Additive Printing Research Articles

The use of additive 3D printing technologies in the training of vertebrologists

Additive technologies (3D printing) can be used in teaching surgical treatment of diseases and injuries of the spinal column due to the ability to produce both standard anatomical models and models based on patient imaging data. The presented opportunities allow you to practice and maintain manual surgical skills, choose the most appropriate surgical treatment tactics at the preoperative stage, taking into account the individual anatomical characteristics of the patients and the characteristics of the pathological process.

3D printing adoption in NHS trusts within the United Kingdom

Additive manufacturing and 3D printing is being widely adopted by the medical industry. This study provides a comprehensive overview of the current state of 3D printing technology in NHS trusts across the UK. Data was collected through a survey using the freedom of information act. The survey revealed that 53 NHS trusts (∼25 %) across the UK are utilising the technology, with a diverse range of strategies and applications. The most common application was the creation of guides and models, used for pre-operative planning, intraoperative guidance, and educational purposes. The study also highlights the regulatory and ethical considerations involved in 3D printing in healthcare. The findings indicate that there are no 3D printing specific standards or guidelines being followed for medical devices and therefore underscores the need for clear and consistent regulatory guidelines to be established. As the 3D printing technology continues to advance, its applications in healthcare are expected to expand rapidly, warranting further research into its impact on patient outcomes and healthcare costs.

A framework for integrating additive manufacturing into engineering education: perspectives of students and educators

ABSTRACT Additive manufacturing (AM) and 3D printing (3DP) offer unique opportunities for experiential learning and practical application in engineering education. In developed countries, AM is integrated into engineering education to train mechanical engineers. However, existing research has not investigated the integration of AM and 3DP into higher education in developing countries. Semi-structured interviews were conducted with students and educators from mechanical engineering programmes in Vietnam to examine AM usage in engineering education. Our study revealed that no curricula or policies to integrate AM into classrooms exist in the participating institutions. Engineering schools are attempting to introduce 3DP to students through short courses, but educators have inadequate training. The lack of consistent communication among institutions has hindered the growth of 3DP education. Therefore, to meet the standards of Industry 4.0, it is crucial to have policies and funding in place to promote AM growth among first-year engineering students.

Towards a Sustainable Laser Powder Bed Fusion Process via the Characterisation of Additively Manufactured Nitinol Parts

Is additive manufacturing (AM) a sustainable process? Can the process be optimised to produce sustainable AM parts and production techniques? Additive manufacturing offers the production of parts made of different types of materials in addition to the complex geometry that is difficult or impossible to produce by using the traditional subtractive methods. This study is focused on the optimisation of laser powder bed fusion (L-PBF), one of the most common technologies used in additive manufacturing and 3D printing. This research was carried out by modulating the build layer thickness of the deposited metal powder and the input volumetric energy density. The aim of the proposed strategy is to save the build time by maximizing the applied layer thickness of nitinol powder while retrieving the different AM part properties. The saving in the process time has a direct effect on the total cost of the produced part as a result of several components like electric energy, inert gas consumption, and labour. Nickel-rich nitinol (52.39 Ni at.%) was selected for investigation in this study due to its extremely high superplastic and shape memory properties in addition to the wide application in various industries like aerospace, biomedical, and automotive. The results obtained show that significant energy and material consumption can be found by producing near full dens AM parts with limited or no alteration in chemical and mechanical properties.

The Scratch Resistance of a Plasma-Assisted DUPLEX-Treated 17-4 Precipitation-Hardened Stainless Steel Additively Manufactured by Laser Powder Bed Fusion

The Scratch Resistance of a Plasma-Assisted DUPLEX-Treated 17-4 Precipitation-Hardened Stainless Steel Additively Manufactured by Laser Powder Bed Fusion

Design, In Vitro Evaluation and In Vivo Biocompatibility of Additive Manufacturing Three-Dimensional Printing of β beta-Tricalcium Phosphate Scaffolds for Bone Regeneration

The reconstruction of bone deficiencies remains a challenge due to the limitations of autologous bone grafting. The objective of this study is to evaluate the bone regeneration efficacy of additive manufacturing of tricalcium phosphate (TCP) implants using lithography-based ceramic manufacturing (LCM). LCM uses LithaBone TCP 300 slurry for 3D printing, producing cylindrical scaffolds. Four models of internal scaffold geometry were developed and compared. The in vitro studies included cell culture, differentiation, seeding, morphological studies and detection of early osteogenesis. The in vivo studies involved 42 Wistar rats divided into four groups (control, membrane, scaffold (TCP) and membrane with TCP). In each animal, unilateral right mandibular defects with a total thickness of 5 mm were surgically performed. The animals were sacrificed 3 and 6 months after surgery. Bone neoformation was evaluated by conventional histology, radiology, and micro-CT. Model A (spheres with intersecting and aligned arrays) showed higher penetration and interconnection. Histological and radiological analysis by micro-CT revealed increased bone formation in the grafted groups, especially when combined with a membrane. Our innovative 3D printing technology, combined with precise scaffold design and efficient cleaning, shows potential for bone regeneration. However, further refinement of the technique and long-term clinical studies are crucial to establish the safety and efficacy of these advanced 3D printed scaffolds in human patients.

Empowering Rehabilitation: Design and Structural Analysis of a Low-Cost 3D-Printed Smart Orthosis.

Three-dimensional (3D) printing of polymer materials encompasses a wide range of applications and innovations. Polymer-based 3D printing, also known as additive manufacturing, has gained significant attention due to its versatility, cost-effectiveness, and potential to revolutionize various industries. The current paper focuses on obtaining a durable low-cost rehabilitation knee orthosis. Researchers propose that the entire structure should be obtained using modern equipment within the additive manufacturing domain-3D printing. The researchers focus on determining, through a 3D analysis of the entire 3D model assembly, which parts present a high degree of stress when a kinematic simulation is developed. The entire 3D model of the orthosis starts based on the result obtained from a 3D scanning of the knee joint of a patient, providing a precise fixation, and allowing for direct personalization. Based on the results and identification of the critical parts, there will be used different materials and a combination of 3D printing strategies to validate the physical model of the entire orthosis. For the manufacturing process, the researchers use two types of low-cost fused filament fabrication (FFF), which are easy to find on the worldwide market. The motivation for manufacturing the entire assembly using 3D printing techniques is the short time in which complex shapes can be obtained, which is relevant for the present study. The main purpose of the present research is to advance orthotic technology by developing an innovative knee brace made of 3D-printed polymers that are designed to be lightweight, easy-to-use, and provide comfort and functionality to patients during the rehabilitation process.

Parameter Tuning for Sustainable 3D Printing (3DP) of Clay Structures

Due to high carbon emissions, traditional construction methods are often costly, resource-intensive, and environmentally harmful. This study investigates the potential of additive manufacturing (AM) or 3D printing (3DP) using earthen clay as a sustainable alternative for building structures. Despite its promising benefits, challenges such as water/clay ratio, nozzle clogging, and temperature variations hinder widespread adoption. Employing the design of experiment (DOE) approach, this research systematically optimizes 3DP parameters, including nozzle diameter, layer height, infill percentage, and printing speed, using commercial earthen clay. Chemical compositions are analyzed using X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectroscopy (EDS). Quantitative analysis compares measured dimensions of 3DP structures to assess dimensional accuracy, while buildability assessments explore structural integrity. Results indicate that lower layer heights generally enhance dimensional accuracy, with larger nozzle diameters enabling faster printing speeds. ANOVA analysis reveals significant relationships between printing parameters and dimensional outcomes, emphasizing the importance of 3DP process parameters selection. Optimal printing parameters lead to high-quality prints, although with limitations in scalability. This research contributes valuable insights for stakeholders seeking sustainable 3DP practices in construction, paving the way for more environmentally friendly and cost-effective building solutions.

Additive Manufacturing: A Comprehensive Review.

Additive manufacturing has revolutionized manufacturing across a spectrum of industries by enabling the production of complex geometries with unparalleled customization and reduced waste. Beginning as a rapid prototyping tool, additive manufacturing has matured into a comprehensive manufacturing solution, embracing a wide range of materials, such as polymers, metals, ceramics, and composites. This paper delves into the workflow of additive manufacturing, encompassing design, modeling, slicing, printing, and post-processing. Various additive manufacturing technologies are explored, including material extrusion, VAT polymerization, material jetting, binder jetting, selective laser sintering, selective laser melting, direct metal laser sintering, electron beam melting, multi-jet fusion, direct energy deposition, carbon fiber reinforced, laminated object manufacturing, and more, discussing their principles, advantages, disadvantages, material compatibilities, applications, and developing trends. Additionally, the future of additive manufacturing is projected, highlighting potential advancements in 3D bioprinting, 3D food printing, large-scale 3D printing, 4D printing, and AI-based additive manufacturing. This comprehensive survey aims to underscore the transformative impact of additive manufacturing on global manufacturing, emphasizing ongoing challenges and the promising horizon of innovations that could further elevate its role in the manufacturing revolution.

Optimization of Environment-Friendly and Sustainable Polylactic Acid (PLA)-Constructed Triply Periodic Minimal Surface (TPMS)-Based Gyroid Structures.

The demand for robust yet lightweight materials has exponentially increased in several engineering applications. Additive manufacturing and 3D printing technology have the ability to meet this demand at a fraction of the cost compared with traditional manufacturing techniques. By using the fused deposition modeling (FDM) or fused filament fabrication (FFF) technique, objects can be 3D-printed with complex designs and patterns using cost-effective, biodegradable, and sustainable thermoplastic polymer filaments such as polylactic acid (PLA). This study aims to provide results to guide users in selecting the optimal printing and testing parameters for additively manufactured/3D-printed components. This study was designed using the Taguchi method and grey relational analysis. Compressive test results on nine similarly patterned samples suggest that cuboid gyroid-structured samples perform the best under compression and retain more mechanical strength than the other tested triply periodic minimal surface (TPMS) structures. A printing speed of 40 mm/s, relative density of 60%, and cell size of 3.17 mm were the best choice of input parameters within the tested ranges to provide the optimal performance of a sample that experiences greater force or energy to compress until failure. The ninth experiment on the above-mentioned conditions improved the yield strength by 16.9%, the compression modulus by 34.8%, and energy absorption by 29.5% when compared with the second-best performance, which was obtained in the third experiment.

Factors affecting interface bonding in multi-material additive manufacturing

Additive manufacturing or 3D printing is the process of depositing material layer-by-layer to create 3-dimensional products. When creating 3D-printed products from two or more materials, multi-material additive manufacturing processes are used which eliminate the need for assembly operations. Fused filament fabrication multi-material additive manufacturing permits the production of a single printed item employing multiple materials in fused filament fabrication. This work studied the factors affecting fused filament fabrication multi-material additive manufacturing, by reviewing existing works, designing part(s), conducting design of experiments, and carrying out parts’ performance test. An E3D multi-material filament 3D printer was utilised throughout this study. The chosen polymer combination was polycarbonate (PC) and poly(methyl methacrylate) (PMMA), whilst the design and testing of the multi-material parts was limited to lap-shear testing. Results showed that the interface bonding of the PMMA/PC (PMMA printed first and followed by PC) specimens was stronger than the one of the PC/PMMA specimens. Furthermore, to investigate the effect of the contact or overlapping area on the interface bonding strength, PMMA/PC specimens with varying dimensions were designed, printed, and tested. When the contact area was reduced, a strong interface bonding between the PMMA and PC layers was still maintained.

Empirical BRDF model for goniochromatic materials and soft proofing with reflective inks.

The commonly used analytic bidirectional reflectance distribution functions (BRDFs) do not model goniochromatism, that is, angle-dependent material color. The material color is usually defined by a diffuse reflectance spectrum or RGB vector and a specular part based on a spectral complex index of refraction. Extension of the commonly used BRDFs based on wave theory can help model goniochromatism, but this comes at the cost of significant added model complexity. We measured the goniochromatism of structual color pigments used for additive color printing and found that we can fit the observed spectral angular dependence of the bidirectional reflectance using a simple modification of the standard microfacet BRDF model. All we need to describe the goniochromatism is an empirically-based spectral parameter, which we use in our model together with a specular reflectance spectrum instead of the spectral complex index of refraction. We demonstrate the ability of our model to fit the measured reflectance of red, green, and blue commercial structural color pigments. Our BRDF model enables straightforward implementation of a shader for interactive preview of 3D objects with printed spatially and angularly varying texture.

Tailoring the Mass Density of 3D Printing Materials for Accurate X-ray Imaging Simulation by Controlled Underfilling for Radiographic Phantoms.

Additive manufacturing and 3D printing allow for the design and rapid production of radiographic phantoms for X-ray imaging, including CT. These are used for numerous purposes, such as patient simulation, optimization of imaging procedures and dose levels, system evaluation and quality assurance. However, standard 3D printing polymers do not mimic X-ray attenuation properties of tissues like soft, adipose, lung or bone tissue, and standard materials like liquid water. The mass density of printing polymers-especially important in CT-is often inappropriate, i.e., mostly too high. Different methods can be applied to reduce mass density. This work examines reducing density by controlled underfilling either realized by using 3D printing materials expanded through foaming during heating in the printing process, or reducing polymer flow to introduce microscopic air-filled voids. The achievable density reduction depends on the base polymer used. When using foaming materials, density is controlled by the extrusion temperature, and ranges from 33 to 47% of the base polymer used, corresponding to a range of -650 to -394 HU in CT with 120 kV. Standard filaments (Nylon, modified PLA and modified ABS) allowed density reductions by 20 to 25%, covering HU values in CT from -260 to 77 (Nylon), -230 to -20 (ABS) and -81 to 143 (PLA). A standard chalk-filled PLA filament allowed reproduction of bone tissue in a wide range of bone mineral content resulting in CT numbers from 57 to 460 HU. Controlled underfilling allowed the production of radiographic phantom materials with continuously adjustable attenuation in a limited but appropriate range, allowing for the reproduction of X-ray attenuation properties of water, adipose, soft, lung, and bone tissue in an accurate, predictable and reproducible manner.

Designing Centrifugal Membrane Filters with uniform-pressure for UF/NF/RO separations

A novel Ortho-Centrifugal Membrane Filter (O-CMF) was designed and assessed to tackle common issues in conventional laboratory centrifugal membrane filters, e.g. non-uniform transmembrane pressure and concentration polarization, and to ease membrane replacement. The O-CMF, manufactured by additive 3D printing in acrylonitrile butadiene styrene, with membrane area of 0.95 cm2, was designed to process a maximum liquid sample of 9 mL. It was tested with nanofiltration of aqueous solutions of NaCl, MgSO4, and lactose (concentrations of 1–20 g/L) at transmembrane pressures of 6–24 bar. Complementary Computational Fluid Dynamics (CFD) simulations, employing a custom solver from the open-source OpenFOAM-2306 c++ toolbox, were also run to seek insight of the O-CMF main features.The permeation experiments displayed minimal impact of concentration polarization. CFD simulations showed that concentration polarization is nearly uniform and that concentrate chamber is homogenized by centrifugal convection. The CFD permeate flux predictions, based on the osmotic pressure model, closely matched experimental data, and a correlation for predicting concentration polarization was also developed.The O-CMF device represents a substantial breakthrough in the technology of centrifugal membrane filters, consistently maintaining uniform transmembrane pressure and effectively minimizing concentration polarization. The device was evaluated using nanofiltration, but its pressure range is versatile enough to cover conditions suitable for both ultrafiltration and reverse osmosis operations. This adaptability extends its application across a variety of laboratory experiments, including sample concentration, hydraulic permeability tests, and membrane screening.

Unlocking the Potential of 3D Printing in Modern Manufacturing

The process of producing tangible items by layering on materials according to geometric representations is called digital fabrication technology, sometimes referred to as additive manufacturing or 3D printing. This innovative technique has gained popularity. Numerous industries, including healthcare, automotive, locomotive, and aviation, now make extensive use of the quickly expanding area of 3D printing technology. This page discusses the materials utilized in the production process, provides a summary of the many types of 3D printing technology, and illustrates the extensive variety of uses for them With the potential to create intricate structures and personalized patterns straight from computer-aided design (CAD) models, 3D printing technology is a potent instrument that has the potential to completely alter the face of contemporary production.

Industry 4.0 and Sustainability: a Study on the Applicability of Additive Manufacturing as a Tool for Minimizing Environmental Impacts on Production Processes

Objective: The present research sought to analyze the applicability of additive manufacturing as a tool for minimizing environmental damage in production processes. Methodology: The research was conducted through an integrative literature review. Academic platforms such as SciELO and Google Academic were consulted, using specific keywords related to the theme. Inclusion criteria were established to select complete articles, in Portuguese and Brazilian languages, directly associated with the research theme, published between 2020 and 2024. Results and data analysis: The revised studies emphasize the growing importance of additive manufacturing (AM) and 3D printing technology in transforming production processes towards more sustainable and efficient practices. MA's ability to produce complex parts accurately and personalized, significantly reducing raw material waste through layer-by-layer manufacturing, stands out as a crucial tool to minimize environmental impacts on production. In addition, the integration of MA in the early stages of product development promotes efficiency in production, although more in-depth studies on its environmental and energy impacts are needed. Conclusion: It is therefore concluded that additive manufacturing is an essential tool for more sustainable and innovative practices in the industry, promoting the conservation of natural resources, the reduction of waste and the creation of adaptable and customized solutions. It is therefore up to companies and society to exploit and develop these technologies in search of a more sustainable and competitive future.

Circular closed-loop supply chain network design considering 3D printing and PET bottle waste

AbstractOne of the most critical pillars of Industry 4.0 (I4.0) is Additive Manufacturing (AM) or 3D Printing technology. This transformative technology has garnered substantial attention due to its capacity to streamline processes, save time, and enhance product quality. Simultaneously, environmental concerns are mounting, with the growing accumulation of plastic bottle waste, offering a potential source of recycled material for 3D printing. To thoroughly harness the potential of AM and address the challenge of plastic bottle waste, a robust supply chain network is essential. Such a network not only facilitates the reintegration of plastic bottle waste and 3D printing byproducts into the value chain but also delivers significant environmental, social, and economic benefits, aligning with the tenets of sustainable development and circular economy. To tackle this complex challenge, a Mixed-Integer Linear Programming (MILP) mathematical model is offered to configure a Closed-Loop Supply Chain (CLSC) network with a strong emphasis on circularity. Environmental considerations are integral, and the primary objective is to minimize the overall cost of the network. Three well-known metaheuristics of Simulated Annealing (SA), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO) are employed to treat the problem which are also efficiently adjusted by the Taguchi design technique. The efficacy of our solution methods is appraised across various problem instances. The findings reveal that the developed model, in conjunction with the fine-tuned metaheuristics, successfully optimizes the configuration of the desired circular CLSC network. In conclusion, this research represents a significant step toward the establishment of a circular supply chain that combines the strengths of 3D printing technology and the repurposing of plastic bottle waste. This innovative approach holds promise for not only reducing waste and enhancing sustainability but also fostering economic and social well-being.

Prediction surface roughness of 3D printed parts using genetic algorithm optimized hybrid learning model

The final product of additive manufacturing (AM) or 3D printing critically depends on the surface quality. An experimental study on the 3D printed intake manifold flange using acrylonitrile butadiene styrene (ABS) material was executed by varying the four process parameters. A fused deposition modeling (FDM) based 3D printer was used to fabricate the flanges. The association between the parameters and the surface roughness of printed ABS flanges was investigated. A feed forward neural network (FFNN) model trained on particle swarm optimization (PSO) optimized with a genetic algorithm (GA) was used to estimate the surface roughness. A Box-Behnken design (BBD) with printing parameters at three levels was used, and 25 parts were fabricated. The suggested model demonstrated a coefficient of determination (R2) of 0.9865 on test values, mean of root-mean-square-error (RMSE) of 0.1231 after 500 times training for generalization. And also mean of overfitting factor is 0.7110. This means that the suggested system could generalize. Comparing the results from the suggested model and ANN, the suggested hybrid model outperformed ANN in predicting the surface roughness values with no overfitting. This suggests that GA optimized PSO based FFNN may be a more suitable method for estimating product quality in terms of surface roughness.

Risk assessment and toxicity effects of materials used during additive manufacturing with FDM technology

This paper discusses the potential of additive printing, the risks it poses to users' health (including 3D printer operators) and the effects of chemical substances released during the printing based on the available in vitro and in vivo studies. It was shown that substances emitted during printing with the commonly used acrylonitrile butadiene styrene filament in additive manufacturing might have carcinogenic, hepatotoxic and teratogenic effects, as well as toxic effect on the respiratory system. The latest research on the mechanism of formation of particles and volatile organic compounds during 3D printing, the parameters affecting their potential emission, and trends in reducing these hazards are indicated. The need for the design of more environmentally friendly and less emissive printing materials, as well as strategies for prevention and individual and collective protection measures are emphasized. Users of 3D printers should be familiar with all possible aspects of the threats associated with the printing process. Insufficient data on direct exposure to chemicals and particles released during the use of filaments makes it difficult to build awareness of safe working practices. Of particular concern is the health impact of emitted chemicals and particles from thermally treated materials in one of the most popular technologies for 3D printing, i.e., fused deposition modelling. Exposure of the users to, e.g., plasticizers added to filaments occurs through a variety of routes, by absorption through the skin, by inhalation or ingestion. Available epidemiological data, as well as current experimental works, indicate that such exposure is a high risk of cardiovascular diseases, atherosclerosis in adults, and cardiac problems and metabolic disorders in children. This review, by identifying potential risk factors, may contribute to reducing the health loss of printer users and improving working conditions and safety, especially in enterprises where additive manufacturing technology is used. Med Pr Work Health Saf. 2024;75(2):159-171.

Additive In-Time Manufacturing of Customised Orthoses

Additive manufacturing of plastic components in medical technology enables greater freedom of design when designing patient-specific products, in particular, in production of customised medical products, such as orthoses. In the present contribution, the advantages of a digital process chain are combined, from the 3D scan of the patient to CAD-supported modelling of the corrective form and the orthosis design until the path planning of a printable geometry. The main disadvantages of current additive printing techniques, such as the fused filament fabrication (FFF) process, are high printing times (>12 h) for larger components as well as the low degree of freedom in the 2.5D printing technique that prevent the subsequent application of geometry features to the product. The fast SEAMHex (Screw Extrusion Additive Manufacturing) printing technology with a hexapod kinematic printing bed provides a solution to the mentioned difficulties. Consequently, the high-performance printer has been prepared for the individual requirements of medical technology in terms of materials and geometries. An effective additive manufacturing process has been realised and tested in combination with a digital process chain for orthosis modelling.