| POLYMERS Vol.72 No.4 |
| >> Japanese | >> English |
COVER STORY
New Trends in Plastic Molding and Processing and Plastic Product Design |
| COVER STORY: Highlight Reviews |
| Expansion of Expression Space of 3D Printer Using Architected Materials and its Application to Manufacturing | Jun MORITA |
| <Abstract> Regarding manufacturing using 3D printers, it is important to ensure the flexibility of not only the shape but also the material properties expressed by conventional polymer materials, especially when considering the final product manufacturing. In this report, we present our efforts on “physical property control technology for macro 3D shape by unit structure” and “technology for incorporating end-user’s sensibility into digital design” using Architectd Material. Taking advantage of the high-definition modeling performance of recent 3D printers, it is possible to express characteristics beyond the constraints of materials by actively controlling the hierarchical structure using Architected Materials. Also, the design parameters of Architected Material correlated with the Japanese onomatopoeia syllables of evaluators who actually evaluated the product. In order to expand the personalized manufacturing that is a feature of 3D printers, further research and development is expected in parallel with the development of systems and interfaces that enable designs that make use of the user’s sensibility. Keywords: 3D / Architected Material / Metamaterials / Design System / Personal Fabrication / Additive Manufacturing / Lattice / Foam |
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| Nanoimprint Processes and Materials for Meta-Optics | Masaru NAKAGAWA |
| <Abstract> The advent of metaoptics such as metalenses of thin flat optical elements has led to revolutionary improvements in the performace of imaging devices. From the early stage, metaoptics have been made from inorganic materials with a high refractive index through semiconductor technology involving electron beam lithography. Recently, moldable materials with a refractive index of larger than 1.9 have begun to appear for nanoimprinting. Thus, researches of metaoptics using moldable materials incease. For the development of this reaerch field, innovative materials with optical properties, modability, and mass producibility are required. Keywords: Optical Metamaterials / Metaoptics / Metalense / Thin Flat Optical Element / High Refractive Index / Nanofabirication / Nanoimprinting / Nanoparticle Composite |
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| Binder Jetting Technology for Metal Parts Manufacuturing | Shinichiro SATO |
| <Abstract> Additive Manufacturing (AM), known as 3D printing, is the method to build the materials through a layer-by-layer process. AM can be applied to virtually any material using a variety of techniques. We succeeded in developing the binder jetting technology (BJT) to make a new value creaction, such as good heat exchange capabilities. The BJT process has issues regarding the quality of the metal parts that depend on the sintering process. To achieve a good accuracy and density of the parts, it is necessary to get the green parts with high packing density and simulating the shrinking deformation for green parts to sintering parts. We will introduce research trends aimed at these key items and more. Keywords: Additive Manufacturing / Binder-Jetting Technology for Metal / Aluminum |
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| Concept of Topology Optimization and Its Applicaton to Structural Designs | Shinji NISHIWAKI |
| <Abstract> Topology optimization is the most flexible type of structural optimization because topological changes as well as shape changes are allowed, and it provides high performance structures and has the potential to implement new structural functions. In this article, first, a basic concept is briefly explained. A key idea is the replacement of the structural optimization method with a material distribution problem, and it leads an infinite number of discontinuities in the design domain. The three types of methods, i.e., homogenization design method, density approach, and level set-based method, are explained to mitigate this discontinuiy problem. Finally, three design examples, i.e., strucural design, fluid mechanics design, and thermal-fluid coupled design example, are provided to show the utility and availablity of topology optimization. Keywords: Structural Optimization / Topology Optimization / Computer Aided Engineerig / Finite Element Method |
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| COVER STORY: Topics and Products |
| Designing Softness Using Additive Manufacturing Technology | Mitsuru MURAMATSU |
| <Abstract> The Additive Manufacturing (AM) technology enables making complex mechanical structures and it expands the possibilities in manufacturing. The author and the Prototyping & Design Laboratory at the University of Tokyo are exploring the possibilities of AM technology and creating prototypes that can be only made by AM. In this article, the author introduces several research projects exploring AM technology mainly focusing on the design of texture and tactile sensation made by complex structure. In product design, the parts that the user touches and holds are oftenly designed to be soft or elastic by using materials like elastomers. “Structured Texture” is a project designing texture and tactile sensation using complex milimeter-scale structures so called mechanical metamaterial. Researcher designed a Lizard model using Structured Texture which gives us a feeling as if we hold a real lizard. Later in the article, the author introduces recent studies exploring the possibility of designing wearable systems using AM and mechanical metamaterial. Keywords: Additive Manufacturinig / Design / Prototyping / Texture / Mechanical Metamaterial / Wearable Systems |
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| Preparation of Three Dimensional Products Using Flow Deformability of Wood Treated by Chemical Modification | Mitsuru ABE, Masako SEKI, Tsunehisa MIKI |
| <Abstract> Converting wood into thermoplastic materials is an attractive methods of increasing its utilization because complex three-dimensional molded products can easily be obtained by press molding. Esterification is a promising method for imparting thermoplasticity into wood. Hydroxyl groups in block-shaped wood were replaced with ester groups to realize plastic formation. The modulus of elasticity of the esterified wood decreased remarkably when heated. Additionally, the esterified wood was stretched extensively by pressing with heat, showing its fluidity. In addition, it was found that the deformability of wood can be controlled by the appropriate selection of an esterification method and its treatment conditions even in the case of similar degree of substitution with the same ester groups. Plastic formation using propionylated wood was attempted, and a cup-shaped three-dimensional product was successfully formed. The cup-shaped molded product exhibited high water resistance. Re-forming was also successfully demonstrated using crushed fragments of the cup-shaped molded product. Keywords: Wood / Flow Forming / Thermoplasticity / Deformability / Esterification / Hot-Press / Water Resistance / Re-Molding |
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| Development Trends of Metal and Resin Jointing Technology During Insert Molding Process | Goro INOUE |
| <Abstract> Development trends of metal and resin jointing technology during insert molding process are reviewed. Since the insert molding jointing method is superior in terms of suppressing thermal deterioration and shortening the process, its use in automobile parts and electronic equipment parts is expanding. Until now, there have been concerns about maintaining bonding strength and airtightness due to environmental changes, especially thermal shock loads, but each company has been working to improve them, and it has been shown that they get a certain level of long-term reliability. In addition, even for resins that have been considered difficult to insert molding and bonding, it is found that reliable bonding interfaces can be formed not only by improving the metal surface treatment and resin composition, but also by devising injection molding methods. Keywords: Metal and Resin Jointing Technology / Insert Molding Jointing Method / NMT / Polymetac™ / Lazeridge / Durability / Amorphous Resin / H&C Molding |
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| Polymer Science and I: A Personal Account |
| Being Passionate | Xiang LI |
| <Abstract> My research interests cover many soft materials, including polymer solutions, colloids, gels, and biological tissues. In particular, I am engaged in elucidating the underlying mechanisms between macroscopic properties and the nanostructures of soft materials by combining structural analysis using light, X-ray, and neutron scattering and rheological techniques. |
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| Front-Line Polymer Science |
| Recent and Future of Flexible Organic Light Emitting Diode Displays | Masanobu MIZUSAKI |
| <Abstract> The market of flexible displays is noticeably growing in the recent few years. This article focuses on component parts and new fabrication method of flexible organic light emitting diode (OLED) displays. In particular, flexible substrates and the sealing technology are important for maintaining both high flexibility and reliability. The important factors for the polymer flexible substrates are high transmittance, thermal stability, low birefringence, high gas barrier property, soluble agent resistance, smoothness, and suitability for fabrication processes. The sealing technology thin film encapsulation, which is composed of inorganic and polymer layers, is a good solution for both moisture and gas barrier properties. Furthermore, a new fabrication method was recently proposed for high definition OLED displays employing an orthogonal processing method that uses a fluorous resist and solvent materials. Keywords: Organic Light Emitting Diode Displays / Flexible / Substrate / Thin Film Encapsulation / Evaporation / Orthogonal Processing / Fluorous Materials |
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