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This paper investigates the geometric interchangeability and dimensional precision of parts fabricated using Fused Deposition Modeling (FDM), with a focus on gear manufacturing. By employing a substrate and two spur gears as test components, critical process parameters, including layer thickness, extrusion speed, and print temperature, were optimized to achieve enhanced accuracy. Geometric and dimensional tolerances such as straightness, roundness, and surface roughness were systematically evaluated using advanced metrological techniques. The results indicate that larger components demonstrate higher precision, with deviations for large and pinion gears ranging between -0.045 and 0.060 mm, and -0.150 and 0.078 mm, respectively. Analysis reveals that the anisotropic nature of the FDM process and thermal shrinkage significantly impact accuracy, particularly in smaller features. Residual stress analysis reveals that smaller components formed via FDM exhibit higher stress concentrations and dimensional deviations due to voids and uneven thermal contraction, whereas larger components and flat substrates achieve better stress distribution and precision. The findings suggest that reducing material shrinkage coefficients and optimizing process parameters can enhance part quality, achieving dimensional tolerances within ±0.1 mm and geometric consistency suitable for practical applications. This research highlights the potential of FDM for precision manufacturing and provides insights into improving its performance for high-demand industrial applications.

Fabricating scaffolds using three-dimensional (3D) printing is an emerging approach in tissue engineering (TE), where filaments with a controlled arrangement are printed. Using fused deposition modeling in bone replacement enables the simulation of bone structure. However, the microenvironment created by the scaffold must meet specific requirements. These requirements aim to create an environment that promotes adhesion, proliferation, differentiation, and cell migration. One of the challenges in creating polylactic acid scaffolds is controlling the degradation rate to match the target tissue. This study investigates the degradation of scaffolds with different geometries and the relationship between scaffolds' geometry and degradation rate. These scaffolds are made of polylactic acid and prepared using 3D printing. The lattice geometry was exposed to acidic media with varying pH levels for 1 month, and pH2 was selected for all geometries for further investigation. The five selected geometries were then immersed in the desired acid for 2 months, and measurements were taken for wet weight, dry weight, morphology, molecular weight, and crystallinity during degradation. The results showed that the hexagonal sample had a 1.5% increase in wet weight, and the gyroid sample had a 1.2% increase, indicating that the wavy shapes had a higher fluid-holding capacity. The degradation analysis indicated that the hexagonal geometry had accelerated degradation compared to the other geometries. Based on these findings, it can be concluded that filament separation not only results in rapid cooling and prevents the recovery of the crystalline arrangement but also increases the surface area to volume ratio, allowing for more acid penetration and faster degradation. Finally, mechanical properties and in vitro evaluation were assessed for three selected geometries. On the 60th day, the hexagonal scaffold had the highest elastic modulus value of 105 ± 0.45 MPa, while the gyroid scaffold had the lowest value of 58.8 ± 0.40 MPa. The lattice scaffold had the highest amount of cell attachment, with 210.88 ± 0.35 cells surviving after 24 hours and 94.01 ± 0.18 cells surviving after 72 hours. These high viability rates indicate that the three scaffolds with the selected geometries are suitable for promoting cell growth., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: To propose comprehensive characterization methods of additive manufacturing (AM) materials for MV photon and MeV electron radiotherapy., Methodology: This study investigated 15 AM materials using CT machines. Geometrical accuracy, tissue-equivalence, uniformity, and fabrication parameters were considered. Selected soft tissue equivalent filaments were used to fabricate slab phantoms and compared with water equivalent RW3 phantom by delivering planar 6 & 10 MV photons and 6, 9, 12, 15, & 18 MeV electrons. Finally, a 3D printed CT-Electron Density characterization phantom was fabricated., Results: Materials used to print test objects can simulate tissues from adipose (relative electron density, ρ e =0.72) up to near inner bone-equivalent (ρ e =1.08). Lower densities such as breast and lung can be simulated using infills from 90 % down to 30 %, respectively. The gyroid infill pattern shows the lowest CT number variation and is recommended for low infill percentage printing. CT number uniformity can be observed from 40 % up to 100 % infill, while printing orientation does not significantly affect the CT number. The measured doses using the 3D printed phantoms show to have good agreement with TPS calculated dose for photon (< 1 % difference) and electron (< 5 % difference). Varying the printed slab thicknesses shows very similar response (< 3 % difference) compared with RW3 slabs except for 6 MeV electrons. Lastly, the fabricated CT-ED phantom generally matches the lung- up to the soft tissue- equivalence., Conclusion: The proposed methods give the outline for characterization of AM materials as tissue-equivalent substitute. Printing parameters affect the radiological quality of 3D-printed object., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.)

Background: High tibial osteotomy (HTO) is a surgical procedure for treating certain knee conditions. Proper execution of HTO can preserve joint function and delay or avoid the need for total knee replacement. This study compared different 3D printing techniques (fused deposition modeling, selective laser sintering, and direct metal laser sintering) and a navigation system for their suitability in assisting HTO surgeries., Methods: Tibial saw-bones were used as models, and surgical guides and the navigation system were employed during the procedures. Six parameters (planning time, manufacturing time, delivery time, material cost, operation time, and accuracy) were evaluated. One-way analysis of variance (ANOVA) and t-test were used for the analysis., Results: The results showed that the metal surgical guides had the highest accuracy (angle differences mean, 2.4°) and operation time (mean 9.75 min), followed by plastic guides, classic guides, and the navigation system. The differences in accuracy were attributed to factors like rigidity, melting point, and errors during incisions., Conclusions: The study recommended metal surgical guides as the best option for assisting HTO due to their accuracy and operation time. And the results have implications for orthopedic surgeons performing HTO surgeries, as they can use this information to improve postoperative outcomes, such as mechanical axis alignment and quality of life for HTO patients., (© 2024 The Author(s). Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

To address the anisotropy of mechanical properties and the challenge of removing support materials in lattice structures fabricated using fused deposition modeling (FDM), this study is inspired by traditional woodworking mortise and tenon joints. A hexagonal interlocking mortise lattice structure was designed, and mortise and tenon lattice structures (MTLSs) with various parameters were fabricated. Compared with the traditional integrated forming lattice structure (IFLS), the MTLS exhibits maximum reductions in side surface roughness (Ra), printing time, and material consumption of 74.87%, 25.55%, and 52.21%, respectively. In addition to enhancing surface quality and printing efficiency, the MTLS also exhibited superior mechanical properties. The uniaxial compression test results show that the specific strength, energy absorption (EA), and specific energy absorption (SEA) of the MTLS exhibit maximum increases of 51.22%, 894.59%, and 888.39%, respectively, compared with the IFLS. Moreover, the effects of strut angle and thickness on the lattice structure were analyzed. Smaller strut angles and larger strut thicknesses endowed greater strength, while smaller angles contributed to higher energy absorption. This study proposes a novel approach for designing lattice structures in additive manufacturing.

In the V-bending of sheet metals using a pair of plastic punch and die manufactured by a 3D printer, the effects of two different dimensions designed with the same tool geometry on the deformation behaviors of the punch, die, and sheet were evaluated. The deformation behavior and strain distribution of the punch, die, and sheet were analyzed using a digital image correlation method. Sheets from pure aluminum to ultra-high-strength steel were bent using the two tools with different spans; one was designed on the assumption of tool steel material, and the other was designed on the assumption of plastic material. In both tools, the large compressive strain appeared around the center of the punch tip and on the corners of the die. The tools with a long span for the plastic material gave a lower bending force and small deformation of the plastic tools. The angle difference between a bent sheet at the bottom dead center and a tool was smaller for the tools with the long span, although the springback in the bent sheet appeared. It was found that the design method on the assumption of the plastic material is effective for the V-bending plastic tools.

Background/Objectives : Chagas disease is a neglected tropical disease caused by infection with the parasite Trypanosoma cruzi . Benznidazole and nifurtimox are the only approved drugs for treating this condition, but their low aqueous solubility may lead to erratic bioavailability. This work aimed for the first time to formulate tablets of nifurtimox by hot melt extrusion coupled with 3D printing as a strategy to increase drug dissolution and the production of tablets with dosage on demand. Methods : Different pharmaceutical-grade polymers were evaluated through film casting, and those with promising nifurtimox amorphization capacity were further used to prepare filaments by hot melt extrusion. The printability of the obtained filaments was tested, and the polyvinyl alcohol filament was further used for printing tablets containing 120 and 60 mg of nifurtimox. Results : Three-dimensional tablets showed a remarkable improvement in the drug dissolution rate compared to commercial tablets and a dissolution efficiency 2.8 times higher. In vivo studies were carried out on Swiss mice. Parasitemia curves of nifurtimox printed tablets were significantly superior to the pure drug. Moreover, NFX 3D tablets provided a similar Trypanosoma cruzi reduction in plasmatic concentration to benznidazole, the gold-standard drug for acute-phase treatment of the Chagas disease. Conclusions : The findings of this work showed that hot melt extrusion coupled with 3D printing is a promising alternative for increasing nifurtimox biopharmaceutical properties and an attractive approach for personalized medicine.

Addressing the high cost and long cycle associated with the multistep digital restoration process involving 3D printing technology, we proposed the 3D pen as an innovative strategy for rapid bone repair. Capitalizing on the low melting point characteristic of polycaprolactone (PCL), we introduced, for the first time, the novel concept of directly constructing scaffolds at bone defect sites using 3D pens. In this in vitro study, we meticulously evaluated both the mechanical and biological properties of 3D pen-printed PCL scaffolds with six distinct textures: unidirectional (UNI) (0°, 45°, 90°), bidirectional (BID) (-45°/45°, 0°/90°), and concentric (CON). The bone repair scaffold creation process was simulated using a fused deposition modeling (FDM) 3D printer and a 3D pen by creating a cattle bone defect model to compare the achieved scaffold time efficiency and accuracy. Mechanical test results revealed that 3D pen-printed scaffolds with different textures exhibited varying results in four tests, except the shear bond test. Optimal scaffold strength was consistently achieved when printing parallel to the applied force. Regarding biological properties, these scaffolds exhibited consistent cell viability over time and showcased excellent cell attachment capabilities overall. Furthermore, cells grew regularly along the printed filaments, with additional living cells at high elevations observed. Additionally, the 3D pen method outperformed traditional digital technology with an FDM 3D printer concerning accuracy and speed. These findings underscored the tremendous potential of the 3D pen in the realm of medical science, specifically within the domain of bone tissue engineering, characterized by its low cost, high speed, and convenience., (© 2025 Wiley Periodicals LLC.)

Introduction: This study aims to develop immediate release tablet formulations of lornoxicam (LRX) using hot melt extrusion (HME)-based fused deposition modeling (FDM) focusing on the adjustment of drug release by arranging infill densities and evaluating microcrystalline cellulose II (MCC II) as a disintegrating agent for HME-FDM purposes. LRX is a poorly soluble drug that exhibits pH-dependent solubility with a high thermal degradation temperature. These characteristics make it an ideal model drug for the HME-based FDM technique., Methods: Various filament formulations were extruded using an extruder, and suitable filaments were used to produce 3D-printed tablets. Filaments and tablets were characterized. Dissolution studies were performed on tablets with different infill densities. DSC, FTIR, XRD, and SEM analyses were conducted., Results: Although the solubility of LRX increases with pH, disintegrating agents such as MCC II had a more significant effect on the dissolution of LRX than sodium bicarbonate, which was used as the alkalinizing pore-forming agent. Dissolution studies revealed that the dissolution of LRX was enhanced by tablet erosion. Tablet erosion increased as the infill density decreased, and an immediate release profile was reached with tablets having 25% infill density. Despite the availability of conventional immediate release LRX tablets, this newly developed formulation offers the potential to be modulated for personalized therapy via the 3D printing technique., Conclusion: This study demonstrates the feasibility of HME-based FDM printing technology for producing immediate-release LRX tablets with consistent quality, highlighting the utilization of MCC II as a disintegrating agent that enhances LRX dissolution in this process.

In recent years, with the increasing patient population, the need for complex and patient-centric medications has increased enormously. Traditional manufacturing techniques such as direct blending, high shear granulation, and dry granulation can be used to develop simple solid oral medications. However, it is well known that "one size fits all" is not true for pharmaceutical medicines. Depending on the age, sex, and disease state, each patient might need a different dose, combination of medicines, and drug release pattern from the medications. By employing traditional practices, developing patient-centric medications remains challenging and unaddressed. Over the last few years, much research has been conducted exploring various additive manufacturing techniques for developing on-demand, complex, and patient-centric medications. Among all the techniques, nozzle-based additive manufacturing platforms such as pressure-assisted microsyringe (PAM) and fused deposition modeling (FDM) have been investigated thoroughly to develop various medications. Both nozzle-based techniques involve the application of thermal energy. However, PAM can also be operated under ambient conditions to process semi-solid materials. Nozzle-based techniques can also be paired with the hot melt extrusion (HME) process for establishing a continuous manufacturing platform by employing various in-line process analytical technology (PAT) tools for monitoring critical process parameters (CPPs) and critical material attributes (CMAs) for delivering safe, efficacious, and quality medications to the patient population without compromising critical quality attributes (CQAs). This review covers an in-depth discussion of various critical parameters and their influence on product quality, along with a note on the continuous manufacturing process, quality by design, and future perspectives.

This article describes an innovative thermal insulation barrier in the form of a sandwich panel manufactured using 3D FDM printing technology. The internal structure (core structure) of the barrier is based on the Kelvin foam model. This paper presents the influence of the parameters (the height h and the porosity P of a single core cell) of the barrier on its properties (thermal conductivity, thermal resistance, compressive strength, and quasi-static indentation strength). The dominant influence of the porosity of the structure on the determined physical properties of the fabricated samples was demonstrated. The best insulation results were obtained for single-layer composites with a cell height of 4 mm and a porosity of 90%, where the thermal conductivity coefficient was 0.038 W/(m·K) and the thermal resistance 0.537 (m 2 ·K)/W. In contrast, the best compressive strength properties were obtained for the 50% porosity samples and amounted to about 350 MPa, while the moduli for the 90% porosity samples were 14 times lower and amounted to about 26 MPa. The porosity (P) of the composite structure also had a significant effect on the punch shear strength of the samples produced, and the values obtained for the 90% porosity samples did not exceed 1 MPa. In conclusion, the test showed that the resulting 3D cellular composites offer an innovative and environmentally friendly approach to thermal insulation.

Research on shape memory materials (SMM) or smart materials, along with advancements in printing technology, has transformed three-dimensional (3D) printing into what we now refer to as 4D printing. In this context, the addition of time as a fourth dimension enhances 3D printing. 4D printing involves the creation of 3D-printed objects that can change their shapes into complex geometries when influenced by external stimuli such as temperature, light, or pH over time. Currently, the use of smart materials in 4D printing is being explored extensively across various fields, including automotive, wearable electronics, soft robotics, food, mechatronics, textiles, biomedicine, and pharmaceuticals. A particular focus is on designing and fabricating smart drug delivery systems (DDS). This review discusses the evolution of 3D printing into 4D printing, highlighting the differences between the two. It covers the history and fundamentals of 4D printing, the integration of machine learning in 4D printing, and the types of materials used, such as stimuli-responsive materials (SRMs), hydrogels, liquid crystal elastomers, and active composites. Moreover, it presents various 4D printing techniques. Additionally, the review highlights several smart DDS that have been fabricated using 4D printing techniques. These include tablets, capsules, grippers, scaffolds, robots, hydrogels, microneedles, stents, bandages, dressings, and other devices aimed at esophageal retention, gastro-retention, and intravesical DDS. Lastly, it elucidates the current limitations and future directions of 4D printing., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Despite Fused Deposition Modeling (FDM) being an economical 3D printing method known for its material versatility and ease of use, the mechanical performance of FDM-produced components is significantly influenced by process parameter settings. This study investigated the effects of the layer thickness, raster angle, build orientation, and extrusion temperature on the ultimate tensile strength (UTS) and elastic modulus of Polylactic Acid (PLA) specimens using Taguchi methods, with significance analyzed through analysis of variance (ANOVA). The results indicated that the build orientation is the primary factor affecting both the UTS and elastic modulus, with a flat orientation yielding the best performance. ANOVA showed that the build orientation, raster angle, and extrusion temperature significantly influence the UTS, with the build orientation contributing 98.16%. For the elastic modulus, the build orientation and raster angle were significant, contributing 94.83% and 1.76%, respectively. The optimal parameters were a 0.16 mm layer thickness, flat build orientation, 30°/-60° raster angle, and 200 °C extrusion temperature, resulting in predicted UTS and elastic modulus values with error percentages of 4.33% and 2.74%, respectively, compared to experimental values. The regression model demonstrated high predictive accuracy, with R-squared values of 99.71% for the UTS and 99.52% for the elastic modulus.

In the past decade, 4D printing has received attention in the aerospace, automotive, robotics, and biomedical fields due to its lightweight structure and high productivity. Combining stimulus-responsive materials with 3D printing technology, which enables controllable changes in shape and mechanical properties, is a new technology for building smart bearing structures. A multilayer smart truss structural component with self-sensing function is designed, and an internal stress calibration strategy is established to better adapt to asymmetric loads. A material system consisting of continuous carbon fibers and polylactic acid was constructed, and an isosceles trapezoidal structure was chosen as the basic configuration of the smart component. The self-inductive properties are described by analyzing the relationship between the pressure applied to the specimen and the change in the specimen's own resistance. Load-carrying capacity is realized by electrically heating the continuous carbon fibers in the component. Thermal deformation calibrates internal stress and enhances the load-carrying ability of the component over 50%. The experimental results demonstrate that the truss structure designed in this paper has strong self-induction, self-driving ability, and asymmetric load adaptation ability at the same time. This verifies that the 4D-printed smart component can be used as a load-carrying element, which broadens the application scope of smart components.

Usage of continuous fibers as a reinforcement would definitely increase the mechanical properties of 3D-printed materials. The result is a continuous fiber-reinforced composite obtained by additive manufacturing that is not limited to prototyping or non-structural applications. Among the available continuous reinforcing fibers, basalt has not been extensively studied in 3D printing. This material is attractive due to its natural origin, good mechanical properties, impact strength, and high chemical and thermal resistance. In this work, a continuous basalt fiber co-extruded composite obtained by fused filament fabrication was characterized both thermally and mechanically, concerning the in-plane tensile properties. The degree of anisotropy of the material was also assessed, both qualitatively and quantitatively. The 3D-printed composite showed longitudinal properties, which were 15 times higher than the pure matrix, thus meeting structural requirements. On the other hand, transverse and shear properties were much lower than longitudinal ones, thus leading to a strongly anisotropic material. This was also confirmed by the anisotropy evaluation that was performed numerically and graphically using an innovative approach. This behavior affects the design of 3D-printed parts; thus, an optimized continuous fiber deposition is necessary for structural applications.

The current study explores, for the first time, an eco-friendly solution casting method using a green solvent, ethyl acetate, to prepare feedstock/filaments from polylactic acid (PLA) biopolymer reinforced with carbon nanotubes (CNTs), followed by 3D printing and surface activation for biosensing applications. Comprehensive measurements of thermal, electrical, rheological, microstructural, and mechanical properties of developed feedstock and 3D-printed parts were performed and analyzed. Herein, adding 2 wt.% CNTs to the PLA matrix marked the electrical percolation, achieving conductivity of 8.3 × 10 -3 S.m -1 , thanks to the uniform distribution of CNTs within the PLA matrix facilitated by the solution casting method. Rheological assessments paralleled these findings; the addition of 2 wt.% CNTs transitioned the nanocomposite from liquid-like to a solid-like behavior with a percolated network structure, significantly elevating rheological properties compared to the composite with 1 wt.% CNTs. Mechanical evaluations of the printed samples revealed improvement in tensile strength and modulus compared to virgin PLA by a uniform distribution of 2 wt.% CNTs into PLA, with an increase of 14.5% and 10.3%, respectively. To further enhance the electrical conductivity and sensing capabilities of the developed samples, an electrochemical surface activation treatment was applied to as-printed nanocomposite samples. The field-emission scanning electron microscopy (FE-SEM) analysis confirmed that this surface activation effectively exposed the CNTs to the surface of 3D-printed parts by removing a thin layer of polymer from the surface, thereby optimizing the composite's electroconductivity performance. The findings of this study underscore the potential of the proposed eco-friendly method in developing advanced 3D-printed bio-nanocomposites based on carbon nanotubes and biopolymers, using a green solution casting and cost-effective material extrusion 3D-printing method, for electrochemical-sensing applications.

Fused deposition modeling (FDM) is well suited for microfluidic prototyping due to its low investment cost and a wide range of accessible materials. Nevertheless, most commercial FDM materials exhibit low chemical and thermal stability. This reduces the scope of applications and limits their use in research and development, especially for on-chip chemical synthesis. In this paper, we present FDM fabrication of microfluidic chips with polyvinylidene fluoride (PVDF) for applications that require high thermal or chemical resistance. Embedded microchannels with a minimum channel width and heights of ~200 µm × 200 µm were fabricated, and the resistance against common solvents was analyzed. A procedure was developed to increase the optical transmission to result in translucent components by printing on glass. Chips for fluid mixing were printed, as well as microreactors that were packed with a catalytically active phase and used for acetal deprotection with a conversion of more than 99%. By expanding the use of fluorinated polymers to FDM printing, previously challenging microfluidic applications will be conducted with ease at the lab scale.

This article examines the influence of various factors on the precision of 3D printed objects produced through Fused Filament Fabrication (FFF) using Polylactic Acid (PLA) as the primary material. While PLA is widely chosen for its compatibility with biological applications, it does suffer from limited dimensional accuracy. The study focuses on investigating the effects of four independent parameters, namely layer height, infill density, printing speed, and the number of top and bottom layers, on accuracy along the three axes of length, width, and depth. The research objective is to identify the optimal levels of these parameters that minimize dimensional errors across all axes. However, due to conflicting requirements among different dimensions, determining a comprehensive decision-making methodology presents a significant challenge. To address this issue, three distinct approaches are proposed, each offering a unique perspective and practical application. Interestingly, the outcomes of these approaches converge on a single solution. Among these parameters, printing speed emerges as the dominant factor, while, the number of layers is the least influential. Moreover, consistent shrinkage is observed in the length and width dimensions, with greater errors evident in longer dimensions. Overall, a preference for lower layer height and infill density, along with higher printing speed and increased top and bottom layers, is recommended. The study findings indicate that the most effective parameter selection for reducing errors in all dimensions involves a layer height of 0.2 mm, infill density of 60%, printing speed of 50 mm/s, and the use of four top and bottom layers., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

This paper investigates the optimization of tensile strength, tensile strength per unit weight, and tensile strength per unit time of polyethylene terephthalate glycol (PETG) material in fused deposition modeling (FDM) technology using the Taguchi method and analysis of variance (ANOVA). Unlike previous studies that typically focused on optimizing a single mechanical property, our research offers a multi-dimensional evaluation by simultaneously optimizing three critical quality characteristics: tensile strength, tensile strength per unit weight, and tensile strength per unit time. This comprehensive approach provides a broader perspective on both the mechanical performance and production efficiency, contributing new insights into the optimization of PETG in FDM. The Taguchi method (L16 45) was designed and executed, with the layer height, infill density, print temperature, print speed, and infill line direction as the control factors. Sixteen tensile tests were conducted, and ANOVA was employed to identify the main influencing factors for each quality characteristic. For the tensile strength, the infill density was found to have the greatest impact (48.45%), while the print temperature had the least impact (0.78%). The optimal parameter combination reduced the quality loss to 31.28% and standard deviation to 55.93%. For tensile strength per unit weight, the infill line direction had the greatest impact (87.22%), whereas the print temperature had the least impact (0.77%). The optimal parameter combination reduced the quality loss to 54.09% and standard deviation to 73.54%. Regarding the tensile strength per unit time, the layer height had the greatest impact (82.12%), while the print temperature had the least impact (0.08%). The optimal parameter combination reduced the quality loss to 10.81% and standard deviation to 32.87%.

Background/objectives: Three-dimensional printing technology has emerging interest in pharmaceutical manufacturing, offering new opportunities for personalized medicine and customized drug delivery systems. Fused deposition modeling (FDM) is highly regarded in the pharmaceutical industry because of its cost effectiveness, easy operation, and versatility in creating pharmaceutical dosage forms. This review investigates different methods of incorporating active pharmaceutical ingredients (APIs) into filament matrices for use in fused deposition modeling (FDM) 3D printing., Methods: Two electronic databases, the Web of Science and PubMed, were utilized to survey the literature. The selected keywords for this review were as follows: fused filament fabrication OR fused deposition modeling OR FDM OR FFF AND 3D printing AND loading techniques OR impregnation techniques AND solid dosage form., Results: This paper evaluates various loading techniques such as soaking, supercritical impregnation, microwave impregnation, and hot-melt extrusion, focusing on their effectiveness and capacity for drug incorporation. Additionally, this review includes a thorough risk assessment of the extrusion process using Ishikawa and SWOT analyses., Conclusions: Overall, this review provides comprehensive insights into the latest advancements in 3D printing for pharmaceutical applications and identifies key areas for future research and development.

Purpose: The application of 3D printing technology in drug delivery is often limited by the challenges of achieving precise control over drug release profiles. The goal of this study was to apply surface equations to construct 3D printed tablet models, adjust the functional parameters to obtain multiple tablet models and to correlate the model parameters with the in vitro drug release behavior., Methods: This study reports the development of 3D-printed tablets using surface geometries controlled by mathematical functions to modulate drug release. Utilizing fused deposition modeling (FDM) coupled with hot-melt extrusion (HME) technology, personalized drug delivery systems were produced using thermoplastic polymers. Different tablet shapes (T1-T5) were produced by varying the depth of the parabolic surface (b = 4, 2, 0, -2, -4 mm) to assess the impact of surface curvature on drug dissolution., Results: The T5 formulation, with the greatest surface curvature, demonstrated the fastest drug release, achieving complete release within 4 h. In contrast, T1 and T2 tablets exhibited a slower release over approximately 6 h. The correlation between surface area and drug release rate was confirmed, supporting the predictions of the Noyes-Whitney equation. Differential Scanning Calorimetry (DSC) and Scanning Electron Microscope (SEM) analyses verified the uniform dispersion of acetaminophen and the consistency of the internal structures, respectively., Conclusions: The precise control of tablet surface geometry effectively tailored drug release profiles, enhancing patient compliance and treatment efficacy. This novel approach offers significant advancements in personalized medicine by providing a highly reproducible and adaptable platform for optimizing drug delivery., Competing Interests: Declarations. Competing Interest: No conflicts of interest., (© 2024. The Author(s).)

The manufacturing sector's interest in additive manufacturing (AM) methods is increasing daily. The increase in energy consumption requires optimization of energy consumption in rapid prototyping technology. This study aims to minimize energy consumption with determined production parameters. Four machine learning algorithms are preferred to model the energy consumption of the fused deposition modeling-based 3D printer. The real-time measured test sample data were trained, and the prediction model between the parameters of 3D fabrication and the energy consumption was created. The predicted model was evaluated using five performance criteria. These are mean square error (MSE), mean absolute error (MAE), root mean squared error (RMSE), R -squared ( R 2 ), and explained variance score (EVS). It has been seen that the Gaussian Process Regression model predicts energy consumption in the AM with high accuracy: R 2  = 0.99, EVS = 0.99, MAE = 0.016, RMSE = 0.022, and MSE = 0.00049., (Copyright 2023, Mary Ann Liebert, Inc., publishers.)

This study presents a novel approach to the development of high-performance supercapacitors through 3D printing technology. We synthesized a composite material consisting of silver-doped reduced graphene oxide (rGO) and dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANI), which was further blended with polylactic acid (PLA) for additive manufacturing. The composite was extruded into filaments and printed into circular disc electrodes using fused deposition modeling (FDM). These electrodes were assembled into symmetric supercapacitor devices with a solid-state electrolyte. Electrochemical characterization, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests, demonstrated considerable mass-specific capacitance values of 136.2 F/g and 133 F/g at 20 mV/s and 1 A/g, respectively. The devices showed excellent stability, retaining 91% of their initial capacitance after 5000 cycles. The incorporation of silver nanoparticles enhanced the conductivity of rGO, while PANI-DBSA improved electrochemical stability and performance. This study highlights the potential of combining advanced materials with 3D printing to optimize energy storage devices, offering a significant advancement over traditional manufacturing methods.

In terahertz (THz) optical systems, polymer-based manufacturing processes are employed to ensure product quality and the material performance necessary for proper system maintenance. Therefore, the precise manufacturing of system components, such as optical elements, is crucial for the optimal functioning of the systems. In this study, the authors investigated the impact of various 3D printing parameters using fused deposition modeling (FDM) on the optical properties of manufactured structures within the THz radiation range. The measurements were conducted on 3D printed samples using highly transparent and biocompatible cyclic olefin copolymer (COC), which may find applications in THz passive optics for "in vivo" measurements. The results of this study indicate that certain printing parameters significantly affect the optical behavior of the fabricated structures. The improperly configured printing parameters result in the worsening of THz optical properties. This is proved through a significant change in the refractive index value and undesirable increase in the absorption coefficient value. Furthermore, such misconfigurations may lead to the occurrence of defects within the printed structures. Finally, the recommended printing parameters, which improve the optical performance of the manufactured structures are presented.

A novel approach, i.e., Continuous Material Deposition on Filaments (CMDF), for the incorporation of active materials within 3D-printed structures is presented. It is based on passing a filament through a solution in which the active material is dissolved together with the polymer from which the filament is made. This enables the fabrication of a variety of functional 3D-printed objects by fused deposition modeling (FDM) using commercial filaments without post-treatment processes. This generic approach has been demonstrated in objects using three different types of materials, Rhodamine B, ZnO nanoparticles (NPs), and Ciprofloxacin (Cip). The functionality of these objects is demonstrated through strong antibacterial activity in ZnO NPs and the controlled release of the antibiotic Cip. CMDF does not alter the mechanical properties of FDM-printed structures, can be applied with any type of FDM printer, and is, therefore, expected to have applications in a wide variety of fields.

Polyetheretherketone (PEEK), a high-performance special engineering plastic, has gradually been used in bone substitutes due to its wear resistance, acid and alkali resistance, non-toxicity, radiolucency, and modulus close to that of human bone. However, its stable biphenyl structure determines strong biological inertness, thus artificial interventions are required to improve the biological activity of fabricated PEEK parts for better clinical applications. This study developed a novel strategy for grafting bioactive glass (BAG) onto the surface of PEEK through sulfonation reaction with concentrated sulfuric acid (H2SO4), aiming to improve the bioactivity of printed porous bone scaffolds manufactured by fused deposition modeling (FDM) to meet clinical individual needs. In vitro biological study was conducted on sulfonated polyetheretherketone-bioactive glass (SPEEK-BAG) scaffolds obtained by this strategy. The results demonstrated that the optimal modification condition was a 4-hour sulfonation reaction with 1 mol/L concentrated H2SO4 at high temperature and high pressure. The scaffold obtained under this condition showed minimal cytotoxicity, and the Ca/P molar ratio, yield compressive strength, and compressive modulus of this scaffold were 2.94 ± 0.02, 62.78 MPa, and 0.186 GPa respectively. The hydrophilicity and the biomineralization ability of PEEK modified by the proposed strategy were substantially improved. The SPEEK-BAG bone scaffolds exhibited excellent biocompatible properties, suggesting that the sulfonation reaction and BAG effectively enhanced the proliferation and differentiation of osteoblasts. The presented method provides an innovative, highly effective, and customized strategy to improve the biocompatibility and bone repair ability of printed PEEK bone scaffolds for virous biomedical applications., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Background/objectives: The pharmacy profession has undergone significant changes driven by advancements in patient care and healthcare systems. The FDA approval of Spritam ® (levetiracetam), the first 3D-printed drug, has sparked increased interest in the use of Fused Deposition Modeling (FDM) 3D printing for pharmaceutical applications, particularly in the production of polypills., Methods: This review provides an overview of FDM 3D printing in the development of pharmaceutical dosage forms, focusing on its operation, printing parameters, materials, additives, advantages, and limitations. Key aspects, such as the ability to personalize medication and the challenges associated with the technique, including drug stability at high temperatures, are discussed., Results: Fourteen studies relevant to FDM 3D-printed polypills were analyzed from an initial pool of 60. The increasing number of publications highlights the growing global interest in this technology, with the UK contributing the highest number of studies., Conclusions: FDM 3D printing offers significant potential for personalized medicine by enabling precise control over dosage forms and tailoring treatments to individual patient needs. However, limitations such as high printing temperatures and the lack of standardized GMP guidelines for large-scale production must be addressed to fully realize its potential in pharmaceutical manufacturing.

This review focuses on advancements in polymer science as it relates to three-dimensional (3D) and four-dimensional (4D) printing technologies, with a specific emphasis on applications in the biomedical field. While acknowledging the breadth of 3D and 4D printing applications, this paper concentrates on the use of polymers in creating biomedical devices and the challenges associated with their implementation. It explores integrative modeling and experimental insights driving innovations in these fields, focusing on sustainable manufacturing with biodegradable polymers, a comparative analysis of 3D and 4D printing techniques, and applications in biomedical devices. Additionally, the review examines the materials used in both 3D and 4D printing, offering a detailed comparison of their properties and applications. By highlighting the transformative potential of these technologies in various industrial and medical applications, the paper underscores the importance of continued research and development. The scope of this review also includes an overview of future research directions to address current challenges, enhance material capabilities, and explore practical applications.

This work aims at the determination of the coefficient of thermal expansion (CTE) of parts manufactured through the Fused Deposition Modeling process, employing fiber Bragg grating (FBG) sensors. Pure thermoplastic and composite specimens were built using different commercially available filament materials, including acrylonitrile butadiene styrene, polylactic acid, polyamide, polyether-block-amide (PEBA) and chopped carbon fiber-reinforced polyamide (CF-PA) composite. During the building process, the FBGs were embedded into the middle-plane of the test specimens, featuring 0° and 90° raster printing orientations. The samples were then subjected to thermal loading for measuring the thermally induced strains as a function of applied temperature and, consequently, the test samples' CTE and glass transition temperature (T g ) based on the recorded FBG wavelengths. Additionally, the integrated FBGs were used for the characterization of the residual strain magnitudes both at the end of the 3D printing process and at the end of each of the two consecutively applied thermal cycles. The results indicate that, among all tested materials, the CF-PA/0° specimens exhibited the lowest CTE value of 14 × 10 -6 /°C. The PEBA material was proven to have the most isotropic thermal response for both examined raster orientations, 0° and 90°, with CTE values of 117 × 10 -6 /°C and 108 × 10 -6 /°C, respectively, while similar residual strains were also calculated in both printing orientations. It is presented that the followed FBG-based methodology is proven to be an excellent alternative experimental technique for the CTE characterization of materials used in 3D printing.

Prototyping analytical devices with three-dimensional (3D) printing techniques is becoming common in research laboratories. The attractiveness is associated with printers' price reduction and the possibility of creating customized objects that could form complete analytical systems. Even though 3D printing enables the rapid fabrication of electrochemical sensors, its wider adoption by research laboratories is hindered by the lack of reference material and the high "entry barrier" to the field, manifested by the need to learn how to use 3D design software and operate the printers. This review article provides insights into fused deposition modeling 3D printing, discussing key challenges in producing electrochemical sensors using currently available extrusion tools, which include desktop 3D printers and 3D printing pens. Further, we discuss the electrode processing steps, including designing, printing conditions, and post-treatment steps. Finally, this work shed some light on the current applications of such electrochemical devices that can be a reference material for new research involving 3D printing., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

The current study focused on improving the properties of polylactic acid (PLA) for wider application in load-bearing scenarios. Various methods were explored to optimize the interaction between PLA and natural fibers, particularly wood fibers (WFs). Alkalized and epoxy-impregnated WFs were evaluated against untreated WFs and cellulose fibers in both injection molding (IM) and fused deposition modeling (FDM). FTIR analysis revealed the removal of hemicellulose and lignin in alkalized WFs and uniform epoxy curing. Addition of fibers reduced PLA's thermal stability while acting as nucleating agents. Additionally, fibers augmented the storage modulus of biocomposites, with alkalized fibers exhibiting the highest tensile modulus in IM. FDM samples with a 0° raster angle showed superior impact resistance compared to IM counterparts. Moreover, raster angle significantly influenced FDM biocomposite properties, enhancing the tensile strength and modulus of untreated WF and cellulose fibers at 0°. Although FDM did not produce alkalized WF samples, epoxy impregnation emerged as a promising method for enhancing PLA/WF composite mechanical properties in the IM process, offering valuable insights for composite material development., (© 2024 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

The rapid advancement of additive manufacturing (AM) technologies has provided new avenues for creating three-dimensional (3D) parts with intricate geometries. Fused Deposition Modeling (FDM) is a prominent technology in this domain, involving the layer-by-layer fabrication of objects by extruding a filament comprising a blend of polymer and metal powder. This study focuses on the FDM process using a filament of Copper-Polylactic Acid (Cu-PLA) composite, which capitalizes on the advantageous properties of copper (high electrical and thermal conductivity, corrosion resistance) combined with the easily processable thermoplastic PLA material. The research delves into the impact of FDM process parameters, specifically, infill percentage (IP), infill pattern (P), and layer thickness (LT) on the maximum failure load (N), percentage of elongation at break, and weight of Cu-PLA composite filament-based parts. The study employs the response surface method (RSM) with Design-Expert V11 software. The selected parameters include infill percentage at five levels (10, 20, 30, 40, and 50%), fill patterns at five levels (Grid, Triangle, Tri-Hexagonal, Cubic-Subdivision, and Lines), and layer thickness at five levels (0.1, 0.2, 0.3, 0.4, and 0.5 mm). Also, the optimal factor values were obtained. The findings highlight that layer thickness and infill percentage significantly influence the weight of the samples, with an observed increase as these parameters are raised. Additionally, an increase in layer thickness and infill percentage corresponds to a higher maximum failure load in the specimens. The peak maximum failure load (230 N) is achieved at a 0.5 mm layer thickness and Tri-Hexagonal pattern. As the infill percentage changes from 10% to 50%, the percentage of elongation at break decreases. The maximum percentage of elongation at break is attained with a 20% infill percentage, 0.2 mm layer thickness, and 0.5 Cubic-Subdivision pattern. Using a multi-objective response optimization, the layer thickness of 0.152 mm, an infill percentage of 32.909%, and a Grid infill pattern was found to be the best configuration.

Additive manufacturing (AM) is not necessarily a new process but an advanced method for manufacturing complex three-dimensional (3D) parts. Among the several advantages of AM are the affordable cost, capability of building objects with complex structures for small-batch production, and raw material versatility. There are several sub-categories of AM, among which is fused filament fabrication (FFF), also commonly known as fused deposition modeling (FDM). FFF has been one of the most widely used additive manufacturing techniques due to its cost-efficiency, simplicity, and widespread availability. The FFF process is mainly used to create 3D parts made of thermoplastic polymers, and complex physical phenomena such as melt flow, heat transfer, solidification, crystallization, etc. are involved in the FFF process. Different techniques have been developed and employed to analyze these phenomena, including experimental, analytical, numerical, and finite element analysis (FEA). This study specifically aims to provide a comprehensive review of the developed numerical models and simulation tools used to analyze melt flow behavior, heat transfer, crystallization and solidification kinetics, structural analysis, and the material characterization of polymeric components in the FFF process. The strengths and weaknesses of these numerical models are discussed, simplifications and assumptions are highlighted, and an outlook on future work in the numerical modeling and FE simulation of FFF is provided., Competing Interests: The authors declare no conflict of interest.

The article presents the results of tribological research of sample models manufactured using three separate 3D printing technologies: selective laser sintering-SLS, photo-curing of liquid polymer resins-PolyJet Matrix (PJM) and fused deposition modeling-FDM. The impact of process parameters (printing direction, layer thickness, and energy density for SLS) on tribological properties was assessed through linear wear and coefficient of friction. The research was carried out to assess the possibility of using 3D printing for the quick manufacturing of casting models, which has a significant impact on shortening the time of implementation for mass production of the casting process. The research results proved the possibility of controlling the technological process in a manner allowing to produce models with controlled properties, including tribological parameters. In addition, the results for three additive technologies and different materials were compared by using the same friction parameters., (Copyright 2023, Mary Ann Liebert, Inc., publishers.)

Polyetheretherketone is a promising material for implants due to its good mechanical properties and excellent biocompatibility. Its accessibility to a wide range of applications is facilitated by the ability to process it with an easy-to-use manufacturing process such as fused filament fabrication. The elimination of disadvantages associated with the manufacturing process, such as a poor surface quality, is a main challenge to deal with. As part of the mass finishing process, centrifugal disc finishing has demonstrated good results in surface optimization, making it a promising candidate for the post-processing of additively manufactured parts. The objective of this study is to identify the key parameters of the centrifugal disc finishing process on the waviness of additively manufactured PEEK specimens, which has not been investigated previously. The waviness of the specimen was investigated by means of confocal laser scanning microscopy (CLSM), while weight loss was additionally tracked. Six parameters were investigated: type, amount and speed of media, use of compound, amount of water and time. Type of media, time and speed were found to significantly influence waviness reduction and weight loss. Surface electron microscopy images demonstrated the additional effects of deburring and corner rounding. Results on previous studies with specimens made of metal showed similar results. Further investigation is required to optimize waviness reduction and polish parts in a second post-processing step.

Additive manufacturing presents promising potential as a sustainable processing technology, notably through integrating post-consumer recycled polymers into production. This study investigated the recycling of high-density polyethylene (rHDPE) into 3D printing filament, achieved by the following optimal extrusion parameters: 180 °C temperature, 7 rpm speed, and 10% glass powder addition. The properties of the developed rHDPE filament were compared with those of commonly used FDM filaments such as acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) to benchmark the performance of rHDPE against well-established materials in the 3D printing industry, providing a practical perspective for potential users. The resulting filament boasted an average tensile strength of 25.52 MPa, slightly exceeding ABS (25.41 MPa) and comparable to PLA (28.55 MPa). Despite diameter fluctuations, the filament proved usable in 3D printing. Mechanical tests compared the rHPDE filament 3D printed objects with ABS and PLA, showing lower strength but exceptional ductility and flexibility, along with superior sound absorption. A life cycle analysis underscored the sustainability advantages of rHDPE, reducing environmental impact compared to conventional disposal methods. While rHDPE falls behind in mechanical strength against virgin filaments, its unique attributes and sustainability position it as a valuable option for 3D printing, showcasing recycled materials' potential in sustainable innovation.

The creation of products with personalized or innovative features in the pharmaceutical sector by using innovative technologies such as three-dimensional (3D) printing is particularly noteworthy, especially in the realm of compounding pharmacies. In this work, 3D printed capsule devices (CDs) with different wall thicknesses (0.2, 0.3, 0.4, 0.6, and 0.9 mm) and sizes were designed and successfully fabricated varying printing parameters such as extrusion temperature, printing speed, material flow percent, and nozzle diameter. The physicochemical, pharmaceutical, and biopharmaceutical performance of these CDs was evaluated with the aim of achieving an immediate drug release profile comparable to hard gelatin capsules (HGC) for use in magistral compounding. It was observed that the disintegration time of the CDs increased with wall thickness, which correlated with a slower drug release rate. CDs with configurations presenting 0.4 mm wall thickness and sizes comparable to HGC n° 0, 1, and 2 demonstrated satisfactory weight uniformity, short disintegration times, and immediate drug release, indicating their potential as effective devices in future compounding pharmacy applications. In addition, a modified Weibull-type model was proposed that incorporates wall thickness as a new variable in predicting dissolution profiles. This model improves the process of selecting a specific wall thickness to achieve the desired dissolution rate within a specified time frame.

The honeycomb structure is a topological structure with excellent performance that stems from the properties of the basic units of the structure. Different structural features of basic units may lead to different mechanical characteristics in the whole part. In this study, a novel hexagonal cell body topology structure (NH) was designed and manufactured by the fused deposition modeling (FDM) technique to explore the effects on mechanical properties. The tensile and impact performance of the NH structure were compared with the regular hexagonal honeycomb structure (HH), and the influence of different unit single-cell sizes on the impact performance of the NH structure was investigated. The force transmission of the basic units of the NH structure was revealed through finite element analysis. The results indicate that both the tensile and impact performances of the NH structure have been improved compared to the HH structure. The improvement is due to the better force transmission capability of the basic units of the NH structure, leading to a more uniform stress distribution. Moreover, excessively large or small single-cell sizes of the NH structure will reduce the overall structure's impact resistance. The overall structure achieves optimal impact resistance when the single-cell size is around 1.2 mm.

This systematic review interrogates the literature to understand what is known about the environmental sustainability of fused filament fabrication, FFF (also known as fused deposition modeling, FDM), based on life cycle assessment (LCA) results. Since substantial energy demand is systematically addressed as one of the main reasons for ecological damage in FFF, mitigation strategies are often based on reducing the printing time (for example, adopting thicker layers) or the embodied energy per part (e.g., by nesting, which means by printing multiple parts in the same job). A key parameter is the infill degree, which can be adjusted to the application requirements while saving printing time/energy and feedstock material. The adoption of electricity from renewable resources is also expected to boost the sustainability of distributed manufacturing through FFF. Meanwhile, bio-based and recycled materials are being investigated as less impactful alternatives to conventional fossil fuel-based thermoplastic filaments.

The fundamental function of an optimal cervical pillow is to provide sufficient support to maintain normal spinal alignment and minimize biological stress on the contact surface throughout sleep. The recent advancements in cervical pillows have mainly focused on the subjective and objective evaluations of support comfort, as well as the relationship between pillow height and cervical vertebrae posture. However, only a few studies have addressed shape design guidelines and mechanical performances of the pillows themselves. In this study, a two-sectional contour cervical pillow comprising an arc and a Bezier curve is designed to support the head and neck. The design of the arc-shaped neck section incorporates the Cobb's angle and Borden value from healthy individuals to reflect the consistency of normal cervical anatomical features. The Bezier curve-based head section takes the head length and neck depth into account as significant individual differences. Static analysis and lattice optimization are performed in ANSYS Workbench to develop a variable-density cellular structure, aimed at improving air permeability and reducing the risk of pressure ulcers associated with the cervical pillow. The rapid prototyping technique fused deposition modeling (FDM) and thermoplastic material polylactic acid (PLA) are employed for fabricating different cellular structures. The results demonstrate that the neck section experiences less stress and greater deformation in comparison to the head section, indicating good comfort and support provided by the designed cervical pillow. Additionally, the compressive, bending, and cushion properties of the 3D-printed cervical pillow with variable-density cellular structure are experimentally validated, further confirming its effectiveness.

Short carbon fiber (SCF) reinforced polymer composites are expected to possess outstanding biotribological and mechanical properties in certain direction, while the non-oriented SCF weakens its reinforcing effect in the matrix. In this work, high-oriented SCF was achieved during nozzle extrusion, and then SCF reinforced polyether-ether-ketone (PEEK) composites were fabricated by fused deposition modeling (FDM). The concrete orientation process of SCF was theoretically simulated, and significant shear stress difference was generated at both ends of SCF. As a result, the SCF was distributed in the matrix in a hierarchical structure, containing surface layer I, II and core layer. Moreover, the SCF was oriented highly along the printing direction and demonstrated a more competitive orientation distribution compared to other studies. The SCF/PEEK composites showed a considerable improvement in wear resistance by 44 % due to self-lubricating and load-bearing capability of SCF. Besides, it demonstrated enhancements in Brinell hardness, compressive and impact strength by 48.52 %, 16.42 % and 53.64 %, respectively. In addition, SCF/PEEK composites also showed good cytocompatibility. The findings gained herein are useful for developing the high-oriented SCF reinforced polymer composites with superior biotribological and mechanical properties for artificial joints., Competing Interests: Declaration of competing interest With submitting the manuscript, the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This paper investigates the effect of nozzle temperature, from 180 to 260 °C, on properties of polylactic acid (PLA) samples manufactured by fused deposition modeling (FDM) technology. The main objective of this research is to determinate an optimum nozzle temperature relative to tensile, flexural and compressive properties of printed specimens. After manufacturing, the samples exhibit an amorphous structure, without crystallization effects, independently of the fabrication temperature. In order to determine the influence of printing temperature on mechanical properties, uniaxial tensile, three-point flexural and compression strength tests were carried out. The obtained results suggest that a relative low printing temperature could reduce the material flow and decrease the density of the final prototype, with a negative effect on both the quality and the mechanical properties of the pieces. If temperature increases up to 260 °C, an excess of material can be deposited, but with no significant negative effect on mechanical parameters. There is an optimum nozzle temperature interval, depending on the considered piece and test, for which mechanical values can be optimized. Taking into account all tests, a recommended extruder temperature interval may be identified as 220-240 °C. This range encompasses all mechanical parameters, avoiding the highest temperature where an excess of material was observed. For this printing temperature interval, no significant mechanical variations were appreciated, which corresponds to a stable behavior of the manufactured specimens.

Traditional fabrication methods for creating flexible magnetoelectric sensors are often laborious and challenging when it comes to personalization. This article employs fused deposition modeling 3D printing technology to produce flexible multifunctional sensors. (0-3) type composite filaments were prepared using polyvinylidene fluoride and cobalt ferrite (CoFe 2 O 4 , abbreviated as CFO). These filaments can be printed into various shapes, exhibiting good mechanical and electrical properties. Crucial parameters, such as different component ratios and CFO particle sizes, were analyzed. This study can serve as a valuable reference for the future development of personalized wearable sensors., (Copyright 2023, Mary Ann Liebert, Inc., publishers.)

This study focuses on the combination of three-dimensional printing (3DP) and amorphous solid dispersion (ASD) technologies for the manufacturing of gastroretentive floating tablets. Employing hot melt extrusion (HME) and fused deposition modeling (FDM), the study investigates the development of drug-loaded filaments and 3D printed (3DP) tablets containing felodipine as model drug and hydroxypropyl methylcellulose (HPMC) as the polymeric carrier. Prior to fabrication, solubility parameter estimation and molecular dynamics simulations were applied to predict drug-polymer interactions, which are crucial for ASD formation. Physical bulk and surface characterization complemented the quality control of both drug-loaded filaments and 3DP tablets. The analysis confirmed a successful amorphous dispersion of felodipine within the polymeric matrix. Furthermore, the low infill percentage and enclosed design of the 3DP tablet allowed for obtaining low-density systems. This structure resulted in buoyancy during the entire drug release process until a complete dissolution of the 3DP tablets (more than 8 h) was attained. The particular design made it possible for a single polymer to achieve a zero-order controlled release of the drug, which is considered the ideal kinetics for a gastroretentive system. Accordingly, this study can be seen as an advancement in ASD formulation for 3DP technology within pharmaceutics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Additive manufacturing (AM) has arisen as a transformative technology for manufacturing complex geometries with enhanced mechanical properties, particularly in the realm of continuous fiber-reinforced polymer composites (CFRPCs). Among various AM techniques, fused deposition modeling (FDM) stands out as a promising method for the fabrication of CFRPCs due to its versatility, ease of use, flexibility, and cost-effectiveness. Several research papers on the AM of CFRPs via FDM were summarized and therefore this review paper provides a critical examination of the process-printing parameters influencing the AM process, with a focus on their impact on mechanical properties. This review covers details of factors such as fiber orientation, layer thickness, nozzle diameter, fiber volume fraction, printing temperature, and infill design, extracted from the existing literature. Through a visual representation of the process parameters (printing and material) and properties (mechanical, physical, and thermal), this paper aims to separate out the optimal processing parameters that have been inferred from various research studies. Furthermore, this analysis critically evaluates the current state-of-the-art research, highlighting advancements, applications, filament production methods, challenges, and opportunities for further development in this field. In comparison to short fibers, continuous fiber filaments can render better strength; however, delamination issues persist. Various parameters affect the printing process differently, resulting in several limitations that need to be addressed. Signifying the relationship between printing parameters and mechanical properties is vital for optimizing CFRPC fabrication via FDM, enabling the realization of lightweight, high-strength components for various industrial applications.

Fused Deposition Modeling (FDM) is a well-established manufacturing method for producing both prototype and functional components. This study investigates the mechanical properties of FDM components by material and process-related influencing variables. Tensile tests were conducted on seven different materials in their raw filament form, two of which were fiber-reinforced, to analyze their material-related influence. To cover a wide range from standard to advanced materials relevant for load-carrying components as well as their respective variations, polylactic acid (PLA), 30% wood-fiber-reinforced PLA, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), a blend of ABS and PC, Nylon, and 30% glass-fiber-reinforced Nylon were selected. The process-related influencing variables were studied using the following process parameters: layer thickness, nozzle diameter, build orientation, nozzle temperature, infill density and pattern, and raster angle. The first test series revealed that the addition of wood fibers significantly worsened the mechanical behavior of PLA due to the lack of fiber bonding to the matrix and significant pore formation. The polymer blend of ABS and PC only showed improvements in stiffness. Significant strength and stiffness improvements were found by embedding glass fibers in Nylon, despite partially poor fiber-matrix bonding. The materials with the best properties were selected for the process parameter analysis. When examining the impact of layer thickness on part strength, a clear correlation was evident. Smaller layer thicknesses resulted in higher strength, while stiffness did not appear to be affected. Conversely, larger nozzle diameters and lower nozzle temperatures only positively impacted stiffness, with little effect on strength. The part orientation did alter the fracture behavior of the test specimens. Although an on-edge orientation resulted in higher stiffness, it failed at lower stresses. Higher infill densities and infill patterns aligned with the load direction led to the best mechanical results. The raster angle had a significant impact on the behavior of the printed bodies. An alternating raster angle resulted in lower strengths and stiffness compared to a unidirectional raster angle. However, it also caused significant stretching due to the rotation of the beads.

The present study aims to investigate the potential of the 3D printing technique to design gastroretentive floating tablets (GFTs) for modifying the drug release profile of an immediate-release tablet. A 3D-printed floating shell enclosing a captopril tablet was designed having varying number of drug-release windows. The impact of geometrical changes in the design of delivery system and thermal cross-linking of polymers were evaluated to observe the influence on floating ability and drug release. Water uptake, water insolubilization, Differential Scanning Calorimetry (DSC), and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) were performed to assess the degree of thermal cross-linking of polyvinyl alcohol (PVA) filament. The 3D-printed GFT9 was considered the optimized gastric floating tablet that exhibited >12 h of total floating time with zero floating lag time and successfully accomplished modified-drug release by exhibiting >80% of drug release in 8 h. The zero-order release model, with an r 2 value of 0.9923, best fitted the drug release kinetic data of the GFT9, which followed a super case II drug transport mechanism with an n value of 0.95. The optimized gastric floating device (GFT9) also exhibited the highest MDT values (238.55), representing slow drug release from the system due to thermal crosslinking and the presence of a single drug-releasing window in the device.

Purpose: This study outlined the prevalent use of brachytherapy in skin cancers, such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The importance of customized applicator fabrication for optimal treatment delivery was highlighted, focusing on adaptable devices tailored to individual patient anatomy, often facilitated by 3D printing technology. The purpose of this work was to investigate the association of medical science and 3D printing in customized applicator fabrication for brachytherapy, leveraging the advancements in fabrication techniques to enhance treatment precision and patient outcomes., Material and Methods: The study enrolled five patients with tumor lesions unsuitable for surgical intervention, situated across various anatomical locations, such as earlobe, temple, hand, and cheek. Customized applicators were fabricated via 3D printing (fused deposition modeling) for each patient, followed by radiotherapy protocol delivering a total dose of 51 Gy in 17 fractions. Patient assessments during and post-radiotherapy were done by radiation oncologist using RTOG scale as well as dermatological evaluations with dermatoscopy and reflectance confocal microscopy. Methodologically, applicators were 3D-printed using fused deposition modeling technology. Printing parameters were optimized in Prusa Slicer software, ensuring precise control in printout shape correlated with treatment efficacy., Results: This study examined the therapeutic outcomes of brachytherapy in five patients with inoperable skin cancer lesions. Utilizing customized 3D-printed applicators, the patients underwent brachytherapy regimen delivering a cumulative dose of 51 Gy in 17 fractions. The evaluation with RTOG scale revealed varied treatment responses, with complete remission achieved in all cases. Reflectance confocal microscopy showed post-treatment normalization of epidermal morphology and notable scar formation. Optical profilometry demonstrated consistent micro-structures on the applicator surfaces, without compromising treatment efficacy. These findings indicated the potential of 3D-printed applicators in optimizing brachytherapy outcomes in skin cancer management., Conclusions: Our study demonstrates the effectiveness of 3D-printed applicators in treating inoperable skin cancer lesions with high precision. In personalized fabrication, optimal conformity with anatomical features was achieved, resulting in complete remission in all patients. This approach minimizes treatment-related side effects and enhances overall patient outcomes, suggesting a promising future for 3D printing technology in skin cancer treatment applications. Further research and clinical validation are needed to establish 3D printing as a standard practice in skin cancer treatment., Competing Interests: The authors report no conflict of interest., (Copyright © 2024 Termedia.)

Anti-counterfeiting in 3D printing has gained significant attention, however, current approaches often fall short of fully capitalizing on the inherent advantages of personalized manufacturing with this technology. Herein, we propose an embedded anti-counterfeiting scheme for additive manufacturing, accompanied by a novel fluorescent encrypted quick response (QR) method. This approach involves the development of a 3D printing filament utilizing poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) bio-composites as the primary filament matrix, with varying quantities of Chlorella powder incorporated. The resulting filament has a good thermal stability near 200 °C and exhibits a distinctive red fluorescence under ultraviolet light, with the emission peak at 677 nm when excited by 415 nm blue light. Fluorescence imaging analysis confirms that the red fluorescence in 3D printed devices containing Chlorella is a result of the chlorophyll and its derivatives fluorescence effect. The fluorescent encrypted QR codes are inconspicuous in daylight but become easily discernible under ultraviolet light. In the cases of recognizable QR codes, the ∆Eab* values all exceed 35, and the L C /L B values deviate significantly from 1. This research delves into the fluorescence characteristics of Chlorella and highlights its applicability in 3D printing, specifically within the realm of product anti-counterfeiting, presenting a groundbreaking approach., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Fused Deposition Modelling (FDM) is one of the layer-based technologies that fall under the umbrella term "Additive Manufacturing", where the desired part is created through the successive layer-by-layer addition process with high accuracy using computer-aided design data. Additive manufacturing technology, or as it is commonly known, 3D (three-dimensional) printing, is a rapidly growing sector of manufacturing that is incorporated in automotive, aerospace, biomedical, and many other fields. This work explores the impact of the Additive Manufacturing process on the mechanical proprieties of the fabricated part. To conduct this study, the 3D printed tensile specimens are designed according to the ASTM D638 standards and printed from a digital template file using the FDM 3D printer Raise3D N2. The material chosen for this 3D printing parameter optimization is Polylactic acid (PLA). The FDM process parameters that were studied in this work are the infill pattern, the infill density, and the infill cell orientation. These factors' effects on the tensile behavior of printed parts were analyzed by the design of experiments method, using the statistical software MINITAB2020.