Purpose Conventional manufacturing (CM) methods for complex forgings involve high energy consumption and substantial carbon emissions, posing significant environmental challenges. This study aims to evaluate the emissions of hybrid deposition and micro-rolling (HDMR) technology compared with CM in producing aviation forgings, assessing its feasibility as a sustainable alternative. Design/methodology/approach Using an industrial metabolism model based on carbon sources, this study conducts a carbon accounting analysis of the manufacturing process for an aircraft landing gear external cylinder. The carbon emission performance of HDMR and CM methods is evaluated and compared along two key dimensions: raw material consumption and energy usage. Findings The results show that the total CO2 output of the HDMR method for manufacturing the external cylinder are reduced by a coefficient of 32 compared to the CM method, and the metal raw material consumption is reduced by 85.40%. Originality/value This study proposes a novel industrial metabolism model to assess carbon emissions in HDMR processes. The results confirm the potential of HDMR to significantly reduce carbon footprint and material consumption in forging manufacturing, thereby supporting the transition of industry to low-carbon production.

Purpose In recent years, 3D printing technologies have grown significantly due to their versatility in producing components with complex geometries. In line with this trend, polylactic acid (PLA) has emerged as a highly applicable material due to its biocompatibility and biodegradability, along with adequate mechanical strength, making it suitable for the development of fastening and load-bearing components. However, the fabrication of such mechanical parts requires the consideration of multiple factors that ultimately influence both surface quality and mechanical properties of the final products. Design/methodology/approach In this study, a Design of Experiments (DOE) approach is implemented to vary the most critical parameters of the Fused Filament Fabrication (FFF) process, namely, nozzle diameter (ND), layer height (LH), extrusion temperature (TE), printing speed (PS) and extrusion multiplier (EM). Standardized specimens were used to measure the response variables. Adaptive Neuro-Fuzzy Inference System (ANFIS) models were developed to predict surface roughness, density and tensile strength, consistently outperforming regression models across all error metrics. A multi-objective optimization (MOO) based on particle swarm optimization was then applied to determine optimal processing conditions for PLA screw prototypes, which were subsequently manufactured (single- and double-thread) and validated through tensile and pull-out tests. Findings From the results, when all response variables had the same weight in the trade-off, the optimization indicated that the optimal parameter values within the selected range were ND = 0.25 mm, TE = 210 ºC, EM = 90%, LH = 0.1 mm and PS = 30 mm/s, achieving in the experimental validation a surface roughness (Ra) of 6.38 µm, a density of 1.2277 g/cm³ and an ultimate tensile strength of 63.20 MPa. Originality/value By combining ANFIS modeling with particle swarm-based MOO, this study provides a systematic strategy to identify optimal FFF processing parameters for PLA components. The integrated approach of modeling, optimization and experimental validation and experimental validation on PLA screw prototypes establishes a robust pathway for designing high-performance screws outperforming regression models. These findings underline the critical role of parameter tuning, where the optimization allows for trade-offs between mechanical performance and surface quality, which is very important in balancing strength, density and surface roughness, particularly in applications where multi-criteria optimization is essential.

Purpose The inherent strain method for laser powder bed fusion additive manufacturing (AM) allows for rapidly simulating process-induced distortion while still retaining the influence of thermomechanical physics. However, previous implementation of a single vector taken from a global average does not fully capture the known AM process results. This study aims to increase predicted accuracy in simulations by modifying the inherent strain method to better reflect experimentally defined print behavior. Design/methodology/approach This study analyzed the thermomechanical response of a small-scale AM part and applied the findings to a part-scale simulation, validated against experimental measurements of a benchmark geometry. This included the effects of the compressive core and the rapidly cooled tensile shell of an AM part and the differing in-plane and build-direction environments, captured with two strain vectors in the inherent strain method. Findings When compared to experimental X-ray diffraction strain measurements in the in-plane and build directions, simulation accuracy was improved from the traditional single-vector approach, reaching errors as low as 1% and lowering part median error from 82% to 17%. Originality/value This vector assignment approach better captures the process physics to improve AM simulation accuracy without sacrificing the lightweight computational cost advantage of inherent strain modeling. Part residual strain distribution was characterized, leading to a better understanding of post-print effects in AM parts.

Purpose Porous structures are crucial for wound dressings, but conventional 3D printing techniques often struggle to produce them effectively. This study aims to develop a one-step 3D printing method to fabricate polyurethane wound dressings with tunable pore architectures, addressing the limitations of traditional approaches. Surface roughness and porosity can be controlled in the present method, leading to a potential influence on cell behavior that promotes wound healing. Design/methodology/approach A novel immersion precipitation 3D printing (ip-3D printing) technique was used, leveraging solvent/non-solvent exchange to control porosity. Four solvent/non-solvent systems were tested to evaluate their effects on pore morphology, printability and biological performance. The resulting structures were characterized using scanning electron microscopy, mechanical testing, water uptake analysis and water vapor transmission rate (WVTR) measurements. In vitro biocompatibility was assessed via live/dead assays, MTS assays and cellular morphology analysis. Findings Non-solvent type and printing conditions significantly influenced pore structure, with exchange rate mechanisms (nucleation and growth, or spinodal decomposition) dictating pore morphology (dense, foam-like or fingerlike). WVTR measurements confirmed microstructure-dependent permeability. In vitro studies demonstrated excellent biocompatibility, with cellular behavior strongly linked to pore architecture. Originality This work introduces the application of one-step ip-3D printing method for foam-like polyurethane wound dressings for the first time, enabling precise control over pore size and surface morphology without post-processing. By linking solvent/non-solvent dynamics to cellular response, it offers a scalable platform for designing customized wound dressings with enhanced performance.

Purpose This study specifically focuses on low-to-medium infill densities where the influence of internal geometry on structural performance becomes most dominant. This study aims to explore how different infill patterns and densities affect the mechanical response of curved-axis beams produced by fused filament fabrication-based additive manufacturing (AM), providing insights for optimizing lightweight and material-efficient components subjected to bending loads. Design/methodology/approach Twenty-seven PLA-based specimens with varying curvature radii (500, 750 and 1000 mm), infill patterns (grid, triangular and trihexagonal) and densities (20%, 30% and 40%) were manufactured. Each was subjected to three-point bending tests following ASTM standards. The experimental approach focused on analyzing force-displacement behavior to evaluate stiffness, load capacity and deformation characteristics under static loading conditions. Findings Increasing infill density enhanced the maximum force capacity of curved beams but reduced their displacement tolerance, reflecting greater rigidity. The trihexagonal (TH) pattern exhibited the highest displacement values, confirming its energy absorption capability, while the triangular (TA) pattern provided the greatest rigidity with lower deformation. The grid (GR) pattern showed intermediate behavior, with displacement capacity strongly influenced by curvature radius. Straighter beams generally displayed reduced displacement and higher stability, while more curved beams exhibited greater deformation. These results highlight the critical role of infill geometry and curvature in balancing strength, stiffness and energy absorption in three-dimensional (3D)-printed curved beams. Originality/value Unlike prior studies that focus on high or near-solid infill levels, this work uniquely highlights the mechanical response of additively manufactured curved beams within the low-to-medium infill density range, where infill geometry plays a critical role. The study presents the first detailed comparison of how infill strategies interact with curvature in 3D-printed beams. It delivers practical design guidance for engineers working with curved structures in mechanical, aerospace and civil applications. Its novelty lies in demonstrating how trihexagonal patterns can optimize performance across various geometries, supporting enhanced structural resilience in AM.

Purpose The purpose of this study is to describe a technique for increasing the mechanical strength and toughness of three-dimensional (3D) printed thermoplastic parts by enclosing them within a conformal, dissolvable support shell. The mechanical property gains are achieved by subjecting the 3D printed parts to a post-print thermal annealing process at a temperature above the Tg of the core polymer. The shell mechanically supports the part during the annealing process so that the as-printed part geometry is maintained; after annealing, the support shell is dissolved to leave behind a high-strength, annealed thermoplastic part. Design/methodology/approach Parts are printed using acrylonitrile butadiene styrene (ABS) and shelled with polyvinyl alcohol (PVA) as part of the printing process. After printing, parts are annealed at a temperature (135°C) above the glass transition temperature (Tg) of ABS for 72 h, and then immersed in water to dissolve the support shell. Findings Coupon testing demonstrates more than 2× improvement in Izod impact strength compared to conventionally printed ABS. Additional demonstration parts subject to complex loading conditions show increases in failure load of 2–3× via the shell-annealing approach. These improved failure properties are due to wetting, reptation and entanglement processes that have been shown to occur under annealing conditions above Tg. Surprisingly, the PVA shell provides mechanical support during annealing, despite exhibiting an as-printed Tg below the annealing temperature. DMA and FTIR demonstrate that the PVATg increases during annealing due to crosslinking and crystallization. Practical implications This shell-annealing approach can be executed using off-the-shelf filaments and printers, making it easily accessible to the 3D printing community. Originality/value This study shares a new approach for printing and post-treating additively manufactured thermoplastic parts to achieve mechanical properties that are 2–3× higher than conventionally printed parts.

Purpose The purpose of this study is to investigate the production and performance of zinc borate–reinforced epoxy composites produced via additive manufacturing. This study aims to evaluate the effects of different zinc borate reinforcement ratios on the mechanical, thermal and fire retardancy properties of the composites. By analyzing the results, this study seeks to provide a deeper understanding of the potential of zinc borate as an eco-friendly flame retardant in advanced polymer composite applications. Design/methodology/approach Epoxy composites were reinforced with zinc borate at weight fractions of 0.5%, 1%, 2% and 3% using the stereolithography additive manufacturing method. The mechanical properties were characterized through tensile, three-point bending and dynamic mechanical analysis. Thermal properties were assessed using thermogravimetric analysis, and flame retardancy was evaluated with specific fire retardancy tests. Microstructural and chemical properties were examined via scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy analyses. In addition, hardness and thermal conductivity tests were performed to provide a comprehensive evaluation of the composites. Findings The incorporation of zinc borate significantly improved the thermal stability and mechanical properties of epoxy composites. Zinc borate acted as an effective flame retardant due to its hydrate groups, which enhanced thermal stability. However, the flame retardancy performance was found to be insufficient at lower reinforcement rates. This study highlights the potential of zinc borate as a multifunctional additive for enhancing the durability and performance of epoxy composites while emphasizing the need for further optimization to achieve superior flame retardancy. Originality/value This study represents an innovative approach by combining eco-friendly zinc borate reinforcement with advanced additive manufacturing techniques to produce high-performance polymer composites. It provides valuable insights into the interplay between reinforcement ratios and composite properties, offering a pathway for the optimization of zinc borate–reinforced materials. The findings contribute to the growing field of sustainable material development and establish a foundation for future studies in flame-retardant polymer composites.

Purpose This study aims to evaluate the effect of a wide range of printing speeds (50–500 mm/s) on the mechanical performance and production efficiency of polylactic acid (PLA) specimens produced by fused filament fabrication (FFF). It specifically addresses the underexplored behavior of PLA at high printing speeds exceeding 300 mm/s. Design/methodology/approach Using high-speed PLA filament, specimens were fabricated via FFF at a constant extrusion temperature of 230°C to isolate the influence of printing speed. Tensile testing was performed to assess mechanical properties, and manufacturing time was recorded. Normalized tensile strength and elastic modulus were calculated to reflect the balance between performance and production efficiency. Findings Increasing the printing speed from 50 to 150 mm/s improved tensile strength by 11.55% and elastic modulus by 8.4%, while reducing manufacturing time by over 60%. The elastic modulus reached a local maximum of 1332.55 MPa at 250 mm/s, with stable tensile strength in the 200–300 mm/s range. At 500 mm/s, the elastic modulus peaked at 1628.73 MPa, the highest among all tested speeds. Normalized metrics indicated significant gains in efficiency at lower speeds with only modest reductions in mechanical performance. Originality/value To the best of the authors’ knowledge, this study provides the first comprehensive investigation of PLA tensile behavior at FFF printing speeds up to 500 mm/s. The findings offer practical guidance for optimizing FFF process parameters to achieve a tradeoff between mechanical strength and rapid production, which is critical for industrial-scale high-speed 3D printing applications.

Purpose The purpose of this study is to develop a simple chemical method to remove support structure from hard-to-reach areas such as internal channels and cylindrical geometries of 3D printed Ti6Al4V alloy. Design/methodology/approach As compared to already published work, the ratios of hydrofluoric acid, nitric acid and deionized water have been used to remove the support structure without significantly affecting the part dimension. Replicas of internal channels in the form of titanium cylinders with 2 mm, 1.5 mm, 1.0 mm and 1.1 mm wall thickness with internal block supports were 3D printed by selective laser melting technology. Findings Among all tested ratios of HF: HNO3: H2O, 1:4:4 ratio (7.5 ml: 30 ml: 30 ml) was found to be the best optimized to attack only the weak support structure with minimal effect on the channel dimension. In all three selected samples, there is a constant reduction in cylinder thickness (approximately 0.1 mm) after support removal, which shows that for a constant support mass-to-volume of the chemical solution an initial margin to the channel size can be predicted to compensate for the loss of material. Originality/value The proposed method was also successfully implemented on a curved cylinder to demonstrate its usefulness for complex internal channels also.

Purpose The Laser Powder-Bed Fusion (L-PBF) process has shown growing potential in fabricating high-quality patterns for casting. This study aims to optimize L-PBF process parameters for Polystyrene (PS200) to enhance dimensional accuracy and Ultimate Compression Strength (UCS), ensuring pattern reliability during handling and molding. Design/methodology/approach A three-factor, three-level Box-Behnken Design under Response Surface Methodology was used to evaluate the effects and interactions of Laser Power, Laser Speed and Hatch Distance on UCS and dimensional deviation. Orientation-based mechanical and geometric evaluations were performed, followed by multi-objective optimization using the Non-Dominated Sorting Genetic Algorithm (NSGA-II). Findings Dimensional accuracy varied with orientation, with the Y-direction showing the lowest deviation (0.04–0.17 mm), while UCS was highest along the X-direction (1.16–3.85 MPa), indicating directional dependency. Optimization using NSGA-II provided a set of trade-off solutions, and the selected parameter set was used to fabricate a spherical PS200 pattern. The final aluminum cast part exhibited less than 1% dimensional deviation from the original pattern, validating the effectiveness of the optimized process. Research limitations/implications The findings are based on a specific machine–material combination. Broader generalization requires further research across different machines, geometries and material variants. Originality/value This study validates the use of PS200 in L-PBF for vacuum casting, achieving optimized, reliable patterns for high-precision small-batch production.