• 한국주조공학회지
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• 제18권3호
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• pp.246-253
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• 1998

Precision metal mold casting process is a casting method manufacturing mechanical elements with high precision, having heavy/light alloys as casting materials and using permanent mold. To improve dimensional accuracy and the final mechanical properties of the castings, the solidification speed and the cooling rate of the casting should be controlled with the optimum mold cooling system, and moreover, to obtain more accurate control of the whole process interfacial heat transfer characteristic at the mold/casting interface must be studied in advance. In the present study, aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling system was designed and the temperature histories at points inside the metal mold were measured during the casting process. The heat transfer phenomena at the mold/casting interface was characterized by the heat flux between solidifying casting metal and metal mold, and the heat flux history was obtained using inverse heat conduction method. The effect of mold cooling condition upon the heat flux profile was examined, and the analysis shows that the heat flux value has its maximum at the beginning of the process.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.181-182
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• 2015

The production technologies of free-form concrete panels are emerging to satisfy the need of modern complex shaped in architectural design. This study aims for introducing and improvising the innovative technique called Rod type mold that overcomes the difficulties in some extent by enabling the mold to be used many times, making the shape of the mold adjustable in a flexible way and describing its production process to provide the alternative solution for the construction of free-form mold with considering the features including reusability and optimization cost across its production process. In this study, the freeform concrete panel shape was designed and experiment was done using computerized numeric control machine and rod type mold. The problems appeared on achieving desired shape while operating on rod type mold. The process of identifying all the root causes and contributing causes that may have generated an undesirable condition were done. Consequently, the conical or semicircular shaped was proposed for the end of Numerical control rod and replaced it with the existing flat shaped end to avoid the detachable problem and to improve rod type mold performance.

• 소성∙가공
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• 제20권1호
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• pp.29-35
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• 2011

In the design of the injection molding process, various parameters including mold design parameters and molding conditions should be investigated to improve part quality. The mold temperature is one of important processing parameters that affect the flow characteristics, surface appearance, part deformation, mechanical properties, etc. Numerical analyses have been used to predict the temperature distribution of the mold under the given cooling or heating conditions. However, conventional analyses have been performed by assuming that the mold material is a single solid even though a number of plates are assembled to construct an injection mold. In the present study, a numerical approach considering the thermal contact resistance is proposed to provide more reliable prediction of the mold temperature distribution by reflecting the heat-resistance between assembled mold plates.

• 산업공학
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• 제12권3호
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• pp.480-486
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• 1999

Mold base design is one of the most critical steps in production of plastic parts. This paper presents an efficient method for generating a 3D CAD library for injection mold base and mold components. In this paper, a new description language (DL)formats are proposed. These DL formats can represent the geometric feature, the variable dimensions and the assembly structures of mold base and its components. And the processes of adding the mold components and creating the mold assemblies can be performed very easily and efficiently by using DL scripts. Proposed method has been tested by implementation of 3D library with DL scripts and DL-interpreter with C language. The DL and interpreter are independent of CAD system. They were applied to the automatic mold base designing system which works on Unigraphics V15. The system is developed with UG API function under Windows-NT environment.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.397-402
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• 2000

In this paper, we have been concerned with development of plastic mold design system by using Auto CAD. We provides a interface and interaction for mold designer who can select optimal mold base and mold parts within Auto CAD environment. We use the paramatric design method and an essential elements group forms. This program made for using Visual Lisp, DCL and Visual Basic that could easily get a database which is built to mold base and parts within Auto CAD. We provide 6 types mold base and 35 parts database for designer. In addition, it will be lined to mold cost and not only 2-D but also 3-D models

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2006년도 추계학술발표대회 논문집
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• pp.96-102
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• 2006

In this study, manufacturing of polymer master, PDMS(poly dimethylsiloxane) transfer mold, and mold insert was investigated for laser LIGA(LIthography Calvanoformung Abformtechnik). Initially, ablation by excimer laser radiation was used successfully to make 3-D microstructure of PET. After then, the PDMS transfer mold was replicated using ablated PET. Finally, epoxy resin tooling on replicated PDMS transfer mold was executed for making mold insert. From these facts we can conclude that excimer laser ablation of polymer and fabricaiton of PDMS transfer mold are reasonable tools to substitute for X-ray lithography of LIGA process in microstructuring.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.159-162
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• 2008

High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

• 한국주조공학회지
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• 제24권1호
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• pp.26-33
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• 2004

The pressure of the mold flux acting on the meniscus shell was investigated through the coupling analysis of heat transfer in the mold and fluid flow in the flux caused by the mold oscillation. Finite element method was employed to solve the conservation equation associated with appropriate boundary conditions. As reported by previous workers, the axial pressure is positive on the negative strip time and negative on the positive strip time. A maximum pressure is predicted toward the top of the meniscus shell which has the thin shell arid a maximum value is in proportion to the relative mold oscillation velocity. The relative mold oscillation velocity was changed by the effect of meniscus level fluctuation. Therefore the pressure of the mold flux acting on the meniscus shell was different each cycle of the mold oscillation due to the irregularity of relative mold oscillation velocity.

• 한국정밀공학회지
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• 제21권6호
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• pp.117-121
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• 2004

Injection molding is the one of the most important processes for mass production of plastic parts. Usually injection molds for mass production are constituted to multi-cavity runner system to manufacture the more parts at a time. Multi-cavity molds are designed to geometrically balanced runner system to uniformly fill to each cavity. But, when injection molding is performed using a mold with balanced runner system filling imbalances are occurred between the cavity to cavity. The previous studies by Beaumont at. all reported that filling imbalance occurred by thermal unbalance on the mold and viscosity variation of resins and so on. In this study, we conducted experiments in order to know the causes of filling imbalance for 3 plate type mold with 8 cavities. And we exhibited a new so called 4BF mold (4 plate type Balanced Filling Mold) to be possible filling balance. We conducted a experimental injection molding to verify the efficiency of the 4BF mold. In the results of the experiment, we could confirmed the balanced filling possibility of the 4BF mold.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.149-153
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• 2008

The cavity of mold is exposed to high pressure during injection molding operation. Injection molded articles with deep depth are often demanded as design variety increases. Mold becomes weak and deformation increases as the mold depth increases. Thus the injection molds for deep depth articles should be designed to hold out high pressure or stress and large deformation. Through this study, equation for mold design was examined and suggested novel method to determine equation for mold design with deep depth. Novel equation developed in this study was consisted with cantilever and two points bending while previous equation was modified from just cantilever bending. The validity of novel equation was verified through computer simulation.