• Design & Manufacturing
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• 제8권2호
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• pp.50-55
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• 2014

Recently, semi-stack mold have been developed for satisfying the various elements required in the mold industry. The mold is possible using with general-purpose injection molding machine by weight reduction through the improvement of the mold structure. In order to do that, tension core, spiral cooling system and half runner system were applied. It is effective for increased productivity and decreased of loss to the materials. However, the mold is required the filling balance in order to improve the quality and efficiency. Thus this study performed that optimum design and analysis of semi-stack mold for filling balance.

• 산업공학
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• 제25권1호
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• pp.52-63
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• 2012

Up-to-date enlargement of the scale of global outsourcing has brought about the need of systematic and efficient tools for competitive supplier discovery located in various areas. A web-based business supporting system, referred to as Excellent Manufacturer Scouting System(EMSS), is being developed to serve core business functions including supplier discovery, negotiation, and collaboration between overseas buyers and domestic suppliers throughout the process of supply chain formation. In this paper, a supplier assessment model devoted to evaluation of core manufacturing capability is proposed by targeting small and medium sized mold companies. The assessment model will eventually be loaded to EMSS. Even if many well-designed models for supplier assessment have been presented in literature, most of them limit the evaluation criteria to somewhat general information on a given supplier, such as cost, delivery time, quality, rather than core manufacturing capability itself. This research is pioneering work on supplier assessment from the viewpoint of manufacturability. The proposed assessment model classifies assessment indices into six criteria, which have been drawn by intensive survey and analysis of the mold industry. Actual assessment indices for each criterion are also presented along with an exemplary evaluation result.

• 한국정밀공학회지
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• 제25권12호
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• pp.39-46
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• 2008

Asymmetric glass lens core for portable projection optic system was designed and simulated. And it was machined by newly developed non-rotational ultra precision grinding method. With the designed lens data which optimized for multi-collimation, we generated the we core surface data. Mold pressing conditions analyzed by FEM. In the machining process, ground profile errors were compensated based on measured data, minimized feed rate and depth of cut. The deviations of machined core profile were acceptable level for glass mold press. Mold pressed glass array lens was coated with $SiO_2\;and\;Ta_2O_5$ for anti-reflection.

• Design & Manufacturing
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• 제6권2호
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• pp.64-69
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• 2012

This study looks at plastic mold design for robots and mold manufacture, which is an injection mold branch at The Korea-China-Japan University Grand Prize Contest. Product analysis and layout, molding analysis, and upper and lower core design are carried out to design molds in 2D and 3D. After the design of the cores, NC machining software is used for simulation before actual manufacture. Before the production of end-product, test injection is done to troubleshoot problems like bad dimensions, burr, cracks and stepped pulley.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1630-1635
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• 2005

The microstructure of the parts made by the microcellular injection molding process influence properties, including impact strength, tensile strength and density of material. Microstructure of microcellular plastics is divided into core foaming region and solid skin region. Core foaming region is influenced by pressure drop rate, viscosity and cell coalescence. However, actual mechanism of the skin layers is not known despite its importance. The study on the skin layer is getting important because foaming rate of the plastics is determined by the thickness ratio of the skin layer. Especially in case of large molded part, control of the skin layer is needed because skin layer thickness is changed largely. Therefore it is necessary to study variation in skin layer thickness with processing parameters. In this paper, the influence of temperatures in the mold cavity on the skin layer s thickness was also addressed. In addition, the relationship between the temperature distributions across cavity of the mold with impact strength on parts made with the microcellular injection molding process was addressed. In addition, the method to predict the variation in skin layer thickness with mold temperature is discussed.

• 한국산학기술학회논문지
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• 제10권1호
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• pp.186-193
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• 2009

본 논문에서는 전열(마이크로 히터, 센서)을 이용해 금형의 표면을 가열하는 E-MOLD 특허기술을 적용하여 휴대전화용 복합기능 도광판(Prismless LGP)을 제작하고, 전사성을 평가하였다. 이를 위하여 MEMS 공정을 이용하여 복합기능 도광판용 니켈 스탬퍼를 제작하였고, E-MOLD 기술의 핵심인 이동가열코어(movable heated core)가 설치된 금형을 설계, 제작하였다 이를 이용하여 성형조건 중 금형온도를 변화시키면서 복합기능 도광판을 사출성형으로 제조 하였고, 금형온도가 성형품의 전사성에 미치는 영향에 대하여 알아보았다. 또한, 전산모사 프로그램(CAE)을 이용하여 금형온도와 사출시간에 따른 수지의 유동성을 해석하였다. 금형온도에 따른 도광판의 전사성은 $100^{\circ}C$(25.0nm), $140^{\circ}C$(48.4nm), $180^{\circ}C$(52.1nm)로 나타났고, 스탬퍼(52.1nm)와 비교했을 때 $180^{\circ}C$에서 전사성이 가장 우수했다. 전산모사 해석결과에 따르면, 수지의 유동성은 금형온도($50{\sim}180^{\circ}C$)가 증가할수록 향상되었다. 사출시($1{\sim}2sec$)이 길수록 유동성이 감소하는 경향을 $160^{\circ}C$에서 확인하였다. 따라서 수지의 전사성과 유동성은 금형온도에 따라 증가하고, 특히 유리전이 온도($140^{\circ}C$) 이상에서 크게 상승하였다.

• 한국안광학회지
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• 제12권4호
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• pp.87-90
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• 2007

polycarbonate(PC)용 안경렌즈를 생산하는데 사용되는 몰드(mold)를 가공하기 위해서는 코아(core)의 가공이 필요하다. 코아의 가공은 Diamond Turning Machine(DTM) 또는 Computer Numerical Control(CNC) 선반으로 이루어지는데 이러한 장비의 운용을 위해서는 렌즈 코아 형상에 대한 수치 데이터가 필요하게 된다. 이에 우리는 렌즈 코아 형상에 대한 수치 데이터를 산출하는 프로그램을 개발하였다. 프로그램은 일반 비구면 식의 계수를 사용하여 수치 데이터를 산출할 수 있도록 개발하였으며, 형상 그래프를 보여줄 수 있도록 하였고, 필요한 수치 데이터 파일을 저장할 수 있도록 하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.270-274
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• 2005

The capability of net shaping for complex 3-D geometry, powder injection molding(PIM) is widely used for parts in the field of automotives, electronics and medical industry. Powder injection mold design for dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip. Product design and mold design for dental scaler tip was presented. Short shot experiment with scaler tip PIM mold and several defect (flash etc.) during injection molding process was discussed.

• 한국기계가공학회지
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• 제18권3호
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• pp.82-87
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• 2019

Recently, plastic materials have become more diversified, and the development of materials with excellent mechanical properties and plasticity has enabled wider application, miniaturization, and refinement of injection molded products. As a result, the utilization of these products in household goods, electronics, automotive parts, and aircraft parts is increasing in almost all industries. Injection molded parts are often used externally on finished commercial products. This means that the injection mold industry is very important to the value of these products. For this reason, the industry is performing research on the precision and efficiency of the injection molding process. In this study, we investigated the applicability of the core in core cooling method to the problem of product deformation due to temperature variation in existing injection mold designs. We also characterized the cooling performance of an injection mold when using this cooling method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.623-624
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• 2005

Micro injection molding is a branch of micro system technology and has been under development for the mass manufacture of micro parts. Enhanced technological products like micro optical devices are entering the market. This paper presents fundamental research on the injection molding technique in micro fabrication. In order to successful manufacturing of micro plastic parts, it is necessary to research for development of micro-injection machine, machining of micro mold, decision of optimum injection conditions and the research for polymer material. Therefore in this study, in order to machining of micro mold, a mold core with microscopic V-shaped groove was tooled by ultra-precise tooling machine. The transcription experiments with a polymer, PMMA resin on the surface of core with Ni plating were carried out and surface profile of injected parts was measured with AFM.