ABSTRACT In this paper, a novel facet clustering based method is proposed to generate alternative build orientations for laser powder bed fusion. This method consists of two steps. First, a hierarchical clustering algorithm is applied to divide facets of the design model in standard tessellation language format into different clusters, each of which shares a similar normal vector. Second, alternatives

The influence of the defocusing distance on melt pool morphology, defect, microstructure and mechanical properties of the laser powder bed fusion (L-PBF) of high strength Al–Cu–Mg–Mn alloy was studied. It is found that because of the different laser energy distribution, the defocusing distance has significant effects on melt pool morphology, defects, microstructure and mechanical properties of the

Bioprinting is a relatively new and promising tissue engineering approach to solve the problem of donor shortage for organ transplantation. It is a highly-advanced biofabrication system that enables the printing of materials in the form of biomaterials, living cells and growth factors in a layer-by-layer manner to manufacture 3D tissue-engineered constructs. The current workflow involves a myriad of

While significant progress has been made in laser powder bed fusion (L-PBF) for metal additive manufacturing (AM), there is still limited large scale adoption of this advanced manufacturing technique by the industry. This paper covers the recent developments in L-PBF with discussions from the materials and process perspectives. High entropy alloys and high strength aluminium alloys have been identified

Polymeric cellular structures based on triply periodic minimal surfaces (TPMS) have been widely studied for applications in multiple disciplines due to their multifunctionality. However, there is limited acoustic application by TPMS-based structures as their acoustic properties remain largely unknown. In this paper, TPMS-based structures are fabricated by additive manufacturing and investigated as

This paper examines the relationships in laser metal additive manufacturing between part geometry and as-built part quality, including residual stresses, deformations, process induced porosity, surface roughness, and microstructural variations. A comprehensive review of these defects and their relationships with the geometric features are provided along with a brief discussion of the involved physical

Blending Polyetheretherketone (PEEK) with Polyvinyl alcohol (PVA) is promising to obtain a composite scaffold combining the excellent biomechanical properties of PEEK and the remarkable degradability of PVA. However, the weak interfacial bonding between nonpolar PEEK and polar PVA would result in poor mechanical properties. In this study, owing to its unique amphiphilic properties, graphene oxide (GO)

ABSTRACT The rapid development of additive manufacturing of cementitious materials has enabled the emergence of a new design paradigm, namely functional grading of material properties by location. Target performance parameters could be material weight and insulation value or (particularly important) ductility. A generic concept to achieve this, is through the selective addition of fibres or aggregates

3D Concrete Printing (3DCP) has been gaining popularity in the past few years. Due to the nature of line-by-line printing and the slump of the material deposition in each extruded line, 3D printed structures exhibit obvious lines or marks at the layer interface, which affects surface finish quality and potentially affect bonding strength between layers. This makes it necessary to control the extrudate

ABSTRACT Lightweight and high-strength polymer-derived SiOC ceramics with varied lattice structures have been successfully produced using different polysiloxanes as preceramic polymers (PCPs) via photopolymerisation-based digital-light-processing 3D printing and pyrolysis. Photocurable precursor resins were prepared by simple mixing of polysiloxanes with photosensitive acrylate monomers, achieving

In recent years, additive manufacturing technology has been highly focused on its strong capability in complex geometry manufacturing and great suitability for customised product fabrication. Researchers have recognised the key role of additive manufacturing in leading the next-generation manufacturing, and have conducted extensive research from different aspects, including product design, process

ABSTRACT Additive manufacturing (AM) of co-fired low temperature ceramics offers a unique route for fabrication of novel 3D radio frequency (RF) and microwave communication components, embedded electronics and sensors. This paper describes the first-ever direct 3D printing of low temperature co-fired ceramics/floating electrode 3D structures. Slurry-based AM and selective laser burnout (SLB) were used

(2020). Editorial. Virtual and Physical Prototyping: Vol. 15, No. 2, pp. 131-132.

Metal-doped polymer derived ceramics (PDCs) exhibits multifunctional properties due to the introduction of special metal element; however as one of the cheapest metal element carriers, metal inorganic salts have rarely been reported for the fabrication of metal-doped PDCs. In this article, a novel hydrophilic photosensitive γ-methacryloxypropyl trimethoxy modified polyhydroxymethylsiloxane preceramic

Magnesium (Mg) alloy shows great potential as bone implant owing to its favourable biocompatibility and degradability. In the present work, bioglass-reinforced Mg-based composite was manufactured via laser additive manufacturing. The results showed that too low a volumetric energy density (Ev ) resulted in the appearance of open pores on the surface, which significantly deteriorated the densification

Metamaterials that exhibit negative Poisson’s ratio (NPR) are known as auxetics. They laterally expand or contract when they are axially tensioned or compressed. A re–entrant chiral auxetic structure (RCA) is a recently developed structure, which combines the topological features of re–entrant and chiral honeycombs. Comparative study between the RCA structure and popular benchmarks subjected to uniaxial

This paper aims to explore the effects of optimisation parameters (the filter radius, mesh size, and target volume fraction) on the compliance and manufacturability of smooth self-supporting topologies for additive manufacturing (AM); and conduct manufacturability experiments of selected simulation results with the Selective Laser Melting (SLM) technology. In this study, smooth self-supporting topologies

This paper presents a numerical study on stress-constrained shell-lattice infill structural optimisation. This problem is inherently challenging for several reasons: (i) different stress measures have to be used for the solid shell and the porous lattice infill, and the two types of stress constraints make the problem extremely complex to solve and (ii) involvement of the shell layer further complicates

Among the various Additive Manufacturing (AM) technologies available for metal part production, powder bed processes are the most promising for industrial mass production. However, one obstacle to the widespread adoption of AM technologies is the effect of the residual stress state on the integrity and lifetime of parts. The residual stress state is influenced to a great extent by the geometry and

A solution-based electrohydrodynamic (EHD) printing strategy was developed to fabricate sub-microscale biopolymeric fibres to mimic the tiny architectures of native extracellular matrix (ECM) for enhanced cellular performance. It was found that when the working voltage was significantly reduced to 500 V, sub-microscale fibres as well as user-specific patterns with an average fibre size of 193 ± 51 nm

This work presents a comprehensive failure mechanism study of the bi-directionally corrugated panel (DCP) structures inspired by the telson of mantis shrimp. The DCP structures were fabricated by selective laser melting (SLM) with AlSi10Mg powder. The influence of key structural parameters, namely wave number (N), on the compressive behaviours, stress distribution, deformation modes and fracture mechanism

The microstructure of metals depends on the additive manufacturing (AM) process and the process parameters. However, experimentation on different process parameters for different materials is costly and time-consuming. To overcome these challenges, numerical simulations provide insights that allow prediction of microstructure formed under different process parameters. Microstructure modelling requires

Multi-objective optimisation of the bio-inspired lightweight structure is developed by response surface methodology (RSM) and non-dominated sorting genetic algorithm II (NSGA-II) for future applications in the aerospace and military fields. Multilayer bio-inspired sandwich structures of Ti6Al4V alloy are designed and fabricated by selective laser melting (SLM). Results show that the bio-inspired sandwich

Three-dimensional (3D) printed Sc-modified Al alloy by powder bed fusion (PBF) provides significant strength and ductility without hot tearing during the process. This kind of 3D-printable high specific strength materials exhibits great potential in lightweight applications. Due to the lesser design limitation through the 3D printing process, the degree of lightweight is greatly affected by the specific

Flexible electronics are attractive because of flexibility and portability. The circuits are printed on flexible substrates, which are delicate and heat-sensitive. Traditional photolithography, which uses high temperatures and corrosive chemicals, easily causes damages in flexible substrates. Here, we develop a low-cost nanoparticle based laser patterning process for fabrication of flexible electronics

To evaluate specimen size dependence on the tensile properties of additively manufactured (AM) components, various rectangular specimens, ranging from miniaturised to ASTM standard specimens, are machined from electron beam melted Ti-6Al-4V and used for the tensile testing. It is found that the elongation is strongly related to the sample size while the yield and ultimate tensile strengths exhibit

Highly accurate rendering of the external and internal geometry of bone tissue engineering scaffolds effects fit at the defect site, loading of internal pore spaces with cells, bioreactor-delivered nutrient and growth factor circulation, and scaffold resorption. It may be necessary to render resorbable polymer scaffolds with 50 μm or less accuracy to achieve these goals. This level of accuracy is available