Soft 3D printing of thermoplastic polyurethane: Preliminary study

This study evaluates the three-dimensional (3D) printing materials used in Fused Deposition Modeling (FDM) printing technology. 3D printing technology has been developing strongly, becoming an effective support tool in production and research. The 3D printing process involves many stages, with many parameters affecting the quality and properties of the product, in which 3D printing material is one of many essential factors affecting that process. The study conducts a comprehensive assessment of the most common materials in 3D printing technology to determine the advantages and limitations of precisely five types of materials: Polylactic acid, acrylonitrile butadiene styrene, polyethylene terephthalate glycol-modified, thermoplastic polyurethane, and acrylonitrile styrene acrylate. With 3D printing, parameters such as sintering temperature, printing speed, and layer thickness are kept constant. These parameters are applied equally to all five material samples. The experiment evaluates the tensile strength of materials. The study results provide an overview of the properties and applicability of 3D printing materials, helping to select materials suitable for specific FDM 3D printing technology applications.

The application of 3D printing technology has been relatively slow in the fashion industry. Both in the fashion industry and in 3D printing, the material used plays a very important role. In this direction, thermoplastic polyurethane (TPU) is one material that has started to grab the attention of researchers, producers, and customers. While many have studied 3D printing technology using thermoplastic polyurethane material in the fashion industry from different perspectives, fewer researchers have addressed the actual adoption of thermoplastic polyurethane based 3D printing in the fashion industry. Thus, the present research has been focused to propose an adoption model for thermoplastic polyurethane based 3D-printed fashion clothes. Factor analysis was conducted to find and analyse the most relevant factors. Further exploratory factor analysis was conducted to test the proposed model. The study proposed a model for adoption based on four factors: motivation to buy, customer attitude, and the challenges and benefits associated with the adoption of thermoplastic polyurethane based 3-D printed fashion clothes.

Additive manufacturing (AM), also known as 3D printing, has been showing significant growth in recent years. Due to the several advantages, these processes provide, such as high process speed, the possibility for non-conventional geometries and a large range of materials; AM is quickly becoming an industry standard for both prototyping and end-user products. There are several 3D printing technologies available in the market, the most prevalent being fused deposition modeling (FDM), also known by fused filament fabrication (FFF). FDM is widely used as it is highly versatile and has the lowest entry level cost of any AM technology. Due to the layer-by-layer nature of the production procedure, 3D printed materials tend to behave with highly anisotropic properties. The main aspect that governs the anisotropy in FDM is the printing orientation. In order to study these effects, as well as select the optimal materials for future work, bulk specimens were produced from three different materials: polylactic acid (PLA), polycarbonate (PC), and thermoplastic polyurethane (TPU). These specimens were then submitted to tensile testing. In this work, the printing orientations used to manufacture the tested materials were 0°, 45°, and 90° for 100% line infill, with the bulk specimens being produced flat on the printing bed. Steps were taken to prevent layer adhesion failure as well as optimize the production of flexible materials, in this case TPU. The results were then compared with the specifications given by the supplier for FDM and with the raw material properties found in the literature. As expected, for all the specimens, infill orientation played a major role on both tensile strength and elongation. With the results presented in this work, it was possible to select TPU and PC as the most interesting materials to combine, given their broadly different properties. As for future work, a multi-material specimen will be produced, varying the percentage of each material as well as the placement and distribution on the testing bulk.

Textiles are an essential part of human lives and are associated with them from cradle to grave. There is a limitless choice of materials, processes, designs, and applications of fibers and textiles. However, conventional textile processing uses considerable resources and is not always environment friendly. Three-dimensional (3D) printing offers new avenues and provides a considerable value in addition to textile materials. From simple printing of designs or patterns, complex structures such as wearable electronics and space textiles are made using 3D technology. Similarly, the creation of nanostructures, self-colored clothing, and imparting functional finishes are also done through 3D printing. Innovative smart textiles that contain bioactive agents, carbon nanotubes, etc. which can provide high-performance properties, improve appearance or durability, which can be done using 3D printing. One such example is of temperature-regulated clothing developed using 3D printing. In this chapter, we will provide an overview of the opportunities and the challenges of 3D printing in fashion and textiles. Examples include the application of 3D printing in medical textiles, industrial textiles, jewelry, and fashion. Most 3D-printing 190technologies are done using synthetic polymers such as nylon, polyester, poly(lactic acid), and thermoplastic polyurethane. Possibilities of developing 3D-printed objects using natural polymers or other additives have been discussed.

Food 3D printing technology holds significant potential for personalized nutrition and the customization of 3D structures with specific shapes and textures. This emerging technology is driving significant innovations in food processing and manufacturing. This article reviews the current research and development opportunities in food 3D printing, with a focus on various types of 3D food printing technologies. We offer novel insights into the behavioral characteristics of various 3D printing techniques during the printing process, while also highlighting that the successful development of 3D-printed food products relies on four critical factors: (1) adaptability, (2) printability, (3) food safety, and (4) consumer acceptance. Special emphasis is placed on the application and potential challenges of 3D printing technology, aiming to foster technological breakthroughs and industrial applications, ultimately offering consumers safer, smarter, and more personalized food choices.

With the rapid development of the internet of things, the simple preparation of sensors has become a challenge. The present work presents the simple preparation of flexible sensors by using the fused deposition modeling (FDM) 3D printing combined with the microwave radiation‐assisted treatment of the thermoplastic polyurethane (TPU) with carbon nanotubes (CNTs) as conductive fillers to create the flexible sensors. The as‐prepared TPU/CNT composites exhibit the 7.27 MPa tensile strength and 401% elongation at break, similar to those of the pure TPU. After 200 tensile cycles, the TPU/CNT composites can still stably convert pressure into electrical signals, which can be used as flexible sensors with high sensitivity (0.879 kPa−1). In addition, shoe insoles and finger cover with sensing performance are fabricated through the FDM 3D printing technology, demonstrating the potential of the sensors to monitor human gait, finger straightening, and bending movements. The as‐proposed method involves the embedding CNTs as conductive fillers on the surface of TPU to form the TPU/CNT composite conductive layers on the surface of TPU, which is beneficial for maintaining the elasticity of the polymer matrix. The challenges in preparing stable, low‐cost, and scalable flexible sensors and highlights of the advantages of 3D printing technology in manufacturing flexible piezoresistive sensors are also deeply discussed.

3D printing of reduced graphene oxide aerogels for energy storage devices: A paradigm from materials and technologies to applications

Purpose The utilization of three-dimensional (3D) printing in composite materials reduces constraints and opens new possibilities for the development of protective textiles compared to conventional manufacturing processes. Previous studies have predominantly focused on investigating critical parameters that influence the adhesion quality of 3D printed layers on textile substrates, along with the structural characteristics of two-dimensional (2D) textile substrates. However, 3D fabrics with superior properties have not been extensively explored. This study aims to develop innovative 3 days printing auxetic structure–spacer fabric composites with enhanced protection and comfort. Design/methodology/approach Using an entry-level Fused Deposition Modeling (FDM) printer, polymer materials were directly deposited onto 3D spacer fabrics. A series of printing trials determined the optimal process parameters, after which composites with various tilting angles were fabricated. Their deformation behavior and energy absorption characteristics were then evaluated through systematic compression tests. Findings It is found that Thermoplastic Polyurethane (TPU) is more suitable for composite with spacer fabrics compared to Polylactic Acid (PLA). Optimal printing conditions were identified as a speed of 30–40 mm/s, a preheating temperature of approximately 209 °C and an extrusion temperature between 215 and 220 °C. Additionally, an appropriate Z-axis distance effectively combines the 3D printed components with the fabric while maintaining the comfort of the spacer fabric. Composites with a 45°tilting angle demonstrated the best compressive and energy absorption performance under 80 and 50% strain conditions. Practical implications The composites we fabricated with a single-layer thickness below 9 mm, especially the 45° tilting angle structure is only about 7 mm, meeting dimensional requirements for protective equipment (e.g. helmet liners and protective pads). Additionally, the uniform microporous array on the composites surface enhancing breathability without compromising surface smoothness, and contributing to improve comfort in wearable protective applications. The good performance in compressive strength and energy absorption capacity underscoring its potential in applications requiring efficient energy absorption at low strain, such as protective padding and sportswear components. Social implications The increasing demand for personal safety protection has driven the development of high-performance textile composites. Personal protective equipment must not only provide excellent protective functionality but also ensure comfort and portability. Composites with multifunctional gradually replace traditional textiles by balancing protection, flexibility and wearer comfort. Moreover, flexibility of 3D printing can meet the needs of different markets for customization of high-performance personal protective equipment. Originality/value These findings demonstrate the potential of composite materials in applications requiring high energy absorption at low strain conditions and also reflect the promise of integrating FDM 3D printing technology with spacer fabrics for the design and manufacturing of advanced auxetic materials for personal protective equipment.

The cells in conventional packaging foams have random size and orientation, and the energy‐absorbing behaviour of these foams is determined by the collective contribution of different sizes of cells. In contrast to the random nature of stochastic foams, 3D printing technologies allow engineers to design and produce foams having engineered cellular structures. In this study, engineered cellular structures based on the classic Kelvin 1887 model were 3D printed in 30 × 30 × 30 mm thermoplastic polyurethane cubes with a repeating size of 216 unit cells. One hundred consecutive cyclic compression tests were performed to assess the 3D printed foam's resilience and energy absorption characteristics. The stress‐strain curve of the 3D printed thermoplastic polyurethane foam indicated viscoelastic behaviour and a Mullins effect indicative of resilient rubber. A long wave buckling mode was observed during cyclic compression cycles due to the Kelvin structure. The cushion factor computed from the stress‐strain curve was close to that of a metal spring with linear elasticity. The combination of the 3D printed foam's resilience, its much lower density than rubber, and the complete geometric freedom of the engineered cellular structures offer designers the potential to create high‐performance cushion materials tailored for packaging applications.

Influence of thermoplastic polyurethane (TPU) and printing parameters on the thermal and mechanical performance of polylactic acid (PLA) / thermoplastic polyurethane (TPU) polymer

Protective foils for buttons fabricated using 3D printing with TPU (Thermoplastic Polyurethane) material offer innovative solutions for enhancing durability, functionality, and user experience in various applications. TPU, known for its elasticity, abrasion resistance, and transparency, is ideal for creating thin, flexible foils that shield buttons from wear, moisture, and contaminants while maintaining tactile feedback. The 3D printing process allows for precise customization, enabling the production of foils that fit specific button designs with high accuracy. This approach is particularly beneficial in sectors like consumer electronics, automotive, and industrial equipment, where buttons are subject to frequent use and harsh conditions. Moreover, TPU's resilience ensures long-lasting protection without compromising the aesthetic or ergonomic qualities of the buttons. The integration of 3D printing technology facilitates rapid prototyping and production, allowing for quick iterations and tailored solutions to meet diverse protective needs. Overall, the use of TPU in 3D-printed protective foils represents a significant advancement in the design and manufacture of durable, high-performance button covers.

Three-dimensional (3D) printing technologies enables fast prototyping of complex 3D objects with ever improving printing qualities. To date, 3D printing has been found useful in areas such as manufacturing, industrial design, aerospace, dental and medical industries, and many others. In this article, we review recent advances of 3D printing technologies for terahertz (THz) applications. Different 3D printing technologies and printable materials are first discussed and compared. 3D-printed THz components and devices, which are categorized as waveguides/fibers, antennas, and quasi-optical components, are further demonstrated. It is found that the performances and functionalities of 3D-printed THz devices have been greatly enhanced, while the operating frequencies have been increased from the lower end of THz range to over 1 THz region. With further development of novel materials and printing techniques, it is believed that 3D printing technologies will play an important role in the realization of THz components for efficient control and manipulation of THz waves.

For decades we have used printers to print superheroes on the pages of comic books but could printing technologies actually be used to print real life superheroes? 3D and functional printing technologies have advanced greatly in recent years and even though these technologies cannot be used to print heroes themselves, they can certainly be used for equipment manufacturing. One character that could or may use 3D printing to rapidly produce prototypes and final versions of new technologies is Tony Stark. As the inventor and primary user of the Iron Man suit, Stark has designed a wearable suit that is not only a weapon but also protects him. However, in battle the suit can become damaged and require urgent repairs. To aid in these repairs, Tony Stark could turn to 3D printing technologies to produce new components for the suit. In this paper we will outline 3D printing technologies and describe their current applications. We will then discuss how 3D printing is being used to print electronics and the ramifications for Tony Stark, his Iron Man suit and the potential use for a real Iron Man suit.

Leather manufacturing process involves a lot of waste disposal which pollutes environment, some of the processes are inevitable. In the present investigation, 3D printing technology was used to reduce the wastage and to cover defective regions in leather. The present study focuses on synthesis of acrylic binder using emulsion polymerization technique. These binders were analysed for solid content for better optimisation of the amount of binder to be utilised for finishing operation. The experimental binder was prepared with 26% solids. Particle size and thermogravimetric analyses were carried out to understand the size and shape of the particles and their thermal resistance. These binders were used for leather finishing and the performance of leather was studied. Surface morphology changes of leathers were studied using Scanning Electron Microscopy (SEM). Wet and dry rub fastness, finish film adhesion, light fastness and organoleptic properties were studied and found to be superior compared with control leathers. The acrylic finished leather with minor defects was taken for 3D printing and designed using Thermoplastic Polyurethane (TPU) as filament. The acrylic finished leather shows good adhesion for TPU and it results in numerous designs in short duration. The new additive was added to leather using 3D printing technology to produce a tailor-made valuable design without any waste disposal and chemical discharge. This invention may convert the rejected waste leather into valuable material and lead to the new generation hybrid leather for use.

Three-dimensional (3D) printing technology has arrived and is changing a philisophy of “management.” A 3D-printed product is made from a powder or resin and can virtually shape any item from a digital graphics file. This new printing device, however, poses several unforeseen questions. The 3D printing technology calls for time and cost considerations. Once a private firm actually begins to operationalize the new technology, it will have to measure both merit and demerit in terms of a ‘before-and after adaptation’ perspective, in addition to a future prospect of further advantages the device might bring. Similarly, perhaps this is the most important, the use of this new technology might part away with the significant role and function of the core technology in production of different matters. Considering these topics, this study attempts to focus on the 3D printing technology and its influence on technology management. It specifically discusses the impact of 3D printing technology applied to manufacturing companies on their cost, time, quality and activities. To answer this question, a cost structure is developed using the IDKKH method. The cost calculation is also considered using the Cost-Matrix method. After making model and matrix, possibilities are shown as research collaborators and outsourcing selection to organize with the concept of technology management. Through these analyses, problems are clarified, and the discussions indicate the results of introducing 3D printing technology, R & D innovation, and technology management