Search Results (136)

Hybrid machining has considerable potential for industrial applications. The process allows the limitations of additive manufacturing to be reduced and high-precision components to be produced. This article discusses tests determining the impact of 3D printing parameters, machining parameters, and selected milling tools on achieving defined surface roughness values in parts made of PETG (polyethylene terephthalate glycol). Perpendicular-shaped samples were printed by fused deposition modelling (FDM) using variable layer heights of 0.1 mm and 0.2 mm and variable feed rates of 90, 100, 110, and 120 mm/s. Surface roughness values, topography, and Abbott–Firestone curves were determined using a Keyence VR-6000 profilometer. Straight grooves were machined in the test samples using a DMG MORI CMX 600V milling machine with a rotary burr, single-edge spiral burr cutter and spiral endmill. The microstructure was examined using a Motic inverted microscope. The surface roughness parameters of the grooves were investigated. The results confirmed that the use of hybrid machining (with a printed layer height L_h = 0.1 mm, V_feed = 120 mm/s, and a cutter–rotary burr) allows for lower surface roughness parameters, i.e., Ra = 1.54 μm. The relationships developed between printing, cutting, and milling tool parameters can be employed to predict the roughness parameters of filaments with similar characteristics. Full article

Additive manufacturing via Fused Filament Fabrication (FFF) has enabled the development of functional components with customized mechanical properties. In this context, the use of polymers with flame-retardant additives offers an ideal solution for sectors such as aerospace, where fire resistance is a top priority. However, the tribological properties of these materials have not yet been sufficiently studied, despite their relevance in applications subjected to friction or wear. This study analyzes the tribological behavior of parts manufactured using PETG (Polyethylene Terephthalate Glycol) and flame-retardant PETG (PETG FP) through dry condition Ball-on-Disk tests. The influence of manufacturing parameters such as extrusion temperature and layer height on the coefficient of friction (CoF), surface wear, and roughness is investigated. The results show that PETG FP exhibits an increased CoF compared to conventional PETG, although it demonstrates more stable behavior at elevated temperatures. Statistical analysis via ANOVA reveals that material type and layer height significantly affect tribological properties, while temperature plays a secondary role. This study provides key insights for the selection of polymeric materials in environments with critical functional demands. Full article

Additive manufacturing (AM), particularly fused deposition modeling (FDM) 3D printing, has emerged as a versatile and accessible technology for prototyping and functional part production across a wide range of industrial applications. One of the critical performance-limiting factors in AM is the chemical resistance of thermoplastic materials, which directly influences their structural integrity, durability, and suitability in chemically aggressive environments. This study systematically investigates the chemical resistance of eight different widely utilized FDM filaments—acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), polyamide (PA, Nylon), polycarbonate (PC), polyethylene terephthalate glycol (PETG), polylactic acid (PLA), polypropylene (PP), and polyvinyl butyral (PVB)—by examining their tensile strength and impact resistance after immersion in representative chemical agents: distilled water, ethanol (99.5%), isopropyl alcohol (75% and 99%), acetic acid (8%), hydrochloric acid (37%), hydrogen peroxide (30%), and acetone (99.5%). Quantitative mechanical testing was conducted in accordance with ASTM D638 and ASTM D256 standards, and statistical variability was accounted for using triplicate measurements with standard deviation analysis. The results reveal that PP exhibits the highest chemical resilience, retaining over 97% of its mechanical properties even after 7 days of immersion in aggressive solvents like acetone. PETG and ASA also demonstrated quite successful stability (>90% retention) in mildly corrosive environments such as alcohols and weak acids. In contrast, PLA, due to its low crystallinity and polar ester backbone, and PVB, due to its high amorphous content, showed substantial degradation: tensile strength losses exceeding 70% and impact resistance dropping below 20% in acetone. Moderate resistance was observed in ABS and PC, which maintained structural properties in neutral or weakly reactive conditions but suffered mechanical deterioration (>50% loss) in solvent-rich media. A strong correlation (r > 0.95) between tensile and impact strength reduction was found for most materials, indicating that chemical attack affects both static and dynamic mechanical performance uniformly. The findings of this study provide a robust framework for selecting appropriate 3D printing materials in applications exposed to solvents, acids, or oxidizing agents. PP is recommended for harsh chemical environments; PETG and ASA are suitable for moderate exposure scenarios, whereas PLA and PVB should be limited to low-risk, esthetic, or disposable applications. Full article

In this study, the mechanical behavior and interfacial bonding characteristics of multi-material composites produced using the Hybrid Fused Deposition Modeling (HFDM) technique were systematically investigated. Polylactic Acid (PLA), Polyethylene Terephthalate Glycol (PETG), and Acrylonitrile Butadiene Styrene (ABS) filaments were utilized within a single structure to explore the effects of material combinations on mechanical performance. Specimens were fabricated using two distinct levels of infill density (50–100%) and raster angle (45–90°) to evaluate the influence of these parameters on tensile strength, flexural resistance, and impact toughness. Experimental tests were conducted following ASTM standards, and microstructural examinations were performed using Scanning Electron Microscopy (SEM) to assess interfacial adhesion between different polymers. The results revealed that PETG demonstrated the highest tensile strength among single-material samples, while the PLA-PETG-ABS configuration exhibited notable mechanical stability among hybrid structures. Increasing infill density and raster angle significantly enhanced mechanical performance across all configurations. SEM analyses confirmed that interfacial bonding quality critically affected structural integrity, with better adhesion observed in PLA–PETG interfaces compared to PLA–ABS transitions. The potential of HFDM in developing tailored multi-material components with optimized mechanical properties offers valuable insights for the advancement of functional additive manufacturing applications in engineering fields. Full article

The subject of the conducted study was primarily focused on the development of a new type of polymer blend modified with the use of nanosized fillers. The research concept involved the use of polycarbonate/polyethylene terephthalate glycol (PETG/PC) blends modified with the EBA-GMA impact modifier (ethylene–butylene–acrylonitrile copolymer) and three different types of nanofillers: montmorillonite (MMT), halloysite (HNT), and carbon nanotubes (CNT) of two types. The combination of PC, PETG, and EBA phases was used in order to achieve enhanced mechanical performance and stable processing properties. The results of the conducted study revealed that for the toughened PETG/PC/EBA blends, the impact resistance was strongly improved from the reference by 1.5 kJ/m² to 15 kJ/m². However, the results for the nanocomposites revealed that the MMT and HNT additions were limiting the impact strength. In contrast, the Charpy test results for CNT were again close to 15 kJ/m². The results of the thermal resistance measurements again revealed more favorable properties for CNT-modified PETG/PC/EBA blends. Full article

The present study evaluates the viability of fabricating unmanned aerial vehicle (UAV) propellers using fused filament fabrication (FFF), with an emphasis on low-cost, desktop-scale production. The study’s backdrop is the recent adoption of UAVs and advancements in additive manufacturing. While the scope targets accessibility for individual and small-scale users, the results have broader implications for scalable UAV propulsion systems. The research was conducted within an experimental UAV development framework aimed at optimizing propeller performance through strategic material selection, geometrical design optimization, and additive manufacturing processes. Six propeller variants were manufactured using widely available thermoplastic polymers, including polyethylene terephthalate glycol-modified (PETG) and thermoplastic polyurethane (TPU), as well as photopolymer-based propellers fabricated using vat photopolymerization, also known as digital light processing (DLP). Mechanical and aerodynamic characterizations were performed to assess the structural integrity, flexibility, and performance of each material under dynamic conditions. Two blade configurations, a toroidal propeller with anticipated aerodynamic advantages and a conventional tri-blade propeller (Gemfan 51466-3)—were comparatively analyzed. The primary contribution of this work is the systematic evaluation of performance metrics such as thrust generation, acoustic signature, mechanical strength, and thermal stress imposed on the electrical motor, thereby establishing a benchmark for polymer-based propeller fabrication via additive manufacturing. The findings underscore the potential of polymeric materials and layer-based manufacturing techniques in advancing the design and production of UAV propulsion components. Full article

Gradient porous structures (GPS) offer significant mechanical and functional advantages over homogeneous counterparts. This paper proposes a computational design framework utilizing spatial Voronoi diagrams to create lightweight, stress-responsive spatial frames optimized for architectural double-curvature arched shell roofing components. The method integrates Solid Isotropic Material with Penalization (SIMP)-based topology optimization (TO) to establish initial stress-informed material distributions, adaptive Voronoi control point (CP) placement guided by localized stress data, and a bi-objective genetic algorithm (GA) optimizing maximum and average displacement. Following optimization, a weighted Lloyd relaxation (LR) refines Voronoi cells into spatial frameworks with varying densities corresponding to stress gradients. Finite Element Analysis (FEA) demonstrates that the optimized Voronoi-driven GPS achieves notable improvements, revealing up to 79.7% material volume reduction and significant improvement in structural efficiency, achieving a stiffness-to-weight ratio (SWR) exceeding 2200 in optimized configurations. Furthermore, optimized structures consistently maintain maximum von Mises (MVM) stresses below 20 MPa, well within the allowable yield strength of the Polyethylene Terephthalate Glycol (PETG) material (53 MPa). The developed framework effectively bridges structural performance, material efficiency, and aesthetic considerations, offering substantial potential for application in advanced, high-performance architectural systems. Full article

Following the rising popularity of Unmanned Aerial Vehicles (UAVs) among large-scale users, in the form of domestic as well as professional drones, with applications in domains such as safety (e.g., surveillance drones), terrain mapping (using geo-scanning UAVs), videography drones, and high performance drones used in FPV (First Person View) drone competitions—as well as the rising wide accessibility of Fused Filament Fabrication (FFF)—especially considering the recent apparition and popularization of 3D printers capable of displaying exponential increases in performance metrics, the present work takes into consideration the practice of fabricating UAV propellers by means of FFF, focusing on the theoretical, as well as on the practical aspects of the roughness and quality observed at the level of the resulting surfaces. The paper proposes a set of propeller configurations obtained by combining popular propeller geometries, such as the Gemfan 51466-3 three-bladed propeller and the novel Toroidal propeller model, with a range of different fabrication materials, such as the Polyethylene Terephthalate Glycol (PETG) filament and the Polylactic Acid (PLA) filament. The main aim of the study is to reveal observations on the influence that the surface quality has on the performance metrics of a propeller. Based on the practical work, which aims to develop a comparative study between two drone propeller geometries manufactured by a nonconventional process, 3D printing, the practical applications in the study were carried out using low-cost equipment in order to evaluate the results obtained in a domestic setting. The study involves the identification of the noise values produced by the two geometries due to the roughness of the propeller surfaces. Full article

Interchain exchange, proceeded by the transesterification mechanism, allows one to obtain polyethylene terephthalate-based polyester products, bypassing the stage of molecular weight reduction and polycondensation used in classical methods of chemical recycling. A kinetic model is presented, which describes the change in the concentrations of bound and terminal units of ethylene glycol from PET and glycol from another polyester, as well as free molecules of ethylene glycol and another glycol, during transesterification reactions for the first time. Experimental data on the dependence of the degree of randomness and conversion on timeduring the interaction of polyethylene terephthalate and oligodiethylene terephthalate with terminal hydroxyl groups with a number-average molecular weight of 860 g/mol in different ratios were obtained. Molecular weight characteristics of the products of PET and oligoesters with hydroxyl end group interchain exchange, with number-average molecular weights from 610 to 860 g/mol, were also investigated. The simulation results were also compared with published data on the dependence of the degree of randomness and conversion on time during ether exchange in PET/PEN blends. The developed kinetic model was found to be in agreement with the experimental data. Full article

Osteoporosis and bone defects are commonly observed in postmenopausal women, often linked to decreased folic acid levels, which play a crucial role in bone metabolism and regeneration. This study investigates 3D-printed polyethylene terephthalate glycol (PETG)-based porous scaffolds impregnated with chitosan (CS), hydroxyapatite (HAp), and folic acid (FA) for bone tissue engineering applications. The PETG-CS scaffold serves as the primary structural framework, with HAp incorporated to enhance bioactivity through its osteoconductive and osteoinductive properties. FA was included to address potential deficiencies in bone quality and to stimulate cellular differentiation. The scaffolds were fabricated using precise 3D printing techniques, yielding structures with controlled porosity. Physicochemical analyses confirmed the successful integration of HAp and FA into the PETG-CS matrix. Biological evaluations using preosteoblast cell lines demonstrated enhanced cell viability, proliferation, and biocompatibility of the scaffolds. These findings highlight the promising applications of PETG-CS-HAp-FA scaffolds in bone tissue engineering, providing a platform for future investigations into personalized regenerative therapies. Full article

The materials used as filaments for additive techniques should exhibit various properties depending on the application and the requirements. The motivation for this study was the need to obtain a filament exhibiting appropriate aesthetic (metal-like) and mechanical properties. Glycol-modified poly(ethylene terephthalate) copolymer (PETG) and micrometric steel powder were used for composite preparation. Subsequently, the obtained material was used as a filament for 3D printing, i.e., by fused deposition modeling (FDM) technique. The physicochemical properties of the obtained filaments were determined, such as morphology (roughness), moisture sorption ability, thermal properties, and mechanical performance (tensile and compressive strength). Importantly, the metal filler did not modify the thermal properties of the polyester matrix, indicating that the filament containing steel microfiller could be processed using the same parameters as for neat PETG. The thermal stability was slightly enhanced after steel powder addition (for 13 wt.% content, the temperature of 75% weight loss was 466 °C; for comparison, that for the reference sample was 446 °C). The reinforcing effect of steel microfiller was noted based on mechanical performance measurements. The steel particles acted as a stiffening agent; the highest maximal tensile strength was observed for the composite with 3 wt.% steel powder content (ca. 68 MPa). Further increasing the microfiller load resulted in a slight decrease in the value of this parameter. A different trend was reported considering the compressive strength, i.e., the value of this parameter increased with steel content. Based on the obtained results, the new PETG composites could be applied as structural materials. Full article

Hard carbon (HC) is considered to be a highly promising anode material for sodium-ion batteries. However, the synthesis conditions and pore structure regulation are still challenging for high-capacity sodium-ion storage. In this study, HCs using polyethylene glycol terephthalate (PET) as a carbon resource and ZnO as a nanopore template were synthesized and systematically investigated. By optimizing the additive amount of zinc gluconate, the starting material for ZnO, PET-derived HCs with a proper mesoporous structure were obtained. The as-prepared hard carbon demonstrated a high reversible capacity of 389.42 mAh·g⁻¹ at 20 mA·g⁻¹, with the plateau capacity accounting for 68%. After 75 cycles, the discharge capacity stabilized at 367.73 mAh·g⁻¹ with a retention ratio of 89.4%. The rate performance test indicated that a proper mesopore structure helped to improve the sodium-ion diffusion coefficient, effectively enhancing the charge–storage kinetics. This work provides a promising strategy for converting PET into valuable carbon materials for application in the field of renewable energy technology. Full article

This study aimed to develop a biochar-modified polyethylene terephthalate glycol (PETG) composite for 3D printing. Biochar prepared from olive tree prunings was compounded with PETG at different loadings and then processed into filaments through a controlled extrusion process. The resultant filaments were used to print test specimens, which were characterized thoroughly by mechanical, thermal, morphological, and rheological methods. The tensile strength (17.8%), flexural strength (15.9%), impact resistance (20.9%), and thermal stability of the biochar-reinforced composites were substantially improved. Overall, the 6.0 wt.% biochar compound exhibited the highest improvement. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed the excellent dispersion of biochar in the PETG matrix. The results demonstrated that biochar is an effective, environmentally friendly material to use as a reinforcing agent for additive manufacturing. The PETG/biochar composites have a promising future for various industrial applications, offering sustainable alternatives with superior performance characteristics. Full article

The amount of non-revenue water, mostly due to leakage, is around 126 billion cubic meters annually worldwide. A more efficient wastewater management strategy would use a parametric design for on-demand, customized pipe fittings, following the principles of distributed manufacturing. To fulfill this need, this study introduces an open-source parametric design of a 3D-printable easy-connect pipe fitting that offers compatibility with different dimensions and materials of pipes available on the market. Custom pipe fittings were 3D printed using a RepRap-class fused filament 3D printer, with polylactic acid (PLA), polyethylene terephthalate glycol (PETG), acrylonitrile styrene acrylate (ASA), and thermoplastic elastomer (TPE) as filament feedstocks for validation. The 3D-printed connectors underwent hydrostatic water pressure tests to ensure that they met the standards for residential, agricultural, and renewable energy production applications. All the printed parts passed numerous hydrostatic pressure tests. PETG couplings can tolerate up to 4.551 ± 0.138 MPa of hydrostatic pressure, which is eight times greater than the highest standard water pressure in the residential sector. Based on the economic analysis, the cost of 3D printing a pipe coupling is from three to seventeen times lower than purchasing a commercially available pipe fitting of a similar size. The new open-source couplings demonstrate particular potential for use in developing countries and remote areas. Full article

The ankle, a pivotal and intricate joint within human anatomy, is particularly susceptible to injuries, notably sprains, due to its complex structural composition and the substantial load it endures, especially among high-performance athletes, thereby necessitating the development of innovative, patient-specific rehabilitation solutions to address the challenges presented during the recovery process. In response to this, a non-surgical approach is proposed, involving the meticulous design and implementation of a personalized orthosis. It will be designed employing additive manufacturing with polyethylene terephthalate glycol (PETG), which facilitates immobilization while also enhancing breathability and comfort through the strategic incorporation of hexagonal holes. It demonstrates significant promise in its innovative design, customizability, and potential applicability, contributing to the broader field of biomechanics and orthopedic rehabilitation. Full article