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Polymer laser powder bed fusion (PBF-LB/P) is an additive manufacturing technology that is sustainable due to the possibility of recycling the powder multiple times and allowing the fabrication of gears without the aid of support structures and subsequent assembly. However, there are constraints in the process that negatively affect its adoption compared to other additive technologies such as material extrusion to produce gears. This study aims to demonstrate that it is possible to overcome the problems due to the physics of the process to produce accurate mechanism.

Technological aspects such as orientation, wheel-shaft thicknesses and degree of powder recycling were examined. Furthermore, the evolving tooth profile was considered as a design parameter to provide a manufacturability map of gear-based mechanisms.

Results show that there are some differences in the functioning of the gear depending on the type of powder used, 100% virgin or 50% virgin and 50% recycled for five cycles. The application of a groove on a gear produced with 100% virgin powder allows the mechanism to be easily unlocked regardless of the orientation and wheel-shaft thicknesses. The application of a specific evolutionary profile independent of the diameter of the reference circle on vertically oriented gears guarantees rotation continuity while preserving the functionality of the assembled mechanism.

In the literature, there are various studies on material aging and reuse in the PBF-LB/P process, mainly focused on the powder deterioration mechanism, powder fluidity, microstructure and mechanical properties of the parts and process parameters. This study, instead, was focused on the functioning of gears, which represent one of the applications in which this technology can have great success, by analyzing the two main effects that can compromise it: recycled powder and vertical orientation during construction.

This study aims to enhance merging of additive manufacturing (AM) techniques with powder injection molding (PIM). In this way, the prototypes could be 3D-printed and mass production implemented using PIM. Thus, the surface properties and mechanical performance of parts produced using powder/polymer binder feedstocks [material extrusion (MEX) and PIM] were investigated and compared with powder manufacturing based on direct metal laser sintering (DMLS).

PIM parts were manufactured from 17-4PH stainless steel PIM-quality powder and powder intended for powder bed fusion compounded with a recently developed environmentally benign binder. Rheological data obtained at the relevant temperatures were used to set up the process parameters of injection molding. The tensile and yield strengths as well as the strain at break were determined for PIM sintered parts and compared to those produced using MEX and DMLS. Surface properties were evaluated through a 3D scanner and analyzed with advanced statistical tools.

Advanced statistical analyses of the surface properties showed the proximity between the surfaces created via PIM and MEX. The tensile and yield strengths, as well as the strain at break, suggested that DMLS provides sintered samples with the highest strength and ductility; however, PIM parts made from environmentally benign feedstock may successfully compete with this manufacturing route.

This study addresses the issues connected to the merging of two environmentally efficient processing routes. The literature survey included has shown that there is so far no study comparing AM and PIM techniques systematically on the fixed part shape and dimensions using advanced statistical tools to derive the proximity of the investigated processing routes.

Although ceramic additive manufacturing (AM) could be used to fabricate complex, high-resolution parts for diverse, functional applications, one ongoing challenge is optimizing the post-process, particularly sintering, conditions to consistently produce geometrically accurate and mechanically robust parts. This study aims to investigate how sintering temperature affects feature resolution and flexural properties of silica-based parts formed by vat photopolymerization (VPP) AM.

Test artifacts were designed to evaluate features of different sizes, shapes and orientations, and three-point bend specimens printed in multiple orientations were used to evaluate mechanical properties. Sintering temperatures were varied between 1000°C and 1300°C.

Deviations from designed dimensions often increased with higher sintering temperatures and/or larger features. Higher sintering temperatures yielded parts with higher strength and lower strain at break. Many features exhibited defects, often dependent on geometry and sintering temperature, highlighting the need for further analysis of debinding and sintering parameters.

To the best of the authors’ knowledge, this is the first time test artifacts have been designed for ceramic VPP. This work also offers insights into the effect of sintering temperature and print orientation on flexural properties. These results provide design guidelines for a particular material, while the methodology outlined for assessing feature resolution and flexural strength is broadly applicable to other ceramics, enabling more predictable part performance when considering the future design and manufacture of complex ceramic parts.

The ability to use laser powder bed fusion (LPBF) to print parts with tailored surface topography could reduce the need for costly post-processing. However, characterizing the as-built surface topography as a function of process parameters is crucial to establishing linkages between process parameters and surface topography and is currently not well understood. The purpose of this study is to measure the effect of different LPBF process parameters on the as-built surface topography of Inconel 718 parts.

Inconel 718 truncheon specimens with different process parameters, including single- and double contour laser pass, laser power, laser scan speed, build orientation and characterize their as-built surface topography using deterministic and areal surface topography parameters are printed. The effect of both individual process parameters, as well as their interactions, on the as-built surface topography are evaluated and linked to the underlying physics, informed by surface topography data.

Deterministic surface topography parameters are more suitable than areal surface topography parameters to characterize the distinct features of the as-built surfaces that result from LPBF. The as-built surface topography is strongly dependent on the built orientation and is dominated by the staircase effect for shallow orientations and partially fused metal powder particles for steep orientations. Laser power and laser scan speed have a combined effect on the as-built surface topography, even when maintaining constant laser energy density.

This work addresses two knowledge gaps. (i) It introduces deterministic instead of areal surface topography parameters to unambiguously characterize the as-built LPBF surfaces. (ii) It provides a methodical study of the as-built surface topography as a function of individual LPBF process parameters and their interaction effects.

The purpose of this paper is to verify the performance and function of the scale-up prototypes by predicting the material and energy consumption on the basis of dimension-reduced prototypes. Additive manufacturing (AM) costs determine carbon emissions in total life cycle, among which material and energy consumption are major components. Predicting material and energy consumption is fundamental to reducing costs.

This paper presents a material and energy co-optimization method for AM via multiple layers prediction (MLP). Material and energy consumption are predicted to reduce the AM costs. In particular, scalable, complex curved surface component is used to improve forecasting efficiency. Subsequently, the back pressure distribution is obtained by scale-up specimens, which can lay the foundation for the ergonomic conceptual design.

Taking evolutionary ergonomic product as an example, the relative gravity direction of backrest is calculated. The material and energy consumption are predicted with low deviation. Physical experiments were carried out to validate information. Digital and physical tests have revealed that material and energy co-optimization improves manufacturing efficiency.

The innovatively proposed MLP method predicts material and energy consumption of scale-up prototypes to reduce the costs. It is propitious to improve the carbon emission efficiency in life cycle of AM. The originality may be widely adopted alongside increasing environmental awareness.

The 3DCastleBenchy has been developed to facilitate wider adoption and use of additive manufacturing benchmarking artefacts which encourage both technical and non-technical users and designers to connect the growing number of technologies available. This tool will help people working with additive manufacturing to gain understanding of the limitations and design rules for each process.

Benchmarking is of critical importance for additive manufacturing, allowing for comparisons between technology capability, process optimisation and design guidelines. This work presents the 3DCastleBenchy, a design which balances aesthetic appeal and specific, measurable features which can be used for comparing various additive manufacturing processes.

The benchmark design was fabricated with three fundamentally different metal additive processes, laser-directed energy deposition (L-DED), laser powder bed fusion (L-PBF) and metal extrusion (MEX). These resulting parts were then analysed, thereby allowing common defects and limitations of each process to be identified, namely, the overhang limitations of traditional L-DED, the cracking that can occur in L-PBF and the deposition tool path artefacts present in MEX.

Existing benchmarks typically focus on either tolerance engineering features, or they are purely artistic/demonstrative pieces. The 3DCastleBenchy has been designed to find a balance between these objectives to facilitate communication of design for additive manufacturing concepts.

Owing to its leverage of high deposition rate, the wire arc additive manufacturing (WAAM) process is being adopted for the development of IN718 alloy used in aerospace, transportation and energy sectors. The purpose of this study is to observe the effect of process parameters on the mechanical properties of the IN718 superalloy.

This study emphasizes the effect of WAAM process parameters on mechanical and metallurgical properties of developed multilayer structures of IN718 alloy by means of orthogonally designed experiments.

The results show that high current and voltage settings, combined with low welding speed, provide increase bead width, height and effective wall area, while resulting in decrease surface waviness, hardness and tensile properties. The scanning electron microscopy and energy dispersive spectroscopy results show the presence of secondary precipitates such as NbC and Ni3(Al, Ti) in low-heat samples, which improve the mechanical properties of the material. However, the presence of Laves phases deteriorates the mechanical properties in high-heat samples. The electron backscatter diffraction results confirmed the presence of more grain boundaries and highly textured surfaces in lower heat samples, which improves mechanical properties.

The effect of process parameters on the microstructural features and mechanical properties along with bead characteristic are studied in-depth and influence of each parameter are discussed.

This study aims to better understand the influence of various post-treatments on the microstructure and mechanical properties of additively manufactured parts for critical applications.

In this study, Laser Powder Bed Fusion (LPBF) fabricated Inconel 718 (IN718) samples were subjected to various heat treatments, namely homogenization, solution heat treatment and double aging, to investigate their influence on the microstructure, mechanical properties and fracture mechanism at an elevated temperature of 650 °C. Homogenization treatment was performed at 1080 °C for durations ranging from 1–8 h. The solution treatment temperature varied from 980 °C to 1140 °C for 1 h, followed by double aging treatment.

At 650 °C, the as-built sample showed the minimum strength but demonstrated the maximum elongation to failure compared to the heat-treated samples. The strength of the IN718 superalloy increased by 20.26% to 34.81%, while ductility significantly reduced by 65.26% to 72.89% after various heat treatments compared to the as-built state. This change is attributed to the enhancement in grain boundary strength resulting from the pinning effect of the intergranular δ-phase.

The study observed that the variations in the fracture mechanism of LPBF fabricated IN718 depend on the duration and temperature of heat treatment. This research provides a thorough overview of the high-temperature mechanical properties of LPBF fabricated IN718 subjected to different homogenization times and solution treatment temperatures, correlating these effects to the corresponding changes in microstructure.

The purpose of this study is to develop a low-cost and efficient method for 3D printing CuSn15 bronze alloy parts using a pneumatic extrusion system. By avoiding complex processes such as filament preparation and solvent/catalytic debinding, the study aims to streamline the low-cost production process of metallic components while maintaining high mechanical performance. The research also seeks to evaluate the effects of different sintering temperatures and times on the mechanical properties of the printed parts.

A simple and cost-effective pneumatic extrusion system was designed to 3D print a metal paste containing CuSn15 alloy powders. The metal paste was prepared by manually mixing of CuSn15 powders, carboxymethyl cellulose and distilled water. The printed parts were subsequently dried and sintered at various temperatures and times to study the effects of these parameters on the material properties. Tensile test and scanning electron microscope analysis were conducted to assess the structural integrity and mechanical performance of the samples.

The study found that the pneumatic extrusion system enabled the successful 3D printing of CuSn15 bronze alloy parts without the need for complex processes. Increasing sintering temperature led to improved mechanical properties and decreased porosity. Increasing the sintering time at 820 °C led to a reduction in mechanical performance. The study demonstrated that the sintering parameters significantly influence the porosity and mechanical properties of the printed parts.

This study introduces a novel approach to 3D printing CuSn15 bronze alloy using a pneumatic extrusion system, eliminating the need for traditional filament preparation and solvent/catalytic debinding processes. The research provides new insights into the effect of sintering parameters on the mechanical properties of additively manufactured metal parts. By simplifying the production process, this study offers a low-cost, efficient method for producing complex-shaped metallic components, potentially expanding the applicability of 3D printing in industries such as electronics, marine and mechanical engineering.