• 연구논문집
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• s.28
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• pp.59-71
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• 1998

The ELID(electrolytic in-process dressing) grinding method is a new precision grinding technique with the special electrolytic in-process dressing by metal bonded grinding wheel, fluid, and power supply. It is possible to make a efficient precision machining of hard and brittle materials such as ceramics, hard metals, and quenched steels by using this method, In this study, a new efficient precision grinding method with ELID was attempted for application to the machining and finishing processes of cylindrical structural components. And, we try to develop the cylindrical grinding technique for mirror surface of ceramics, tungsten carbide and SCM steel, and for the high efficiency grinding of machined parts, for example, ball screw shaft. Electrical characteristics of three different wheel grit sizes of #325, #2000 and #4000 were investigated experimentally. ELID grinding method is proved to be useful for mirror surface generation and efficient machining.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.177-183
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• 1994

The ball-end milling process is widely used in the die/mold industries, and it is very suitable for the machining of free-from surfaces. However, cusps(or scallops) remaining at the machined part along the cutter paths require anothe finish process such as polishing or grinding. In this study, a high sped micro ball-end milling method has been suggested for the finish of free- form surfaces. A new tool path which makes the geometrical roughness of workpiece be constant through the machined surface has been developed. In the high speed machining of micro ball-end muling experimets, the developed tool paths have been successfully applied. And it was concluded that the surface roughness from this finish cuts of micro ball-end milling process was acceptable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1522-1526
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• 2005

In this study, the fabrication of large area silicon mirror is accomplished by anisotropic etching using MEMS for implementation of integrated optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafer using wet etching. In addition rough surface of the mirror is achieved in case of long etching time. Hence a novel method called magnetorheolocal finishing is introduced to enhancing the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.28-41
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• 1994

An efficient algorithm is proposed to select the proper tools and generate their paths for NC rough cutting of dies and molds with sculptured surfaces. Even though a milling process consists of roughing, semi-finishing, and finishing, most material is removed by a rough cutting process. Therfore it can be said that the rough cutting process occupy an important portion of the NC milling process, and accordingly, an efficient rough cutting method contributes to an efficient milling process. In order work, the following basic assumption is accepted for the efficient machining. That is, to machine a region bounded by a profile, larger tools should be used in the far inside and the region adjacent to relatively simple portion of the boundary while smaller tools are used in the regions adjacent to the relatively complex protion. Thus the tools are selected based on the complexity of the boundary profile adjacent to the region to be machined. An index called cutting path ratio is proposed in this work as a measure of the relative complexity of the profile with respect to a tool diameter. Once the tools are selected, their tool paths are calculated starting from the largest to the smallest tool.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.190-193
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• 1990

Die finishing (polishing and lapping) after NC machining is characterized as one bottleneck process for reducing lead time. For automation of this typical manual work, a flexible polishing tool system using industrial robot has been developed. This tool system has three principal functions in order to achieve reduction of waviness, 3 D.O.F. compliance and constant pressure structure. This polishing tool shows that adaptability to free form surface is increased and programmability to various areas of die surface is also acquired.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.674-675
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• 2016

In this paper, we propose a manufacturing process model of Internet of Things devices using a Printed Circuit Board (PCB)-mounted RFID tag chip for reducing electronic wastes. Electrical and electronic products require a PCB surface mount and many examination. Also, conventional barcode systems cannot provide traceability management in PCB manufacturing before finishing Surface Mount Technology (SMT) process. The proposed process model does not require workers' attaching and detaching process unlike barcode systems. Also, RFID tag chip can record all the data in manufacturing steps. Thus, the number of connections to a database management system (DBMS) can be reduced.

• Textile Coloration and Finishing
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• v.12 no.6
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• pp.361-371
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• 2000

The problematic effects of fly creation on circular knitting machines during the knitting process were investigated in order to develop a new method for tackling the problem. A new idea, i.e. coating the yarn surface with a polymer film, was studied. Important physical properties of the coated yarm were studied and compared with normal yarn. A new test-rig was designed to measure the coefficient of friction and the degree of shedding of yarn. Yarns were coated with seven polymer materials and the performance of the coated yarns was tested and the results are discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.78-83
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• 2009

In general, Light-hardening polymer was used UV nanoimprint technology. A light-hardening polymer was had the problem of poor hardness, durability. In order to overcome the problem of polymer, inter change optical glass. However glass is very manufacture and a lowering of standars transmittance. In order to glass recover was necessary polishing process. The process is magnetorheological fluids polishing. MR polishing has been developed as a new precision finishing technique to obtain a fine surface. Hence, Magnetorheological fluids has been used for micro polishing to get micro parts. This polishing process guarantees high polishing quality by controlling the fluid density electrically. The applied material in experiments is fused silica glass. Fused silica glass is widely used in the optical field because of high degree of purity. For MR polishing experiments, MR fluid was composed with DI-water, carbonyl iron and nano slurry ceria. The wheel speed and electric current were chosen as the variables for analyzing the characteristics of MR polishing process. Outstanding surface roughness of Ra=1.58nm was obtained on the fused silica glass specimen. And originally glass transmittance was recover on the fused silica glass.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.196-203
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• 2004

SL(Stereolithography) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. The effect brings about excessive surface roughness and cuts down the merits of using SL part. Hence, additional post-machining finishing such as traditional grinding is required. But the traditional post-machining is detrimental to part geometry and time consuming. In this study, therefore, a paraffin coating and grinding post-machining is newly proposed to improve the surface quality of SL fart. The paraffin which has suitable properties for the proposed post-machining is coated all over the part surface. By grinding the only over-coated paraffin based on boundary of the SL part surface, the surface roughness can be improved without any damage on the part. Also, it is verified that SL part finished by the proposed post-machining process can be applied for rapid tooling as pattern through manufacturing silicon rubber molding and casting test.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.138-143
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• 2000

The establishment of a practical ultra-precision grinding technique using Diamond and CBN wheels is one of the major key technolo-gies to improve production techniques for machine-to-difficult materials without finishing process such as lapping and polishing. But the special efficient dressing technique for ultra-fine grit type grinding wheels to stabilize the grinding ability was not developed. Recently electrolytic in-process dressing technique is proposed to ultra-fine grit type metal bonded diamond wheels to protrude abra-sives continuously from the tool surface. This technology can be widely used to surface grinding and cylindrical grinding but cannot be used efficiently to internal grinding because of the electrode attachment trouble. This paper describes the effect of interval type electrolytic dressing as proposed newly to cast iron bonded diamond wheel for efficient internal grinding with mirror type high quality ground surface.