3D Printing Materials Research Articles

Solvent-free Acrylate/BCB drop-on-demand (DOD) inkjet dielectric ink for 3D printing

Currently, drop-on-demand (DOD) inkjet-printed dielectric inks used to produce next-generation high-frequency electronic devices fail to meet the requirements of circuit board substrates in terms of thermal, mechanical, and dielectric properties. To address this gap, we synthesized a low-viscosity acrylate monomer featuring an intrinsically low dielectric structure (hexafluorobisphenol A) and multiple cross-linking sites, and a benzocyclobutene monomer with low curing shrinkage and excellent thermomechanical properties. By mixing these monomers with other reactive diluents and verifying them through theoretical calculations and printing, we have developed a range of dielectric inks suitable for inkjet 3D printing. To enhance the overall performance of the cured inks, a sequential UV/thermal curing strategy was employed to form interpenetrating networks (IPNs). The optimal ink formulations met the requirements of circuit board substrates, demonstrating excellent heat resistance (Td5% = 334 °C, Tg = 181 °C), mechanical properties (tensile strength = 85 MPa, elongation at break = 13.5 %), and dielectric properties (Dk = 2.526 and Df = 0.113 at 15 GHz). These formulations meet the performance requirements for circuit board substrates and lead the industry in mechanical and dielectric properties. Furthermore, the feasibility of inkjet printing heterogeneous integrated electronic devices was verified, showing excellent print resolution and continuity of the conductive network. This work provides new insights into the future development of dielectric materials for inkjet 3D printing.

An investigation of prototype development using 3D printer: A digital fabrication approach

Abstract Additive manufacturing (AM) is a widely used technique in several industries for rapid prototyping and layer-by-layer fabrication of a new product. The influence of printer settings and print quality is essential for the performance of products in a variety of applications. The popularity of manufacturing using 3D printing is growing rapidly. In view of this, an investigation is carried out on the 3D printing techniques, their applications, and prototype materials for complex mechanical parts such as an impeller. The present study thoroughly considers the fundamental techniques in 3D printing technology, materials, and recent advancements applied to the current application and accepted trends. The 3D printing technology is advantageous as it accepts a wide range of designs, allows customized manufacturing, minimizes waste, builds intricate structures, and creates prototypes rapidly. Layer height of 0.2 mm, speed of 90 mm/s, and infill density of 80% were determined as the optimal print settings considering time, material cost, and properties. Considering the flexural qualities, the optimized values of layer height, print speed, and infill density were 0.15 mm, 70 mm/s, and 50%, respectively. It was observed that the uniform elongation (UEL) and ultimate stress (UTS) of a component increase as the layer thickness increases for the considered layers.

Flexural strength of 3D-printed temporary materials with different orientations

Flexural strength of 3D-printed temporary materials with different orientations

Mechanical properties of milled and 3D-printed definitive restoration materials

Mechanical properties of milled and 3D-printed definitive restoration materials

Microstructure and compressive behaviour of PLA/PHA-wood lattice structures processed using additive manufacturing

This study investigates the microstructure and compressive behaviour of PLA/PHA-wood lattice structures manufactured using fused filament fabrication (FFF). The primary objective is to evaluate the effects of defects, such as porosity and surface roughness, on the mechanical properties of these lattice structures. X-ray micro-tomography (XRT) and finite element analysis are employed to compare CAD models with real lattice structures, offering insights into defect-induced performance deviations. The novel approach integrates experimental and numerical methods to better understand damage accumulation in porous structures. The methodology includes uniaxial compression testing and image processing for microstructural characterization. Results reveal significant differences in relative density and stress concentration due to manufacturing defects. In particular, 3D printed lattice structures display typical cellular material behaviour with a primary bending deformation mechanism. X-ray tomography reveals that process-induced porosity generate stress heterogeneity, which is not captured from CAD-based model resulting in an overestimation of the stiffness. The study concludes that accounting for these defects can be quantified by shifting the target relative density to compensate lack of performance in 3D-printed lattice materials.

Development of 3D printed zanthoxylum oil waxy rice cake

As an attractive choice for patients with celiac disease, scaling up production and innovating flavors are significant challenges for the development of traditional Sichuan snack, waxy rice cake. 3D food printing is an emerging technology that enables the production of food with the desired shape and structure. This study introduced two types of Zanthoxylum oil to enhance both the printability and quality of waxy rice cakes, aiming to achieve Sichuan-style taste through the Zanthoxylum oil's effect. The results showed that the waxy rice flour dough with Zanthoxylum oil exhibited shear thinning properties, with viscosity decreasing from 292.59 Pa·s to 91.16 Pa·s at a shear rate of 1 s⁻1, making it an ideal material for 3D printing. The addition of Zanthoxylum oil significantly enhanced water activity and hydrogen bonds in the dough system. Furthermore, the incorporation of red Zanthoxylum oil accelerated the dough maturation process. 3D printing and TPA results revealed that sticky rice cakes containing 8% and 12% Zanthoxylum oil exhibited optimal printing accuracy, with the 8% sample achieving 96.69% fidelity. After steaming, the waxy rice cake with 8% Zanthoxylum oil retained a height of 18.23 mm and a diameter of 31.74 mm, with a soft, sticky texture. In summary, the product with the addition of 8% red Zanthoxylum oil exhibited superior appearance and texture, making it suitable for 3D printing. This study is expected to realize the customized production of Sichuan-style waxy rice cake.

Material selection and design of intake blades for aircraft engines based on additive manufacturing

Abstract The intake blades of aircraft engines are mainly used to capture and guide external air into the engine and are the foundation of engine operation. Their materials and design are related to the performance level and reliability of the entire engine. The “additive” 3D printing manufacturing method has the advantages of high precision, low cost, less material waste, strong design, and a short research and development cycle. This article proposes the use of GH4169 high-temperature alloy as the 3D printing material for the service requirements of aircraft engine intake blades, constructs a 3D printing model, and designs and realizes the 3D printing of engine intake blades.

Functionality enhancement of pea protein isolate through cold plasma modification for 3D printing application

Pea protein isolate (PPI) is a valued sustainable protein source, but its relatively poor functional properties limit its applications. This study reports on the effects of cold argon plasma (CP) treatment of a 15 % (w/w) PPI solution on the functionality, structure, and oxidative characteristics of PPI, as well as its application in 3D-printed plant-based meat. Results indicate that hydroxyl radicals and high-energy excited-state argon atoms are the primary active substances. A decrease in free sulfhydryl content and an increase in carbonyl content were observed in treated PPI, indicating oxidative modification. Compared to the control group, the gel strength of PPI was increased by 62.5 % and the storage modulus was significantly improved after 6 min treatment, forming a more ordered and highly cross-linked 3D gel network. Additionally, CP significantly improved the water-holding capacity, oil-holding capacity, emulsifying activity, and emulsion stability of PPI. The α-helix and random coil content in PPI decreased, while the β-sheet content increased, resulting in a more ordered secondary structure after CP treatment. Compared to untreated PPI, the consistency coefficient (K) increased from 36.00 to 47.68 Pa·sn. The treated PPI exhibited higher apparent viscosity and storage modulus and demonstrated better 3D printing performance and self-supporting ability. This study demonstrates that CP can significantly enhance the functional properties of PPI, providing great potential and prospects for improving the printability of 3D printing materials and developing plant protein foods with low-allergenicity.

Comparative Evaluation of Fracture Strength of Implant Supported Crown Fabricated from CAD/CAM and 3D Printed Resin Matrix Ceramic

Objective: To compare fracture strength of screw-retained implant-supported crown of resin matrix ceramic when fabricated using CAD/CAM and 3D printing Material and method: vericom Mazic® Duro (CAD/CAM Nano Hybrid Ceramic) was used as particle-filled composite CAD/CAM material, saremco Print Crowntec (3D printable resins-based) as 3D printed composite material, and the control group was composed of IPS e.max. ZirCAD ivoclar vivadent (zirconia) was used to fabricate mandibular first molar screw-retained, implant-supported crowns. After the fabrication, the crowns were cemented with the Rely X U200 self-adhesive resin cement (3M ESPE, Germany) on stock abutments tightened to analogs embedded in acrylic resin. Finally, all crowns were subjected to a fracture resistance test. fracture strength was evaluated by using one–way ANOVA with Chi-square used for the association between the modes of fracture. Result: The results showed that there were significant differences between all the groups used, the control group (Group zirconia) was significantly higher, as the mean was equal to 6391 N. Followed by Group vericom (cad/cam) with a mean of 2558 N, then Group seramco (3D printing) with a mean of 817.92 N. Dunnett T3 test showed statistically significant differences in fracture resistance between the three groups. There was no significant difference between the modes of fracture and the methods. Conclusion: Screw-retained implant-supported crowns manufactured by CAD/CAM technique had better fracture resistance value than those of the 3D printed technique. Clinical Relevance: resin matrix ceramic is a possible substitute for zirconia in an implant-supported crown

Investigating the Impact of Pore Size and Specification on Soft Tissue Ingrowth in 3D-Printed PEEK Material.

Bone pelvis tumor resection and reconstruction is a complex surgical procedure that poses challenges in soft tissue reconstruction despite advancements in stabilizing pelvic structure. This study aims to investigate the potential of using Polyetheretherketone (PEEK) material in repairing and reconstructing soft tissues surrounding pelvic implants. Specifically, the study focuses on exploring the effectiveness of 3D printed porous PEEK material in promoting cell growth and adhesion. The interaction between PEEK materials with different pore sizes (200, 400, 600µm) and different specifications (through-hole (T)/non-through-hole (C)) is evaluated by cell experiments and animal experiments. The soft tissue ingrowth potential of PEEK materials is evaluated by cell growth and adhesion observation. The findings indicate that PEEK material, particularly the T400 variant, exhibits stronger interaction with muscle tissue compared to its interaction with bone and fibrous tissue. The moderately sized pores present in the T400 material facilitate enhanced cell adhesion and penetration, thereby promoting cell growth and differentiation. PEEK materials with through-hole structures show promise for applications involving the repair and reconstruction of soft tissues and muscle tissue. The study provides valuable insights into the development and application of biomedical materials, specifically PEEK, contributing to the advancement of pelvic tumor resection and reconstruction techniques.

Crashworthiness Investigations for 3D-Printed Multi-Layer Multi-Topology Engineering Resin Lattice Materials.

In comparison to monolithic materials, cellular solids have superior energy absorption capabilities. Of particular interest within this category are the periodic lattice materials, which offer repeatable and highly customizable behavior, particularly in combination with advances in additive manufacturing technologies. In this paper, the crashworthiness of engineering multi-layer, multi-topology (MLMT) resin lattices is experimentally examined. First, the response of a single- and three-layer single topology cubic and octet lattices, at a relative density of 30%, is investigated. Then, the response of MLMT lattices is characterized and compared to those single-topology lattices. Crashworthiness data were collected for all topology arrangements, finding that while the three-layer cubic and octet lattices were capable of absorbing 9.8 J and 7.8 J, respectively, up to their respective densification points, the unique MLMT lattices were capable of absorbing more: 19.0 J (octet-cube-octet) and 22.4 J (cube-octet-cube). These values are between 94% and 187% greater than the single-topology clusters of the same mass.

Sustainable three-dimensional printing of waste paper-based functional materials and constructs

Three-dimensional (3D) printing is a prominent technology across various industrial sectors, and its increasing popularity urgently calls for sustainable 3D printing materials. However, the availability of such materials remains under exploit. Here, we present a low-cost strategy to harnesses waste papers as a feedstock to develop sustainable 3D printing inks. This approach offers a remarkable printability and circular utilisation of biodegradable paper wastes to produce 3D printed constructs, with desired mechanical properties and shape stability for high temperature applications. Our constructs can be efficiently recycled into inks for reprinting, and our method can be applied to various types of waste papers. By employing multi-material printing, our approach can be extended to produce multi-coloured constructs, security information printings, and mechanically appealing designs. This strategy offers an innovative and sustainable solution that addresses the need for repurposing paper wastes, which would otherwise end up in landfills, while concurrently reducing the reliance on virgin plastics for 3D printing.

3D Printing in Biocatalysis and Biosensing: From General Concepts to Practical Applications.

3D printing has matured into a versatile technique that offers researchers many different printing methods and materials with varying properties. Nowadays, 3D printing is deployed within a myriad of different applications, ranging from chemistry to biotechnology - including bioanalytics, biocatalysis or biosensing. Due to its inherent design flexibility (which enables rapid prototyping) and ease of use, 3D printing is facilitating the relatively quick and easy creation of new devices with unprecedented functions. This review article describes how 3D printing can be employed for research in the fields of biochemistry and biotechnology, and specifically for biocatalysis and biosensor applications. We survey different relevant 3D printing techniques, as well as the surface activation and functionalization of 3D-printed materials. Finally, we show how 3D printing is used for the fabrication of reaction ware and enzymatic assays in biocatalysis research, as well as for the generation of biosensors using aptamers, antibodies, and enzymes as recognition elements.

Ultrasound-compatible 3D-printed Franz diffusion system for sonophoresis with microbubbles

Sonophoresis is a topical drug delivery approach that utilises ultrasound as a physical stimulus to enhance permeation of active pharmaceutical ingredients through the skin. Only limited research has however been conducted to evaluate the potential of ultrasound-responsive drug carriers, such as gas microbubbles, in sonophoresis. Franz diffusion cells have been extensively used for measuring drug permeation in vitro; however, traditional systems lack compatibility with ultrasound and only limited characterisation of their acoustical behaviour has been carried out in previous research. To overcome this limitation, we designed and manufactured a novel Franz cell donor compartment coupled with a conventional glass receptor, and performed a functional characterisation of the assembly for application in sonophoresis with ultrasound-responsive agents (specifically imiquimod-loaded gas microbubbles). The donor was fabricated using a photoreactive resin via 3D printing and was designed to enable integration with a therapeutically relevant ultrasound source. The assembly was capable of effectively retaining liquids during prolonged incubation and the absorption of imiquimod onto the 3D-printed material was comparable to the one of glass. Moreover, a predictable ultrasound field could be generated at a target surface without any significant spatial distortion. Finally, we demonstrated applicability of the developed assembly in sonophoresis experiments with StratM®, wherein ultrasound stimulation in the presence of microbubbles resulted in significantly enhanced drug permeation through and partitioning within the membrane (2.96 ± 0.25 μg and 3.84 ± 0.39 μg) compared to passive diffusion alone (1.74 ± 0.29 μg and 2.29 ± 0.32 μg), over 24 h.

Experimental research on the glass fiber-reinforced effect and mechanisms of sand powder 3D-printed rock-like materials

Conducting laboratory tests on natural rocks has significant value for the scientific and practical advancement of various types of rock engineering. The investigation of a rock-like materials that is similar in characteristics and structure to natural rock is key to the further advancement of laboratory rock experiments. The rapid development of sand powder 3D printing technology in recent years has provided a solution for fabricating rock-like materials. However, the low strength and elastic modulus of sand powder 3D-printed materials limit their application in simulating natural rocks. Therefore, this paper proposes a method to enhance the mechanical properties of sand powder 3D-printed materials utilizing glass fiber reinforcement by incorporating glass fiber into sand powder 3D-printed rock-like specimens. The mechanical properties and microstructural variations of the specimens with varying glass fiber contents are investigated utilizing mechanical testing, acoustic emission, scanning electron microscopy, etc. The results indicate that (1) it is feasible to utilize glass fiber to enhance the mechanical properties of sand powder 3D-printed materials; (2) The mechanical properties of sand powder 3D printing materials are significantly enhanced by the addition of glass fiber; and (3) the mechanisms controlling the reinforcement effect of glass fiber addition on sand powder 3D-printed specimens are determined by analyzing the microstructural characteristics of the specimens. This study improves the applicability of sand powder 3D-printed materials in simulating natural rock, thereby promoting the further application of 3D printing in the field of rock mechanics.

Open-source hand prosthesis: evaluation of mechanical feasibility and additive manufacturing potential

This study delves into the risks associated with 3D-printed hand prostheses lacking mechanical feasibility studies. Such unvalidated prostheses may exhibit various issues like durability shortcomings, anatomical incompatibility, functional safety concerns, manufacturing quality deficiencies, and health risks due to inappropriate materials. These issues can lead to damage or premature failure during use, discomfort, skin irritation, injuries, inability to withstand functional loads, and health hazards from toxic or allergenic substances. Therefore, ensuring the safety, quality, and effectiveness of these prostheses is crucial. The study focuses on a mechanical feasibility study conducted through Finite Element Analysis (FEA) simulations on an open-source hand prosthesis model. It evaluates mechanical properties, stress concentration areas, and displacement on the prosthesis surface. The methodology comprises three key steps: acquiring the virtual model, conducting computational simulations, and selecting the 3D printing material. The simulations assess the prosthesis’s ability to withstand compressive forces and identify stress concentration areas. Results from the study indicate that using PETG as the constituent material demonstrates mechanical viability and satisfactory performance under static force conditions. This finding underscores the importance of rigorous testing and adherence to standards in developing 3D-printed hand prostheses. Such studies contribute significantly to enhancing these devices’ safety and effectiveness, facilitating their broader adoption in healthcare settings. In summary, this study highlights the critical need for mechanical feasibility studies in the development of 3D-printed hand prostheses. It emphasizes the significance of following strict standards and regulations to ensure these devices’ safety, quality, and functionality. By doing so, it paves the way for the widespread use of these prostheses in healthcare, benefiting users and advancing the field of prosthetic technology.

Flexural strength, fracture toughness, translucency, stain resistance, and water sorption of 3D-printed, milled, and conventional denture base materials.

To compare mechanical, optical, and physical properties of denture base materials fabricated with various 3D printing systems to reference milled and conventionally heat-processed denture base materials. Specimens of denture base materials were either 3D-printed (DLP in-office printer, CLIP laboratory printer, or material jetting laboratory printer), milled, or heat processed. 3-point bend flexural strength testing was performed after 50 hours of water storage following 1hour of drying (dry testing) or in 37°C water (wet testing). Fracture toughness was performed with a notched beam specimen after 7 days of water storage and tested dry. The translucency parameter was measured with 2mm thick specimens. Stain resistance was measured as color change following 14 days of storage in 37°C coffee. Water sorption was measured following 7 days of storage in 37°C distilled water. For dry testing, all but one of the 3D-printed materials attained higher or equivalent flexural strength as the reference materials. For wet testing, all 3D-printed materials attained higher or equivalent strength as the reference materials and dry-tested materials. For 3D-printed materials, wet testing increased displacement before fracture whereas it decreased displacement for the reference materials. Only two of the 3D-printed materials had similar fracture toughness as the reference materials. One of the 3D-printed materials was more translucent and one was more opaque than the reference materials. Only one of the 3D-printed materials absorbed more water than the reference materials. 3D-printed denture base materials have mostly equivalent mechanical, optical, and physical properties to conventional and milled denture base materials.

Design of a Customized Thumb Prosthesis: Focus on Functionality and Comfort

This research focuses on addressing the scarcity of personalized and affordable prostheses in Honduras by designing and developing a functional prosthesis for a thumb. The general objective was to design a model suitable for 3D printing adapted to the specific needs of a patient who had her index and thumb fingers amputated. To achieve this, an integral methodology was employed, ranging from an exhaustive literature review of current solutions to detailed material evaluations, including interviews with patients and medical experts, SolidWorks modeling, and simulations. The result was the successful design of a functional prosthesis prototype, with the selection of intentionally 3D printable materials to ensure comfort and functionality. In conclusion, this research demonstrates the viability of addressing the scarcity of personalized prostheses through innovative approaches and comprehensive design methodologies, with a focus on effectiveness and streamlining the process.

Comparison of Fracture Strength of Milled and 3D-Printed Crown Materials According to Occlusal Thickness.

This study aimed to measure the fracture strengths and hardness of final restorative milled and 3D-printed materials and evaluate the appropriate crown thickness for their clinical use for permanent prosthesis. One type of milled material (group M) and two types of 3D-printed materials (groups P1 and P2) were used. Their crown thickness was set to 0.5, 1.0, and 1.5 mm for each group, and the fracture strength was measured. Vickers hardness was measured and analyzed to confirm the hardness of each material. Scanning electron microscopy was taken to observe the surface changes of the 3D-printed materials under loads of 900 and 1500 N. With increased thickness, the fracture strength significantly increased for group M but significantly decreased for group P1. For group P2, the fracture strengths for the thicknesses of 0.5 mm and 1.5 mm significantly differed, but that for 1.0 mm did not differ from those for other thicknesses. The hardness of group M was significantly higher than that of groups P1 and P2. For all thicknesses, the fracture strength was higher than the average occlusal force for all materials; however, an appropriate crown thickness is required depending on the material and component.

Eco-Friendly 3D-Printed Concrete Using Steel Slag Aggregate: Buildability, Printability and Mechanical Properties

Utilizing steel slag aggregate (SA) as a substitute for river sand in 3D concrete printing (3DCP) has emerged as a new technique as natural resources become increasingly scarce. This study investigates the feasibility of using steel slag (SS) as fine aggregate for 3DCP. Ninety mixtures with varying steel slag aggregate-to-cement ratios (SA/C), water-to-cement ratios (W/C), and silica fume (SF) contents were designed to study the workability and compressive strength of the 3D-printed concrete. Additionally, the actual components were printed to evaluate the printability of these mixtures. The experimental results indicate that it is feasible to fully employ SA in concrete for 3D printing. Mixtures with slump values ranging from 40 to 80 mm and slump flow values varying from 190 to 210 mm are recommended for 3D printing. The optimal mix is determined to have SA/C and W/C ratios of 1.0 and 0.51, respectively, and an SF content of 10% by cement weight. A statistical approach was utilized to construct the prediction models for slump and slump flow. Moreover, to predict the plastic failure of the 3D-printed concrete structure, the modified prediction model with an SA roughness coefficient of 4 was found to fit well with the experimental data. This research provides new insights into using eco-friendly materials for 3D concrete printing.