• 소성∙가공
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• 제14권5호
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• pp.432-438
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• 2005

Among the most of manufacturing process, plastic deformation method offers a significant advantage in productivity and enable mass production with controlled quality and low cost. From the point of view, micro forming is a well suited technology in manufacturing very small metallic parts, in particular for mass production, as they are required in many industrial products. Meanwhile, Al 5083 superplastic alloy with very small grains has a great advantage in achieving micro deformation under low stress due to its relatively low strength at a specific high temperature range. This paper describes the micro formability of Al 5083 superplastic alloy and its application to die forging of micro patterns. Micro formability tests of Al 5083 superplastic alloy were carried out with the specially designed micro forging system by using V-grooved micro dies and pyramidal dies made of (100) silicon. With these dies, micro forging was conducted by varying the applied load, material temperature and forging time The micro formability of Al 5083 superplastic alloy was evaluated by comparing $R_f$ value, where $R_f\;=\;A_f/A_v$ ($A_v$ : cross-sectional area of the flowed metal, $A_v$ : cross sectional area of V-groove). The micro formability of 3 dimensional Patterns was also evaluated using Pyramidal type micro dies.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.54-58
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• 1997

In this study, study, about Automatic Loader and Unloader system which can directly be used for material handing and tool operating is moving linear transfer system for mainly forming of small electronic unit and other at press line. This system for been installed in a press in order to load and unload a workpiece from a press die. Control method be used Programmable logic control(PLC) unit. other Control equipment of system is Motor drive, Positioning Control and so on. It took data of input from each sensor and send signal of output to actuator by sequence program. We try to Characteristics test of this system has good condition when operating by laser measurement

• 한국생산제조학회지
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• 제20권4호
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• pp.446-451
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• 2011

Recent trends for the miniaturization and weight reduction of portable electronic parts have driven uses of subminiature components. Assembly of the miniaturized components requires subminiature screws of which pitch sizes are micrometer scale. To produce such subminiature screws with high precision threads, not only a precision forming technology but also a high-precision measurement technology is required. The present study covers the development of a vision inspection system for precision screws for the automatic measurement of subminiature screws with high speed and reliability. In this study, the feeding unit that transfers the subminiature screws to the inspection unit is investigated through finite element(FE) analysis. The vibration characteristics of the feeding unit are predicted through FE analyses, from which we can determine whether the subminiature screw can be stably fed into the inspection unit or not. The effects of several design parameters on the vibration characteristics are also discussed.

• 한국기계가공학회지
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• 제16권6호
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• pp.133-138
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• 2017

Recently, CFRP composites are widely used as lightweight materials have with excellent mechanical properties and can beare widely used in various fields. In general, thermosetting resins are used for CFRP. However, in recent years, studies have been carried out using thermoplastic resins have been actively carried out to overcome the disadvantages of thermosetting resins. The LFT-D system is a molding method in which a fiber is directly cut to a the desired length while being impregnated with a thermoplastic resin to produce a compound and that is then press-molding molded to form the product. In this paper, before the production of the trailing arm, the compression molding analysis was carried out in order to grasp the problems that may occur during production. Through cCompression molding analysis was applied to calculate of the minimum press pressure and to compare and analysis analyze the molding conditions characteristic required to formfor forming the trailing arm.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.107-112
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• 1997

In this study of made Autmation system is moving linear transfer system for mainly forming of small electronic unit and other at press line. This system for loading and unloading a workpiece has been installed in a press in order to load and unload a workpiece from a press die. Main Control method be used PLC. It took data of input from each sensor and send signal of output to actuator by sequence program also, we try to Characteristics test of this system has good condition when operating with raser measurmant.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.983-987
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• 2001

This paper deals with an automated computer-aided process planning system by which designer can determine operation sequences even if they have little experience in process planning of wheel bolt products by a multi-stage former. The approach to the system is based on knowledge-based rules and a process knowledge base consisting of design rules is built. Knowledge for the system is formulated from plasticity theories, empirical results and the empirical knowledge of field experts. Programs for the system have been written in AutoLISP for the AutoCAD using a personal computer and are composed of two main modules. An attempt is made to link programs incorporationg a number of expert design rules to form a useful package. Results obtained using the modules enable the designer and manufacturer of wheel bolt product to be more efficient in this field.

• 한국세라믹학회지
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• 제39권5호
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• pp.460-466
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• 2002

티타늄 임플란트의 표면을 열산화법을 이용하여 티타늄의 표면 위에 생체활성을 갖는 $TiO_2$ 박막을 생성시켜 다양한 의료분야의 응용 가능성을 검토하였다. 시판되고 있는 순수한 티타늄 디스크를 세척 공정을 거친 후, 공기와 아르곤 분위기에서 500, 550, 600, 650, 700${\circ}C$의 온도로 10분간 각각 열산화 처리를 실시하였다. 열처리된 시편의 인산칼슘 결정의 형성 능력을 시험하기 위하여 36.5${\circ}C$의 Eagle's minimum essential medium 용액에서 15일 동안 침적시험을 행하였다. 침적하기 전과 후의 시편의 표면 형상과 표면 조성을 Field Emission-Scanning Electron Microscopy(FE-SEM)와 Energy Dispersive X-ray Spectrometry(EDS)로 각각 분석하였다. In vitro 시험에서 미세한 $TiO_2$ 결정이 생성된 박막의 표면에는 탄소가 함유된 인산칼슘 결정이 생성됨을 확인하였다.

• 한국표면공학회지
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• 제51권1호
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• pp.40-46
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• 2018

The light-weight of the research and development materials is actively carried out by overseas automobile companies and technology development continues in Korea. For the sake of fuel efficiency, the development of lightweight technology by improving the manufacturing method has been very effective. Recently, to maximize the effects of light weight, automotive interior parts have been applied by the micro-cellular injection molding using supercritical fluids and we call the Mucell manufacturing. This technique causes a problem in the quality of the surface of the products, because the shooting cells are revealed as the surface layer of the products by forming micro cells at the center of the products during injection molding. To overcome these phenomenon, we increased the temperature of injection molding using joule heating until critical value. In this study, we have predicted the problem of Mucell injection molding through the finite element analysis as changed the temperature by joule heating. From the result of finite element analysis, we have determined the optimized process and made the injection mold included electric current heating system with Mucell manufacturing analyzed the surface characteristics of the injection product according to changing mold temperature.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.71-74
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• 2005

In manufacturing automotive parts, such as engine cradles, frame rails, subframes, cross-members, and other parts from circular tubes, pre-bending and pre-forming operations are often required prior to the subsequent tubular hydroforming process. During some pre-forming operations, the cross section of a bent circular tube is crushed into an oval-like shape to ensure proper geometry and sufficient clearance in the hydroforming dies. For such applications, the use of oval Instead of circular tubes could be an effective means of eliminating the pre-forming step. The oval tube could also be produced with less thinning and with less strain on the outside of the bend when controlled by a booster system without the use of mandrel. Hence, the understanding of the issues that occur in the bending of oval tubes is worthy of Investigation. This paper presents parametric studies on the bending of oval tubes without a mandrel. The finite element modeling technique is used to examine the deformation characteristics for both circular and oval tubes. In the simulations, the bending process parameters of bend radius, aspect ratio of the tube ovalness, and tube wall thickness are varied. Observations are made to obtain a hoop-buckle limit diagram in terms of a non-dimensional shape degradation factor. Suggestions based upon developed criteria are made on the acceptability of bend tubes suitable for hydroforming applications without the need ofa pre-forming step or the used of a mandrel.

• 한국기계가공학회지
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• 제11권6호
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• pp.152-157
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• 2012

This study investigates compressive strength of ice pellet strip which is potential medium for Natural Gas Hydrate(NGH) extruded from die holes of Twin-roll Press for Continuous Pelletizing(TPCP). Recently, the prototype of TPCP is newly developed where ice powder is continuously fed and extruded into strip-type pellet between twin rolls. The system is specifically designed for future expansion towards mass-production of ice pellet strips or solid form of natural gas hydrate. It is shown that the compressive strength of pellet strip heavily depends on factors in extrusion process such as disk size, surface smoothness, ring size, taper shape, feeding mechanism, and rotational speed. Here, the mechanism of TPCP, along with compressive strength of pellets is discussed in terms of its feasibility for producing NGH pellets in the future.