• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.271-271
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1660-1663
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• 2005

Unwanted vibrations are inevitably induced in other directions when pure unidirectional vibration motion is desired for the vertical scratching mechanism. Pure vertical vibration motion of the scratching machine can be obtained by driving identical two motors with symmetrically positioned eccentric unbalance masses. The desired optimal condition for driving pure vertical vibration for the scratching machine is assumed to be the resonance condition in that direction. Imposing the flexibility of the scratching machine in the horizontal direction, we can find out the amount of horizontal vibration component while maintaining the resonance in vertical direction. The desired stiffness in horizontal direction which produces the minimum vibration in horizontal direction are defined which can be used as a guide line to design the supporting structure of the scratching machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.448-451
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• 2003

This study describes a new maskless nano-fabrication technique of Si (100) using the combination of nanometer-scale mechanical forming by nano-indenter XP and KOH wet etching. First the surface of a Si (100) specimen was machined by using the nano-machining system, which utilizes the mechanism of the nano-indenter XP. Next, the specimen was etched by KOH solution. After the etching process, the convex structure or deeper hole is made because of masking or promotion effect of the affected layer generated by nano-machining. On the basis of this interesting fact, some sample structures were fabricated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.147-147
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• 2004

폴리메틸메타크릴레이트(polymethylmethacrylate, PMMA)는 아크릴레이트계 고분자이자 열가소성 플라스틱으로써 LCD용 도광판, 콘택트렌즈, 치과용 레진, DVD 디스크용 소재, 나노임프린트용 피가공재, 나노리소그래피 공정용 레지스트 등 많은 분야에서 활발히 사용되고 있다. PMMA 와 같은 점소성 점탄성 소재의 기계적 성질 측정 및 가공을 위해서는, 응력완화 (stress relaxation), 크립 (creep)등과 같은 시간의존적 변형거동에 대한 연구가 선행되어야 한다.(중략)

• 프린팅코리아
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• v.13 no.8
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• pp.128-131
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• 2014

라미네이팅은 각종 스크래치나 오염으로부터 인쇄물을 보호하고 수명을 연장하는 한편, 컬러를 돋보이게 함으로써 인쇄물의 가치를 높이는 중요한 후가공 공정으로 인정받는다. 특히 미국에서는 일반 상업인쇄물은 물론이고, 옥외광고용 대형 디스플레이까지 활용 범위를 넓혀가며 그 영향력을 확대하고 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.628-631
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• 2003

This study describes a new mastless nano-fabrication technique of Pyrex 7740 glass using the combination of nanomachining by nano-indenter XP and HF wet etching. First, the surface of a Pyrex 7740 glass specimen was machined by using the nano-machining system, which utilizes the mechanism of the nano-indenter XP. Next, the specimen was etched by HF solution. After the etching process, the convex structure or deeper hole is made because of masking or promotion effect of the affected layer generated by nano-machining. On the basis of this interesting fact. some sample structures were fabricated.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.24-31
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• 2004

Masking effect of the nanoscratched silicon (100) surface was studied and applied to a maskless nanofabrication technique. First, the surface of the silicon (100) was machined by ductile-regime nanomachining process using the scratch option of the Nanoindenter${ \circledR}$ XP. To clarify the possibility of the nanoscratched silicon surfaces for the application to wet etching mask, the etching characteristic with a KOH solution was evaluated at room temperature. After the etching process, the convex nanostructures were made due to the masking effect of the mechanically affected layer. Moreover, the height and the width of convex structures were controlled with varying normal loads during nanoscratch.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.134-140
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• 2002

Chemical mechanical polishing of aluminum and photoresist using colloidal silica-based slurry was experimented. The effects of slurry pH, silica concentration, and oxidizer ($H_2O_2$) concentration on surface roughness and removal rate were studied. The optimum slurry conditions for reduction of micro-scratch were investigated. The optimum chemical mechanical polishing with the colloidal silica-based slurry was compared with conventional chemical mechanical polishing with alumina-based slurry. Chemical mechanical polishing of the aluminum with the colloidal silica-based slurry showed improved result but chemical mechanical polishing of the photoresist did not. The improved result was comparative with that of chemical mechanical polishing with filtered alumina-based slurry which one of desirable methods to reduce the micro-scratch.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.363-366
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• 2003

In nanomachining processes, chemical effects are more dominant factor compared with physical deformation. For example, during the nanoscratch on a silicon surface in the atmosphere, micro protuberances are formed due to the mechanochemical reaction between the diamond tip and the surface. On the contrary, in case of chemically stable materials, such as ceramics or glasse, the surface protuberance are not formed. The purpose of this study is to understand effects of the mechanochemical reaction between tip and surfaces on deformation behaviors of hard-brittle materials. Nanometerscale elasoplastic deformation behavior of single crystal silicon (100) was characterized with the surface protuberance phenomena, and compared with that of borosilicate (Pyrex glass 7740).

• Transactions of Materials Processing
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• v.22 no.2
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• pp.86-92
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• 2013

When stamping ultra-high-strength steel (UHSS), the phenomenon of galling, which corresponds to a transfer of material from the sheet to the tool surface, occurs because of the high contact pressure between tool and workpiece. Galling leads to increased friction, unstable interface conditions, scratches on the sheet and the tool surfaces and, eventually, premature tool surface failures. Therefore, a simple and accurate evaluation method for tool scratching is necessary for the selection of tool material and coating, as well as for a better optimization of process conditions such as blank holder force and die radius. In this study, the pin-on-disc (PODT) and pin-on-flat surface (POFST) tests are conducted to quantitatively evaluate scratch-related tool life for stamping of UHSS. The variation of the friction coefficient is used as an indicator of scratch resulted from galling. The U-channel ironing test (UCIT) is performed in order to validate the results of the friction tests. This study shows that the POFST test provides a good quantitative estimation of tool life based on the occurrence of scratch.