• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.61-70
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• 2004

Generally, ceramics are very difficult-to-cut materials because of its high strength and hardness. The machining process of ceramics can be characterized by cracking and brittle fracture. In the machining of ceramics, edge chipping and crack propagation are the principal reasons to cause surface integrity deterioration. Such phenomenon can cause not only poor dimensional and geometric accuracy, but also possible failure of the ceramic parts. Ceramics can be machined with traditional method such as grinding and polishing. However, such processes are generally cost-expensive and have low material removal rate. Thus, in this paper, to overcome these problems. BN powder, which gives good cutting property, is added for the fabrication of machinable ceramics by volume of 5,10,15,20,25 and 30%. And, mechanical properties, R-curve behavior and machining tests are carried out to evaluate the machining properties of the manufactured machinable ceramics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.882-885
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• 2002

Magnesium alloys are very attractive materials for appling to the development of autemobile parts or electric goods where light weight and higher stiffness. Due to higher ratio of strength vs. weight and stillness vs. weight, various magnesium alloys are well applied in much weight saving design applications though extrusion or die-casting process. However for the requisites of higher strength and weight savings, some new fabrication processes has been and it can be realized though the aid of injection modeling technology. To obtain the parametric data base for the injection molding process, various experiments were executed for AZ91D magnesium alloy. This paper propose the optimum condition of injection temperature, first and second pressure. the process was lined-up successfully often changing the injection unit. fluid pressure system from the conventional plastic injection molding process.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.106-113
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• 2000

One of the recent changes in machining technology is rapid application of micro- and high precision grinding processes. A fine groove generation is necessary for the fabrication of optics, electronics and semiconductor parts. Slot grinding is very efficient for the generation of micro ordered groove with hard and brittle materials. In the process of slot grinding, chipping at the sharp edges and microcracks of the ground grooves are inevitable defects. Chipping should be reduced for the improvement of surface integrity. Mechanical contact with diamond grits causes microcracks at the grooves. This damage resides subsurface, and can be the cause of failure of the punch die. This paper deals with chipping generation at the sharp edges, surface integrity of side groove and fracture strength is related to the microcracks in the slot grinding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.925-928
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• 2004

The application of focused ion beam (FIB) technology in micro/nano machining has become increasingly popular. Its use in micro/nano machining has advantages over contemporary photolithography or other micro/nano machining technologies such as small feature resolution, the ability to process without masks and being accommodating for a variety of materials and geometries. This paper was carried out some experiments and verifications of mechanism on FIB-CVD using SMI8800 made by Seiko. FIB-CVD has in fact proved to be commercially useful for repair processes because the beam can be focused down to 0.05$\mu\textrm{m}$ dimensions and below and because the same tool can be used to sputter off material with sub-micrometer precision simply by turning off the gas ambient. Recently the chemical vapour deposition induced ion beam has been required more deposition rate and accurate pattern because of trying to manufacture many micro and nano parts. Therefore this paper suggested the optimization parameters and discussed some mechanism of chemical vapour deposition induced ion beam on FIB-CVD for simple pattern.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.185-190
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• 2010

Application of CAE analyses are wide spread in shaping processes and structural safety verification of plastic products. The importance of CAE analysis and its contributions are getting increase since the processibility and structural safety of product can be predicted. CAE analysis for complex shaped product need a lot of time for modeling and computation compare with simpler one. Therefore careful simulation modeling is required for complex shaped product. Structural analysis for plastic door handle of automobile has been performed and structural safety has been investigated for various load directions and modeling cases. Large stress occurred at the hinge in handle regardless of load direction and modeling case. Consequently hinge is considered structurally very weak among the parts in plastic door handle. It is concluded that simple modeling rather than total modeling with adequate boundary condition equivalent to real situation gives reasonable computational results with saving modeling effort and computation time.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.2
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• pp.61-71
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• 2006

The purpose of this study is to present a contents production process for costume design analysis by take advantage of the image media of Chinese historical backgrounds. The production process of contents for lectures on fashion design analysis can be summarized as follows: The contents for the design analysis of Chinese costumes can be divided into major media and supplementary media. Major media can be completed through the processes including the selection of Chinese historical backgrounds. images and media (video, DVD title or VOD), verification of image capture parts, image captures, and applications of PPT files. Supplementary media consist of production of analysis materials for each item and TPO, report preparation methods and discussions, and printed matters to be used at the stage of image comparison and verification. This way, a process applicable to the design analysis of Chinese costumes can be presented.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.221-227
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• 2003

Heat treatment is widely used in various manufacturing Processes to enhance the quality of a Product such as strength, surface hardness, and service life. In the heat treatment, there is dimensional change or distortion of the product, which critically influences the dimensional accuracy of precision parts. In this study, the distortion of a straight bevel gear induced by heat treatment is investigated in two cases. In the first case, the distortion induced by heat treatment we compared between a forged bevel gear and a machined bevel gear. In the second case, the distortion of an annealed gen is compared with that of a quenched gear. And finite element analysis has been Performed to predict the distortion of a heat-treated and machined bevel gear. The predicted values are compared with the experimental values.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.265-268
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• 2006

The superplastic forming/diffusion bonding is widely accepted as an advanced technique for forming complex industrial components. But the superplastic forming process requires much forming time and generates excessive thinning thickness distribution of formed part. Superplastic in materials is only achieved in a narrow range of strain-rate with optimum value unique to each material. In this study, finite element analysis for surperplastic forming/diffusion bonding (SPF/DB) processes of three-sheet and four-sheet sandwich parts. From this study, forming analysis have offered a lot of information for developing the forming process.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.107-112
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• 2012

Gas-assisted injection molding(GAIM) produces parts with hollow internal sections. The technique offers benefits to powder injection molding(PIM), with lower material usage and reduced time for de-binding processes. In this study, the effects of processing parameters on gas penetration length of gas-assisted powder injection molding(GAPIM) were investigated for SUS316L stainless steel powder feedstock. Experiments were planned based on the Taguchi method, involving processing variables such as melt temperature, shot size, gas pressure, and gas delay time. The most significant parameters affecting gas penetration length were gas delay time and shot size, while the effects of melt temperature and gas pressure was relatively insignificant.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.1-8
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• 2015

Recently, a great interest in 3D printing has emerged, although many existing 3D printing technologies were first developed 2-3 decades ago. There are many mature 3D printing processes and materials; however, active research and development efforts are ongoing in this area to advance the technologies. Several companies have already started to use 3D printed parts as actual components. Many low-cost 3D printers have been released on the market, which are of particular interest to educators and hobbyists. This paper provides a brief review of 3D printing technologies and research trends. In addition, several state-of-the-art technologies and applications are introduced.