Additive Manufacturing (AM) and printing-based fabrication technologies have emerged as powerful enablers for next-generation electronic integration and packaging, addressing the growing limitations of conventional subtractive manufacturing techniques. As electronic systems continue to scale toward higher operating frequencies (10–110 GHz and beyond) and increased functional density (>104 interconnects/cm2), traditional packaging approaches struggle with rigid design constraints, complex processing steps (>15–25 fabrication steps), high tooling costs ($10,000–$100,000 for mask and molds) and limited compatibility with heterogeneous integration. In this review, a comprehensive and critical overview of major additive manufacturing and printing technologies including aerosol jet printing, inkjet printing, vat polymerization, fused filament fabrication (FFF) and nScrypt printing is presented from the perspective of electronic assembly and packaging. The fundamental working mechanisms, material compatibility, resolution limits, scalability, and reliability considerations of each technique are systematically discussed. From a manufacturing standpoint, AM reduces material waste by 50–90% compared to subtractive PCB processing and eliminates tooling costs, enabling low-volume prototyping with per-unit fabrication costs reduced by 30–70% for small batches (<100 units). Production throughput varies widely, from 1 to 20 cm2/min for high-resolution direct write systems to >100 cm2/min for scalable inkjet systems. Moreover, it is discussed how these technologies enable advanced packaging architectures such as printed signal crossovers, three-dimensional interconnects, ramps, and embedded chip assemblies. Recent research efforts and reported demonstrations are analyzed to highlight the advantages and current limitations of additive manufacturing for high-frequency, RF, and system-on-package (SoP) applications. Finally, future directions and remaining challenges are discussed, including advances in materials, custom and on-demand manufacturing, enhanced design freedom, integration of multifunctionality, cost-effectiveness, and smart packaging solutions. This review aims to serve as a reference for researchers and engineers seeking to leverage additive manufacturing for high-performance electronic integration and next-generation electronic packaging solutions.

This study explores the passive separation of solid particles from liquid suspensions in spiral separators fabricated using fused filament fabrication (FFF) and stereolithography (SLA). Building on prior work, we investigate the effect of microchannel geometry, circular vs. square cross-sections of equal area, and printing method on separation performance. Devices were tested across a wider range of flow rates (150 mL min−1–350 mL min−1), extending into transitional regimes, to examine geometry-induced inertial effects. Separation performance was quantified using the normalized outlet mass difference (Δ) for talc, precipitated calcium carbonate, and quartz. Maximum separation was obtained for quartz sand in the SLA separator at 250 mL min−1 (Δ = 0.2175 g per 100 mL), while talc showed the highest mass difference in the square FFF separator at 300 mL min−1 (Δ = 0.1196 g per 100 mL). For calcium carbonate, the highest separation occurred in the SLA device at 250 mL min−1 (Δ = 0.1721 g per 100 mL), though performance was limited by agglomeration and clogging in FFF devices. Overall, separation was predominantly mass-based rather than strictly size-selective, with channel geometry, flow regime, and fabrication method jointly governing performance.

The teaching of instrumentation has consistently been a fundamental component of undergraduate programs in radiological technology (RT). However, opportunities for students to engage in direct, hands-on operation of linear accelerator (LINAC) machines during their education and training are often constrained by financial limitations and time restrictions. Therefore, this study aims to integrate a 3D-printed model into LINAC machine topic and evaluate its effectiveness in teaching RT undergraduate students. To achieve this, a physical LINAC model was developed using fused deposition modeling 3D printing technology, with access facilitated through open-source software. To enhance comprehension, color coding was incorporated along with explanatory color cards. A total of 114 participants were randomly assigned to either a control group or a 3D model group. Comparative analysis of theoretical assessment scores revealed that the 3D model group performed significantly better than the control group, with a p-value of < 0.05. Furthermore, the increased opportunity for hands-on training prior to apprenticeships resulted in reduced anxiety and improved clinical performance among participants in the 3D model group. To assess student perceptions regarding the integration of this novel 3D technology into LINAC teaching, participant feedback was collected. Results indicated that over 94% of students recognized the alternative teaching method as essential for enhancing both their theoretical understanding and practical skills. In conclusion, the incorporation of modern 3D-printed models into RT education demonstrates considerable potential for enriching teaching and training activities, ultimately contributing to improved educational outcomes in radiological technology programs.

New perspectives on intra-layer reheating in fused filament fabrication

Numerical analysis on the effect of the orifice embedded nozzle and the squeeze flow on fiber alignment in the fused filament fabrication

Influence of fused filament fabrication process parameters on the quasi-static mechanical behaviour and failure mechanisms of 316L stainless steel

Dropwise condensation on fused deposition modeling fabricated copper-infused heat-treatable polylactic acid substrates

The global polymer waste burden has catalyzed a shift from linear “production–use–disposal” systems to circular models that prioritize recycling, reuse, and value retention. This article proposes an integrated, technology-ready roadmap for mechanical recycling and reuse of commodity and bio-based polymers via filament re-extrusion and Additive Manufacturing (AM). Building upon recent findings on performance envelopes of virgin vs. recycled Polylactic Acid (PLA) filaments processed by Fused Deposition Modeling (FDM), process parameter sensitivities (layer height, infill density) and their statistical optimization, and functional reinforcement routes (aluminum: Al, alumina: Al2O3, titanium: Ti, and Nano Boron Nitride: nano-BN), we articulate (1) a process–structure–property (PSP) mapping; (2) a low-defect, low-energy filament re-extrusion protocol; and (3) a graded-value strategy for upcycling mixed polymer streams. Across case analyses, we show that recycled PLA can achieve near-parity with virgin PLA when extrusion quality and printing parameters are controlled, and that ceramic/metal nanofillers enable thermal management and biocompatibility benefits crucial for durable reuse scenarios.

Fused Filament Fabrication (FFF) is a low-cost additive manufacturing process that produces metallic parts from printing with a metal-polymer filament, followed by a debinding–sintering process. It presents an opportunity for the tooling sector to improve performance by geometrical optimization while keeping costs low. This study investigates the possibility of producing a molding core for plastic injection by FFF technology. This research aimed to characterize 17-4 PH stainless steel and H13 hot work tool steels produced through this process. Their heat treatment behavior was investigated using dilatometry, which led to the obtention of a Continuous Cooling Transformation (CCT) diagram. Results show that for as-sintered materials, martensitic steel with some residual austenite is present in 17-4 PH, and a pearlitic microstructure is observed in H13. Porosity (around 4%) falls within the reported range in the literature and can be removed by hot isostatic pressing. CCT diagrams do not show significant differences with conventional materials. The low hardness of as-sintered H13 (around 175 HV1) is improved (>500 HV1) by suitable heat treatment. Finally, both materials meet the requirements for this specific industrial application, and demonstrators were produced.

Heat creep is a critical failure mechanism in fused filament fabrication (FFF) extrusion systems, arising from insufficient thermal isolation between the hot end and cold end. It causes premature polymer softening, extrusion instability, and nozzle clogging, especially when active cooling is reduced or lost. This study experimentally evaluates passive cooling strategies for mitigating heat creep in consumer-class printers by exploiting ambient thermal stratification within the build volume. Vertical air-temperature gradients above heated build plates were measured for enclosed, semi-enclosed, and open-frame architectures, revealing pronounced stratification. Cold-end temperatures were then quantified for a stock extruder under forced and natural convection while printing polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). Finally, a modified cold-end using a heat pipe to relocate heat rejection to an elevated heat sink was tested under identical conditions, assuming fan failure. Elevated heat-rejection locations experienced lower ambient temperatures and improved natural-convection heat transfer. Relative to the stock configuration, the augmented design reduced cold-end temperatures and improved thermal stability during representative printing cycles without continuous active cooling—the improvement percent is ~8%. The results demonstrate that coupling heat-pipe conduction with environmental thermal gradients can mitigate heat creep and improve extruder reliability with lower energy demand.

Advances in additive manufacturing have greatly expanded the design possibilities for novel biomimetic honeycomb structures. Inspired by the hierarchical architecture of spider webs and the sinusoidal micro‐geometry of the woodpecker’s beak, this study proposes a biomimetic sinusoidal mesh honeycomb (BSMH) structure, characterized by sinusoidal‐shaped cell walls coupled into a web‐like honeycomb topology. This unique configuration allows tunable mechanical and energy absorption properties. Specimens were fabricated using fused filament fabrication (FFF) and subjected to quasi‐static out‐of‐plane compression tests. Combining experiments, theoretical analysis, and finite element simulations, this study systematically investigates the axial compression behavior, collapse mechanisms and energy absorption performance of the BSMH, with a primary focus on its mechanical performance and energy absorption capacity under quasi-static loading. A parametric study examined the influence of sinusoidal amplitude ( A = 0.3–0.9 mm), wave number ( n = 1–3), and relative cell count ( q = 5, 7, 9)—on energy absorption performance. Key performance metrics-total energy absorption (EA), specific energy absorption (SEA), mean crushing force (MCF), and peak crushing force (PCF) were analyzed to identify performance trends. Results demonstrate that by adjusting these geometric parameters, the deformation modes and stress distribution can be effectively controlled, leading to significant enhancements in energy absorption efficiency. The BSMH design offers a novel approach to developing lightweight, high-performance sandwich cores, showing strong potential for practical applications—including energy-absorbing wall panels, protective liners, and lightweight yet strong components where efficient crashworthiness and a tunable load-response are essential.

This study aimed to optimize the fused deposition modeling (FDM) process parameters for an 8% aramid fiber-reinforced polyamide filament (NylonAF80) to enhance the quality of printed parts. Six parameters were varied: the slice height, nozzle temperature, bed temperature, deposition speed, raster orientation, and build orientation. Cuboid samples with a central circular hole were printed using Taguchi's L18 orthogonal array, and evaluated for volumetric error, average roughness, and Shore D hardness. The CRITIC-CoCoSo technique identified optimal settings of 0.1mm slice height, 255°C nozzle temperature, 100°C bed temperature, 40mm/s deposition speed, 90° raster orientation, and on-edge build orientation to maximize the multi-response performance index. Sensitivity analysis using different weighting schemes and MCDM methods showed strong correlations (> 0.93) between rankings. The decision tree algorithm exhibited superior performance to k-nearest neighbor, stochastic gradient descent, and logistic regression in classifying output responses, achieving 88.9%, 94.4%, and 100% accuracies for hardness, volumetric error, and roughness, respectively, at an 80:20 split ratio. Slice height was the most influential factor for all responses. FESEM microstructural analysis revealed pores and voids in the samples printed under extreme conditions and at high slice heights. These findings provide valuable insights for optimizing FDM parameters to improve the quality of NylonAF80 parts for industrial applications.

This paper investigates the process that forms an adhesive bond between the polylactic acid (PLA) polymer and textile substrates during direct Fused Deposition Modeling (FDM) printing, which is used to make printed products with integrated 3D elements. The task addressed relates to the insufficient understanding of the influence exerted by the structural characteristics of textile materials and additive printing parameters on the quality and stability of the adhesive layer. This study has established patterns of interaction between PLA and fabrics of different densities, thicknesses, and surface topographies. Mechanical pull-off tests were conducted to quantitatively assess the adhesive strength and determine the relationship between the pull-off force and the technological parameters of printing. It is shown that increased extrusion temperatures, average extruder travel speed, and minimum Z-distance between the nozzle and the base enable the formation of a more stable bond. The effect of preliminary application of an adhesive layer was investigated, which in certain cases further increases the adhesive interaction. The results have made it possible to solve the task by comprehensively taking into account the structural features of textile bases and the physical and technological factors of FDM printing. The identified patterns are explained by a combination of thermomechanical effects during PLA extrusion and the ability of textile fibers to provide micromechanical fixation of the polymer. The findings could be effectively used in the context of the introduction of additive technologies in printing.

Primary flight feather shafts, a critical structural component of avian flight, exhibit excellent mechanical properties. The cross-sectional and medullary foam internal cavity structures of the feather shaft exhibit a gradual variation along the shaft; however, the mechanism by which this gradual variation influences the mechanical properties of the shaft remains unclear. In this study, the structural characteristics of a primary flight feather shaft were analyzed. Subsequently, the effects of gradual variations in the cross-sectional shape and medullary foam internal cavity structure along the shaft on its buckling resistance, torsional stiffness, and bending behavior were investigated. The experimental results showed that, along the length of the primary flight feather shaft, its cross-sectional shape transitions progressively from circular to approximately pentagonal and finally to quadrilateral, while its medullary foam cavity structure gradually changes from a circular to an inverted triangular shape. Feather shafts with an approximately pentagonal cross-section and an elliptical medullary foam cavity structure exhibit excellent buckling resistance, torsional resistance, and bending stability. Finally, based on the structural characteristics of the feather shaft, bionic samples with different cross-sectional shapes and medullary foam cavity structures were fabricated using fused deposition modeling (FDM), and their bending properties were assessed through three-point bending tests. The experimental results demonstrated that the bioinspired prototype, featuring an approximately pentagonal cross-section and an elliptical medullary foam cavity structure exhibited optimal bending properties, achieving a maximum specific load-bearing capacity of 102.64±1.66 N/g. This study provides bio-inspired insights into the design of lightweight structures.

This study investigates the flexural performance of polylactic acid (PLA) reinforced with eggshell-derived calcium carbonate (CaCO 3 ) at 5, 10, 15, and 20 wt.% for sustainable fused filament fabrication applications. Composite filaments were fabricated via extrusion, and test specimens were manufactured using fused filament fabrication (FFF). Standard three-point bending tests revealed that a 15 wt.% CaCO 3 composite achieved the highest flexural strength (76 MPa) and modulus (1404 MPa), indicating optimal filler–matrix interaction and efficient stress transfer. A 5 wt.% CaCO 3 addition significantly enhanced ductility, yielding a maximum strain to failure of 7.03%. Further increase to 20 wt.% resulted in mechanical degradation due to particle agglomeration and reduced matrix continuity. These findings demonstrate that eggshell-derived CaCO 3 is an effective sustainable reinforcement for tailoring stiffness and strength in PLA-based components intended for lightweight structural and eco-friendly engineering applications.

Experimental and Simulation Analysis of Fused Deposition Modeling 3D-Printed Polylactic Acid Joints Developed Using Susceptor-Free Microwave Heating Approach

Background: Reconstruction of the proximal humerus after wide tumor resection is technically demanding, and traditional methods such as allograft-prosthetic composites, reverse shoulder arthroplasty, and metal implants are limited by graft unavailability, pediatric size mismatch, their high cost, and metal-related stress shielding. Polyether ether ketone (PEEK), with its modulus closer to cortical bone and radiolucency, offers a promising alternative. Building upon the success in craniomaxillofacial surgery and its favorable physical characteristics, we applied personalized 3D-printed PEEK implants for proximal humerus reconstruction. This study reports the first evidence of applying patient-specific 3D-printed PEEK implants in the proximal humerus. Methods: A retrospective cohort study was conducted on seven patients who underwent wide resection of primary malignant bone tumors of the proximal humerus, followed by reconstruction using patient-specific 3D-printed PEEK implants. Implant design was based on preoperative computed tomography (CT) imaging, incorporating contralateral humeral mirroring and computer-aided design. The implants were fabricated using fused deposition modeling (FDM) with medical-grade PEEK under stringent thermal control (nozzle temperature > 400 °C and heated build chamber), followed by a controlled annealing process to minimize internal stress, optimize polymer crystallinity, and enhance mechanical durability. Outcomes assessed included implant survival, oncologic control, shoulder range of motion, and functional outcomes measured using the Musculoskeletal Tumor Society (MSTS) score. The mean follow-up duration was 56.3 months. Results: All patient-specific PEEK implants were successfully manufactured and implanted with satisfactory geometric accuracy. Mechanical implant survival was 85.7% at final follow-up, with one implant fracture occurring at 28 months. No cases of deep infection, dislocation, loosening, or permanent neurovascular injury were observed. Local soft-tissue recurrence occurred in two patients (28.6%), without distant metastasis or tumor-related mortality. The limb-salvage rate was 100%. At final follow-up, the mean MSTS score was 23.0 ± 1.6. Shoulder motion was limited but comparable to outcomes reported for conventional anatomic megaprosthetic reconstructions. Conclusions: Patient-specific 3D-printed PEEK implants provide a feasible and oncologically safe option for proximal humerus reconstruction after tumor resection, with acceptable midterm implant survival and functional outcomes. The favorable elastic modulus and radiolucency of PEEK offer distinct biomechanical and imaging advantages over metallic implants. Further design optimization and larger prospective studies are warranted to enhance mechanical durability and functional restoration.

This is the description of Option 2. Purpose In additive manufacturing of fiber-reinforced composites, fused deposition modeling (FDM) has been widely adopted due to its low complexity and high flexibility. However, the formation of void defects during the process severely limits the mechanical performance of printed components. This study aims to systematically investigate the influence of void orientation, size, and distribution on the mechanical properties of 3D-printed carbon fiber/PA6 composites, and to explore an epoxy resin repair strategy for performance enhancement. Design/methodology/approach In this study, short carbon fiber/polyamide 6 (SCF/PA6) and continuous carbon fiber/polyamide 6 (CCF/PA6) composites were used, and different types of void defects were designed to investigate the influence of void orientation, size and distribution patterns on mechanical properties. Findings The results demonstrate that when void defects are oriented differently, composites containing voids in the Z-direction exhibit the lowest strength, reaching 83.6 MPa. Regarding defect size and distribution, the failure of fiber-reinforced composites is governed by stress–strain interactions, where both competitive and synergistic mechanisms coexist. Originality/value Furthermore, this work proposes an epoxy resin repair strategy, which enhances the mechanical performance of composites through combined physical and chemical interactions.

This paper investigates the feasibility of manufacturing hydraulic fittings using additive manufacturing (AM) technologies, specifically Fused Deposition Modeling (FDM) and Stereolithography (SLA). The study addresses the environmental challenge of material waste in conventional fitting production by exploring 3D printing as an alternative manufacturing method. Hydraulic fittings were designed using CAD software: SolidWorks 2022 and fabricated using FDM with PETG (Polyethene Terephthalate Glycol) material and SLA with UV-sensitive photopolymer resin. In present studies, on-destructive leak testing was conducted in accordance with PN-EN 1254-4 and PN-EN 1254, at pressures ranging from 0.1 to 1.0 bar. Dimensional accuracy analysis revealed shrinkage of approximately 1% for SLA-printed parts and 2% for FDM-printed parts. Microscopic examination at 50× and 80× magnification showed superior thread quality in SLA samples compared to FDM, which exhibited visible layer separation and material porosity. Leak testing demonstrated that while the brass reference fitting maintained complete seal integrity, both 3D-printed variants failed to achieve leak tightness under operational pressures, with structural failure occurring at 1.0 bar during tightening. The study showed that FDM with PETG material and SLA with UV-sensitive photopolymer resin, despite achieving acceptable dimensional tolerances (±1-2%), do not meet hydraulic leak tightness requirements at pressures exceeding 0.5 bar in their raw state after printing. The results suggest that alternative material formulations (e.g., carbon fiber-reinforced PEEK for FDM or epoxy engineering resins for SLA) warrant further investigation. Potential avenues for improvement include advanced surface treatment, optimization of printing parameters, and modifications to thread geometry to reduce interthread gaps.

With the rapid development of sustainable materials and additive manufacturing technologies, glass fiber-reinforced recycled polypropylene (GF/RPP) has shown enormous potential for application in fused deposition modeling (FDM). However, the mechanical performance of GF/RPP parts is significantly affected by the FDM process parameters, and multi-objective parameter optimization remains a critical challenge. To address this, a novel multi-attribute decision-making (MADM) framework based on the interval-valued T-spherical fuzzy weighted power Heronian mean operator and Combined Compromise Solution (IVTSFWPHM-CoCoSo) is proposed to optimize FDM process parameters. The framework employs the IVTSFWPHM operator to handle experimental uncertainty, capture interactions among multiple mechanical properties, and reduce the influence of extreme values. The improved entropy weight and criteria importance through intercriteria correlation (IEW-CRITIC) method are used to determine weights. Finally, CoCoSo is applied to reliably rank the parameter combinations. The results show that a printing temperature of 240°C, a layer thickness of 0.3mm, and an infill density of 60% achieve the best overall mechanical properties across different raster angles, improving performance by approximately 10.7%. The effectiveness of the proposed method is further validated through comparison with existing methods and scanning electron microscopy analysis. This study provides a practical reference for complex decision-making in the FDM printing of recycled composites.