powder bed fusion (L-PBF) include porosity, residual stresses and deformations during processing. Single tracks are the fundamental building blocks in L-PBF and their shape and geometry influence subsequent porosity in 3D L-PBF parts. The morphology of single tracks depends primarily on process parameters. The purpose of t...

The composition and evolution of kimberlitic magma has been proposed to form either as primary carbonatitic melts that during their ascent are contaminated by lithospheric silicate components, or by segregation of primary carbonated silicate melts in the kimberlite source. The highly dynamic and rapid magma transport and alteration of kimberlites d...

Additive manufacturing of ceramics stands to transform applications requiring wear resistance in severe environments (including high temperatures and pressures, harsh chemicals, and biomedical implants, among many other uses). However, applications in electromagnetics are gaining increased attention as newly-available materials like zirconia provid...

One of the major hurdles of laser powder bed fusion (L-PBF) is the inconsistent fatigue performance, depending on many possible defect types, microstructural differences, surface roughness effects, residual stresses and more, as described in other chapters in this book. Many improvements have been made in material properties by L-PBF process optimi...

Rationale: Our current understanding of tuberculosis pathophysiology is limited by a reliance on animal models, the paucity of human tuberculosis lung tissue, and traditional histopathological analysis, a destructive two-dimensional approach that provides limited spatial insight. Determining the three-dimensional (3D) structure of the necrotic gran...

Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (μCT) scanning (at 15 μm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide...

Laser powder bed fusion (LPBF) is a promising technology that requires further work to improve productivity to be adopted more widely. One possible approach is to increase the laser power and scan speed. A customized high-speed and high-power LPBF system has been developed for this purpose. The current study investigated the surface roughness and n...

Quantifying insect respiratory structures and their variation has remained challenging due to their microscopic size. Here we measure insect tracheal volume using X-ray micro-tomography (µCT) scanning (at 15 µm resolution) on living, sedated larvae of the cerambycid beetle Cacosceles newmannii across a range of body sizes. In this paper we provide...