• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.452-457
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• 2003

As a fundamental study on developing elements with micro shape, micro mold parts machining and experiment of injection molding using it were performed. The ultra precision micro machining system with high functionality was fabricated, and utilized in the machining of micro parts. By using this machining system and micro end-mill tool, a micro circle column structure of high aspect ratio, diameter 60 $\mu\textrm{m}$, height 500 $\mu\textrm{m}$, was fabricated. And a micro lens molds were fabricated by using ball end-mill tool of 300 $\mu\textrm{m}$ diameter and diamond fly-cut tool of 150 $\mu\textrm{m}$ radius. A micro injection molding machine, which is clamping force 1.75 ton, injection capacity 2.8cc, was fabricated for injection molding experiment using micro molds. The injection molding experiment was performed by using the injection molding machine, micro cylinder structures and lens molds. This paper introduces these micro machining system and injection molding machine and demonstrates examples of injection molding using fabricated molds.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.337-341
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• 2002

In these day, micro systems have gained attention with development of advance technologies. Researches about the fabrication of micro parts are actively made in the whole world. Among the researches, technology for micro injection molding machine is one of the key issues for fabrication of micro parts. In this study, we developed a micro injection molding machine for micro parts. To achieve this, injection unit was constructed using a screw with diameter of 12 mm. Clamping unit with clamping force of 1.75 kgf/$\textrm{cm}^2$ was constructed. Also verification test fur fabrication of micro parts was performed. It was performed that the micro injection molding machine can fabricate micro parts based on the result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.623-624
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• 2005

Micro injection molding is a branch of micro system technology and has been under development for the mass manufacture of micro parts. Enhanced technological products like micro optical devices are entering the market. This paper presents fundamental research on the injection molding technique in micro fabrication. In order to successful manufacturing of micro plastic parts, it is necessary to research for development of micro-injection machine, machining of micro mold, decision of optimum injection conditions and the research for polymer material. Therefore in this study, in order to machining of micro mold, a mold core with microscopic V-shaped groove was tooled by ultra-precise tooling machine. The transcription experiments with a polymer, PMMA resin on the surface of core with Ni plating were carried out and surface profile of injected parts was measured with AFM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.85-88
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• 1995

Recently, the micro mold maching techining technology is developed by means of the mechanical and high energy beam process. It is possible to make the micro structure mold with high aspect ratio by the LIGA technology. This mode is used for mass production of plastic parts by the micro injection molding method. In this study, we intend to research on the basic technology of micro injection molding. As the result, we developed the injection molding technology for small column plastic parts which diameter is 500 .mu. m and 200 .mu. m respectively with wbout aspect ratio 20.

• Transactions of Materials Processing
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• v.15 no.9 s.90
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• pp.692-696
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• 2006

Micro fabrication of polymeric materials becomes increasingly important. And it is considered as a low-cost alternative to the silicon or glass-based Micro Electro-Mechanical System(MEMS) technologies. In the present study, micro channels were fabricated via LiGA(Lithographie, Galvanoformung, Abformung) process used for Capillary Electrophoresis(CE) chip. Taguchi method was applied to investigate the effects of process conditions in injection molding(melt temperature, injection speed, mold temperature and packing pressure) on the transcription characteristics of the micro channel. It was found that the skin layer disturbs a formation of micro channel. Furthermore, mold temperature and injection speed were two important factors to affect the replication characteristics of micro channel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1061-1064
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• 1997

Micro injection molding technology is very important fiw mass product of micro structures or micro parts. And, it is so difficult that the molding technology of micro pole or thin wall(barrier rib) structures with high aspect ratio. In this stud). \vc intend to research on the basic technology of micro wall structure part:< with high aspect ratio by the inject~on moldins method. The mold for esperimenrs with micro multi-square structures was made by L, I(;A process. One square polc's size is 157 157pm. height 50011111. And the distance of each poles is 5011n1. 7'hus. molding products will be for~nctl like as the net structure with thin wall of about 50pn thickness.(aspect ratio 10) Ihrough the e~lxriment. \be obtained the prociuctr of micro multi-square slructure with bout 37.000 cell per a piece. 'Ihe micro injection molding process technolog for thin wall by multi-square structure mold was analy~cd.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.60-63
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• 2009

Manufacturing technologies of micro spur gear and micro mold by micro PIM were studied with stainless steel feedstock. For molding of gears, micro mold with gear cavity of 1.2 mm in diameter was produced by wire EDM. The proper injection pressure was selected to 70bar by observation and measuring of shapes and shrinkage of gears before/after sintering. For fabrication of micro mold, a tiny polymer gear was produced by injection into the mold. Then, 316L feedstock was again injected/compressed on the polymer gear and debinded together with polymer gear followed by sintering. As a result, another metal mold with gear cavity reduced to about 20% was fabricated and through repetition of this process chain, micro gear mold with cavity about below 800 um was finally obtained. In reduction of size by injection/compression molding, height of gear tooth was shrunk more and the effort for decrease of roughness of micro cavity were carried out ultrasonic polishing and as a result, the roughness in cavity decreased from 3-4 um to about 200 nm.

• Design & Manufacturing
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• v.2 no.5
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• pp.11-15
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• 2008

A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.267-270
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• 2004

In Micro injection process, it is needed to the technique of making micro die, Rapid Thermal Pressing (RTP) and other techniques. Those techniques are independent. But the mutual connected system of techniques is needed. The target of this paper is the design of micro mold and the development of the entire micro injection techniques for functional polymer.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.47-56
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• 2007

Recently, demands on mechanical micro machining technology have been increased in manufacturing of micro-scale precision shapes and parts. The main purpose of this research is to verify the accuracy and cost efficiency of the mechanical micro machining. In order to measure the precision and feasibility of mechanical micro machining, various micro features were machined. Aluminum molds were machined by a 3-axis micro stage in order to fabricate microchips with $200{\mu}m$ wide channel for capillary electrophoresis, then the same geometry of microchip was made by injection molding. To evaluate the cost efficiency of various micro manufacturing processes, cost estimation for mechanical micro machining was conducted, and actual costs of microchips fabricated by mechanical micro machining, injection molding, and MEMS (Micro electro mechanical system) were compared.