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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Finite Element Analysis of Micro-cutting Aluminum 7050-T7451 with the Tool Edge Radius Considered

    Jun ZhouJianfeng LiJie Sun
    P.663-668页
    查看更多>>摘要：In this paper, a series of simulation works by finite element method for predicting the temperature and the plastic strain distributions in micro cutting process with the tool edge radius considered were conducted. The workpiece is Aluminum alloy 7050-T7451 and its flow stress is taken as a function of strain, strain rate and temperature in order to reflect realistic behavior in machining process. From the simulation works, a lot of information on the micro-machining process can be obtained, such as cutting force, cutting temperature, distributions of temperature and plastic strain, etc. In addition, explanations for the observed trends are also given.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Design of a Fast Tool Servo based Diamond Turning Machine for Fabricating Micro-structured Surfaces

    De Ping YuSze Wei GanYoke San WongMustafizur Rahman...
    P.669-674页
    查看更多>>摘要：Increasing demand for ultraprecision components with micro-structured surfaces has attracted focus on diamond turning research. In this paper, a fast tool servo (FTS) based diamond turning machine is presented for fabricating micro-structured surfaces with high accuracy. A design criterion is established to serve as a guide in choosing or designing a suitable type of FTS for a micro-structured surface. Experiments on fabricating sampled micro-structured surfaces are carried out to demonstrate the effectiveness of the designed FTS based diamond turning machine.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Erosion Mechanism of Ultrasonic Vibration Abrasive Waterjet in Micro Machining

    Hongtao ZhuChuanzhen HuangJun WangZengwen Liu...
    P.675-680页
    查看更多>>摘要：In this paper, a study on erosion mechanism of Ultrasonic Vibration Abrasive Waterjet is presented. Theoretical analysis of the total effective erosion kinetic energy of UVAWJ is performed. By using a UVAWJ machining system with an Ultrasonic Vibration Power Workbench, the comparative experiment is conducted. The erosion surfaces of the single crystal silicon substrate were measured by Optical Profiler and observed with Scanning Electron Microscope. The material removal mechanisms are discussed. It is concluded that the erosion by UVAWJ, with the aid of high-frequency ultrasonic vibration, can obtains a high material removal, less cracks and good finish surface.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Migration of Materials during Finishing Micro-EDM of Tungsten Carbide

    Muhammad Pervej JahanMustafizur RahmanYoke San Wong
    P.681-686页
    查看更多>>摘要：Present study aims to investigate the migration of materials onto the surface of workpiece and electrode during fine-finish die-sinking and milling micro-EDM of tungsten carbide using pure tungsten electrode. The effect of materials transfer on the machined surface characteristics is also presented. The machined surfaces have been examined under scanning electron microscope (SEM) and energy dispersive X-ray (EDX) in order to investigate the changes in chemical composition due to the migration of materials. It has been observed that materials from both workpiece and electrode transfer to each other depending on machining conditions and discharge energy. A significant amount of carbon migrates to both electrode and workpiece surface due to the decomposition of dielectric hydrocarbon during breakdown. The migration occurs more frequently at lower gap voltages during finish die-sinking micro-EDM due to low spark gap and stationary tool electrode. Milling micro-EDM suffers from lower amount of carbon migration and fewer surface defects which improve the overall surface finish and reduce surface roughness significantly.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Thermal Effect Analysis of Femtosecond Laser Scribing of Silicon

    Daping WanPhilip MathewJun Wang
    P.687-692页
    查看更多>>摘要：Ultra-short pulsed laser ablation of crystalline silicon is characterized by a complicated heat diffusion process. In this research, a computational investigation is undertaken to achieve the temperature distribution and heat effect as a function of micromachining parameters. Heat accumulation and heat affected zone (HAZ) of silicon ablation by ultra-short lasers are estimated through solving coupled energy balance equations. The laser energy deposition and possible non-thermal ablation process are analyzed in the case of succession of laser pulses. Thermal-mechanical response induced by temperature gradient is discussed around the laser ablation region. The agreement between the model calculations and experimental results show that this research provides an efficient thermal analysis method, and a feasible way to optimize process parameters with minimum thermal damages.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A Comparison of Dry and Underwater Laser Micromachining of Silicon Substrates

    Viboon TangwarodomnukunJun WangPhilip Mathew
    P.693-698页
    查看更多>>摘要：Laser micromachining has been widely used for decades to fabricate the micro- and submicro-component structures. However, thermal and physical damages are crucial issues associated with the process. Underwater laser ablation has been developed as a damage-free micro-ablation technique. In this paper, a comparison of the conventional dry and underwater laser micromachining of silicon is presented. It shows that the heat affected zone (HAZ) can be reduced significantly in the underwater laser process, though the material removal rate is reduced due to the energy loss by the water layer. The effects of pulse frequency, traverse speed and laser energy on the obtained kerf width, HAZ and cut surface quality are also analyzed and discussed.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Laser Dieless Drawing Process for Metal Micro-tubes

    Tsuyoshi FurushimaYuta NodaKen-ichi Manabe
    P.699-704页
    查看更多>>摘要：A drawing process using tools such as dies, plugs and mandrels has been conventionally applied as a means of miniaturizing tubes. However, it is not easy to scale down the conventional process to micro sizes for many reasons related to the tools used in the process. It is difficult to fabricate micro tools with high accuracy, and to insert a plug or a mandrel into a fine tube. Thus, the development of new drawing technologies for the fabrication of micro-tubes without the need for tools such as dies, plugs and mandrels is necessary. A laser dieless drawing technique with local heating using a laser as the heating source has been focused on for the fabrication of micro-tubes. In this study, a dieless drawing with a semiconductor laser setup is designed and developed. A tube of stainless steel, SUS304, with an outer diameter of 0.52mm and thickness of 0.1mm is used in the experiments. A laser dieless drawing experiment is carried out to investigate the effect of the laser power and drawing speed on the drawing limit. Finally, the effectiveness of laser dieless drawing process is discussed.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Parameter Optimization towards Highest Micro MIM Density by Using Taguchi Method

    Mohd Halim Irwan IbrahimNorhamidi MuhamadAbu Bakar SulongKhairur Rijal Jamaludin...
    P.705-710页
    查看更多>>摘要：Nowadays, micro metal injection molding has become among the promising method in powder metallurgy research to produce small-scale intricate part at an effective process and competitive cost for mass production. This paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. In this paper, stainless steel SS 316L with D_(50) = 5.96μm was used with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid). Feedstock with 61.5% with several injection parameters were optimized which highly significant through screening experiment such as injection pressure(A), injection temperature(B), mold temperature(C), injection time(D) and holding time(E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchi's orthogonal array. Analysis of variance (ANOVA) in terms of signal-to-noise ratio (S/N-larger is better) for green density was also presented in this paper. Result shows that interaction between injection temperature and mold temperature(B×C) give highest significant factor followed by interaction between injection pressure and mold temperature(A×C). Single factor that also contributes to significant optimization are mold temperature(C) and injection time(D). This study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Surface Modification of Plastic Thin Film Using Anodic Aluminum Oxide Template for Nano Imprint

    Chih-Wei WuJeou-Long LeeYi LinYung-Kang Shen...
    P.711-716页
    查看更多>>摘要：Nano-porous anodic alumina oxide (AAO) templates are fabricated by anodizing method. The average diameter of nano-porous anodic alumina is 200 nm. The molded plastic thin film (Polycarbonate, PC) with nano-structure is fabricated by AAO as mold insert for nanoimprint. This research discusses the surface property of molded plastic thin film for different processing parameters (embossing temperature, embossing pressure, embossing time, de-molding temperature) on nanoimprint. The original contact angle of PC material without nano-structrue is about 78.2°. The contact angle of molded PC with nano-structrue is about 115.5°. The contact angle of molded plastic film (PC) with nano-structure is larger than that without nano-structure. The hydrophilic property of PC material has changed to hydrophobic property. A significant advantage of the fabrication process employed in this work is that it can create the good surface modification of plastic thin film.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Improvement on Yield of Anisotropic Conductive Film Attach Process in TFT-LCD Module Using Taguchi Method

    Jian-Long KuoKai-Lun ChaoChung-Hao Hsieh
    P.717-722页
    查看更多>>摘要：Anisotropic Conductive Film (ACF) is one of the important materials in LCM (Liquid Crystal Module) process, it is used in bonding process to make the driving circuit conductive. Because the price of TFT-LCD is much lower than before in recent years, the ACF cost has higher ratio in manufacture cost. The conventional long bar ACF attach unit is changed to short bar ACF attach unit in new bonding equipment. However, the new type machine was not optimized in process and mechanical design. Therefore, the failure rate of ACF attach process is much higher than the one of conventional method. This wastes the material and rework cost is also invisible. How to make the manufacturing cost down effectively and promote the product quality will be the important concern to keep the product competition. Therefore, the Taguchi method is used to analyze the problem. The ACF attach yield rate is selected to be objective function for optimization. By the optimization of quality characteristic using Taguchi method, the plasma clean speed, ACF peeling speed and ACF cutter spring setting are studied to optimize the design parameters.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd