• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.171-175
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• 2001

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectrics and metal, which can apply to employed in integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of free-defects in inter level dielectrics and metal. Especially, defects like (micro-scratch) lead to severe circuit failure, and affects yield. Current conditioning method - bladder type, orbital pad motion - usually provides unsuitable pad profile during ex-situ conditioning near the end of pad life. Since much of the pad wear occurs by the mechanism of bladder tripe conditioning and its orbital motion without rotation, we need to implement new ex-situ conditioner which can prevent abnormal regional force on pad caused by bladder-type and also need to rotate the pad during conditioning. Another important study of ADPC is related to the orbital scratch of which source is assumed as diamond grit dropped from the strip during ex-situ conditioning. Scratch from diamond grit damaged wafer severely so usual1y scraped. Figure 1 shows the typical shape of scratch damaged from diamond. We suspected that intensive forces to the edge area of bladder type stripper accelerated the drop of Diamond grit during conditioning, so new designed Flat stripper was introduced.

• The KSFM Journal of Fluid Machinery
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• v.11 no.5
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• pp.7-14
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• 2008

Open channel type regenerative pump has been used in various industrial fields. It generates high pressure with low flow rate. However, it has low efficiency because of its complex flow pattern, We studied performance experiments and 3D numerical flow analysis of a regenerative pump. Through the numerical analysis, we could get the internal flow pattern and profile of a regenerative pump. Also, we examined leakage flow effects due to the gap between casing and impeller and stripper clearance. For the numerical analysis verification, we performed experiments and they had similar tendency at the design point.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.213-216
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• 2001

A micro hole punching system was developed and micro holes of 100m in diameter were successfully made on brass sheets of loom in thickness. A micro punch made of tungsten carbide was designed to withstand the punch load, considering the buckling and the bending moment due to possible misalignment error. The punch was fabricated by the grinding process with diamond wheel. The die was designed considering the punch load and fabricated by micro electrodischarge machining process. In this system the stripper is designed to guide punch tip to minimize the possible misalignment. The punch was installed on a vertical stepper and the die was mounted on an X-Y translation unit. The precision motion controller controlled all motions of the micro hole punching system. In this study technical difficulties and solutions in the micro hole punching process were also discussed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.146-150
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• 2000

In order to prevent the defects, the optimum design of the production part, strip process layout, die design, die making and try out etc. are necessary the analysis of effective factors. For example, theory and practice of metal shearing process and it's phenomena, die structure, machine tool working for die making, die materials and it's heat treatment, metal working in field, their know how etc. are included in those factors. In this study, we analyzed whole of data base, theoretical back ground of metal working process, and then performed the progressive die tryout with the screw press. Part2 of this study reveals with ultra precision progressive die design, its making and tryout.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.35-39
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• 2000

The piercing and blanking of thin sheet metal working is specified division in press die design and making. In order to prevent the detects, the optimum design of the production part, strip process layout, die design, die making and try out etc. are necessary the analysis of effective factors. For example, theory and practice of metal shearing process and its phenomena, die structure, machine tool working for die making, die materials and its heat treatment, metal working in industrial and its know how etc. In this study, we analyzed whole of data base, theoretical back ground of metal working process, and then performed the progressive die tryout with the screw press. This study regards to the aim of small quantity of production parts press working. Part 1 of this study reveals with production part and strip process layout design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.92-96
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• 1997

Recently, the life cycle of products is rapidly shortened and then the disposal of the used mold applied in development of the product is a difficult thing. In this study, we proposed the feasibility of new 3plate type mold base for recycling by analyzing of the existing standard mold base. And in order to apply new 3plate mold base in mold design and making, we constructed the specifications for parts such as runner stripper plate, cavity plate, core plate and slide core unit. Also, we confirmed the possibility of recycling mold base by testing a used 3plate mold for a Audio front pannel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.3
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• pp.50-57
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• 1996

This study was performed the blankholding force and Vee-ring effects on blanking characteristics, such as maximum blanking force, burnish, dish-shape, hardness. etc. in fine-blanking die by the experimental method. Two types of aluminum (Al.1050-O, Al, 5052-H) Such as annealed and unannealed materials were used for the experiment. In order to get a hydrostatic pressure effect, the clearance was set to 0.5% of the thickness of strip, and the counter punch and stripper plate with Vee-ring was set-up. While this experiment was carry8ing out, the average blanking velocity was constant (37.5mm/sec). As a result of this study, we got a good surface roughness and a dimensions, the good squareness and the reduction of dish-shape could be obtained, and also the additional results obtained were such that the hardness of shear plane was increased and the maximum blanking force was reduce in the condition of Vee-ring height of 1.0~1.5mm, and blankholding force of 1200kg.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.123-129
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• 2003

Recently, the life cycle of products is rapidly shortened and then the disposal of the used mold applied in development of the product is a difficult thing. In this study, we proposed the feasibility of new three plate type mold structure for recycling by analyzing of the existing standard mold base. And in order to apply new three plate mold structure in mold design and making. we constructed the specifications for mold parts such as runner stripper plate, cavity plate, core plate and slide core unit. Also, we confirmed the possibility of recycling mold base by testing a used three plate mold for audio front panel.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.114-117
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• 2000

In order to keep the zero defect of production in press working process. The optimum design of the production part, strip process layout, die design, die making and try out etc. are necessary the analysis of effective factors. For example, theory and practice of metal shearing process and it's phenomena, die structure, machine tool working for die making, die materials and it's heat treatment, metal working in field, their know how tc. are included in those factors. In this study, we analyzed whole of data base, theoretical back ground of metal working process, and then performed the progressive die tryout with the screw press. Part 2 of this study reveals with precision progressive die design, its making and tryout.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.598-602
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• 1996

This study is performed for investigating the effects of stripping and counter punching force on shearing characteristics in fine blanking, such as camber, burr-height and dimensional accuracy, etc by experiments. Conventional hydraulic press equipped with specially designed hydraulic unit is used for experiments so that both the stripping force and counter punching force are arbitrarily adjusted according to experimental conditions. Two kinds of materials, hot rolled steel sheet(1mm, 3mm) and pure aluminum(1mm, 3mm) are selected in order to examine the influence of strength and thickness of working materials in blanking of T-shaped products. Based on the experimental results of this study, it can be concluded that the finely cut surface of sheared blank can be obtained even in conventional hydraulic press if additional equipments and special dies are employed.