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International Conference on (ICEPT) Electronic Packaging technology

作者： Fan Wu Yiping Wu Bing An Fengshun Wu State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan China

In the process of aging or in service of some high power blue LEDs, dark stain may occur on the LED chip surface, which cast a shadow over the chip and thus led to the losing of luminous flux. In the degraded samples, it was found that firstly the dark stain was formed on the chip surface equably, and then the color of this stain gradually darken with time. In this paper, this kind of dark stain was detected and analyzed. The morphology of the dark stain and the elements contained in it were measured by scanning electron microscopy (SEM) and energy dispersive analysis by X-ray (EDAX), respectively. A large mount of oxygen and carbon were found in the black zones, which implied that some chemical reactions occurred on the interface. After we removed the black materials off the chip surface, the quantity of luminous flux evidently increased. The origin of oxygen and the possible reason of the dark stain were also discussed

关键词： Light emitting diodes Surface morphology Degradation Scanning electron microscopy Temperature laboratories Aging Dispersion Electrodes Indium tin oxide

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Study on laser machining technique for direct rapid metal tooling

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Zhongguo Jixie Gongcheng/China Mechanical Engineering 2006年第SUPPL.期17卷 246-248页

作者： Cao, Biao Zhang, Haiou Wang, Guilan State Key Lab of Plastic Forming Simulation and Die and Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

In order to improve the dimensional accuracy and surface roughness of Direct Rapid Metal Tooling(DRMT), a laser bevel cutting technique for DRMT was proposed. Through the systemic experiments, the effects of parameter... 详细信息

关键词： DRMT Laser machining Microstructure Surface roughness

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The application of injection molding simulation in mold design

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Zhongguo Jixie Gongcheng/China Mechanical Engineering 2006年第SUPPL.期17卷 198-200页

作者： Sun, Qiang Zhou, Huamin Huang, Zhigao Li, Dequn State Key Lab of Plastic Forming Simulation and Die and Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

In the design of plastic mold with multicavity, it is the emphasis and difficulty to get the rational dimensions of gate and runner to ensure the same molding pressure and temperature and to fill the cavities at the same time. An optimization algorithm of runner and how to simulate flow, cooling and optimize process with HSC3DRF are discussed in which emphasis is put on the nonnatural balanced runner system.

关键词： Cooling simulation Flow balance Flow simulation Plastic molding

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Microstructure of metal-based solid self-lubrication coating by laser cladding

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Zhongguo Jixie Gongcheng/China Mechanical Engineering 2006年第19期17卷 2084-2088页

作者： Zhang, Xianglin Zhang, Xiaofeng Wang, Aihua Qiao, Xiaoyong State Key Lab Plastic Forming Simulation and Die and Mould Technology Department Huazhong University of Science and Technology Wuhan 430074 China

In aluminium alloy sheet forming processes, the development of an effective and environmental-protective lubricating technique is becoming very important to overcome the high temperature lubrication problems. The metal-based solid self-lubrication coatings were produced by Nd: YAG and CO2 lasers cladding through choosing composite powder containing Ni45, CaF2 and WS2. Microstructures of two kinds of clad coatings were investigated to understand the corresponding formation mechanism. Results show that CO2 laser is much more suitable for the preparation of the Ni45-CaF2-WS2 coating than Nd: YAG laser.

关键词： Mechanism Metal-based solid self-lubrication coating Micro-structure YAG and CO2 laser cladding

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New layer data file format for rapid prototyping

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Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and technology (Natural Science Edition) 2006年第5期34卷 86-88页

作者： Zhang, Lichao Huang, Shuhuai State Key Lab. of Plastic Forming Simulation and Die and Mould Technol. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

A new layer data file format, ZIF format, was proposed to improve the original layer data file formats, such as SLC and CLI formats, for rapid prototyping. The new format was based on the tree-structure of information block. The total information (layer data, technical parameters and STL solid information) were stored in only one file. With the advantage of the index of information blocks, the data of every layer were accessed in real-time. An information block for user-defined parameters would support the storage of special data of every rapid prototyping technique. By means of new information blocks, the file format would be extended for the future. The criterion, access method and applications of ZIF format were also discussed.

关键词： Rapid prototyping

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Robotic milling for rapid ceramic pototyping

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Journal of Harbin Institute of technology(New Series) 2005年第6期12卷 674-679页

作者：韩光超张海鸥王桂兰 State Key Lab. of Plastic Forming Simulation and Die & Mould Technology Huazhong University of Science & Technology Wuhan 430074 China

Robotic milling is a developing method for rapidly producing prototypes and parts, but the application is limited for materials such as wax, wood, plastic and light metal, etc. The reason for this is because of the robotic weak rigidity. In this paper, a method of robotic milling for ceramic prototyping is developed, one that has been successfully applied in a new rapid hard tooling technology-Direct Prototype Spray Tooling. At first, the appropriate ceramic materials mixed with metal powder are confirmed for the robotic milling and the following plasma spraying process. Then the 6 - DOF robotic milling paths are extracted from the NC code and transformed into the robotic JBI type file, the NC code generated through the general CAD/CAM software such as UG -NX. Finally, the robotic milling characteristics such as moving path accuracy and milling force are tested to find the best milling parameters and to ensure the executable, accurate and efficient ceramic prototype milling technology. The development of this method not only broadens the robotic milling material range but also extends the rapid prototyping fields. It can also be used for producing ceramic parts that are difficult to machine.

关键词： robot milling ceramic prototyping milling characters

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Synthesis and Performance of Transparent Casting Polyurethane Resin

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Journal of Wuhan University of technology(materials Science) 2005年第2期20卷 24-28页

作者：薛峰 State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Senior Engineer

A series of transparent casting polyurethane resins (TCPU) were synthesized from cycloaliphatic diisocyanate (IPDI or H_(12)MDI), polyol, chain extender, crosslinking agents, catalyst and special aids (T),which were characterized by FTIR. The thermal stabilities of the obtained TCPU were examined by DSC and TGA, the glass transition temperature (T_g) was in the range of 95-110 ℃, the initial decomposition temperature (5% weight loss) was 250-265 ℃, and 10% weight loss at the temperature was in the range of 260-286℃ in nitrogen atmosphere. The morphologies of the fractured surfaces of TCPU were revealed by a scanning electron microscope (SEM). The crystalline-amorphous characters of TCPU were studied by WAXD, the result shows that TCPU possesses amorphous glassy characters. The optical properties of TCPU were studied by a UV-7500 visible light absorbance measurement. All the samples exhibited excellent optical properties and possessed light transmittance in the range of 91%-93%.

关键词： transparent casting polyurethane resin thermal stability optical property morphology mechanical property

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Synthesis of A Novel Photosensitive Prepolymer with Trimethylolpropane Triglycidylether and Acrylic Acid as Starting materials

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Journal of Wuhan University of technology(materials Science) 2005年第2期20卷 29-31页

作者：黄笔武 State Key Laboratory of Plastic Forming Simulation and Die & Mould Technology School of Material Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Senior Engineer

A novel photosensitive prepolymer of trimethylolpropane triglycidylether triacrylate was synthesized by utilizing trimethylolpropane triglycidylether and acrylic acid as two starting materials, triphenyl phosphine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthesis conditions were that the concentration of triphenyl phosphine was 0.85wt% of reactants, the concentration of p-hydroxyanisole was 0.3wt% of reactants, and the reaction temperature was at 90-110 ℃. Benzil dimethyl ketal of a UV-cured initiator was added to the synthesized trimethylolpropane triglycidylether triacrylate to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 28.43 MPa of tensile strength, 965.59MPa of (Young's) modulus and 4.10% of elongation at tear.

关键词： synthesis trimethylolpropane triglycidylether acrylic acid UV-cured film

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Wetting dynamics study of Sn-Ag solder during reflow

Wetting dynamics study of Sn-Ag solder during reflow

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2005 Conference on High Density Microsystem Design and Packaging and Component Failure Analysis, HDP'05

作者： Li, Song An, Bing Zhang, Tong-Jun Wu, Yi-Ping State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

ISBN: (纸本)0780392930

At present, solder joints are widely used to bond chips to their substrates for electronic connection and packaging. Good wettability is an essential requirement to form electronic interconnects. In this paper, an image acquisition system was used to observe time-dependent contact angle variation of 96.5Sn-3.5Ag lead-free BGA solder ball on Cu substrate. The wetting dynamics of the solder materials were investigated on Cu substrate, with two flux systems, at different heating temperatures. The results showed that an increase in temperature accelerated the wetting rate of solder significantly. The kind of flux had a large effect on the dynamics of solder wetting. The Suk's model was discussed to validate the experiment results.

关键词： Soldering alloys

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Enhanced Interfacial Adhesion in HDPE/HA Composites by Surface Modification of HA Particles via in situ Polymerization and Copolymerization

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Journal of Wuhan University of technology(materials Science) 2005年第B12期20卷 48-51页

作者：龚兴厚解孝林 Department of Chemistry Huazhong University of Science and Technology Wuhan 430074 China Department of Chemistry Huazhong University of Science and Technology Wuhan 430074 ChinaState Key Laboratory of Plastic Forming Simulation and Die & Mould TechnologyHuazhong University of Science and TechnologyWuhan 430074 China

Hydroxyapatite （ HA ）- reinforced high density polyethylene （HDPE） was developed as a bone replacement material,In order to enhaace the interfacial bonding between HA and polyethylene and improve the mechanical properties of HDPE/ HA composites, the surface of the micron-sized HA particles was modified by in situ polymerization of butyl acrylate （ BA ） and in situ copolymerization of vinyl triethoxyl silane （ VTES ） and BA , then the modifwd HA particles were compounded with HDPE. The effects of the surface modification of HA on morphology and mechanical properties of HDPE/ HA composites were investigated. The experimental results show that the presence of HA particles does tuft inhibit the polymerization of BA . The poly（ butyl acrylate）（ PBA ） segments on the HA surface enhance the compatibility between HA and HDPE, improve the dispersion of HA particles in HDPE matrix, and enhance the interfacial adhesion between HA and matrix. Surface modifieations , especially by in situ copolymerization of VTES and BA, significantly increase notch impact strengths and marginal stiffness and tensile strengths of HDPE/HA composites. And it is found that there is a critical thickness of PBA coating on HA panicles for optimum mechanical properties of HDPE / HA composites.

关键词： high density polyethylene hydroxyapatite surface modification in situ copolymerization

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