• 한국주조공학회지
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• 제13권1호
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• pp.81-93
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• 1993

It is well-known that the analysis of elasto-plastic thermal stress and deformation are substantially important in optimal design of metal casting mould. The unsteady state thermal stress and deformation generated during the solidification process of ingot and mould have been analyzed by two dimensional thermal elasto-plastic theories. Distributions of temperature, stress and relative displacement of the mould are calculated by the finite element method and compared with experimental results. In the elasto-plastic thermal stress analysis, compressive stress occurred at the inside wall of the mould whereas tensile stress occurred at outside wall. A coincidence between the analytical and experimental results is found to be fairly good, showing that the proposed analytical method is reliable.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1831-1841
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• 2002

The effect of a rubber mould on densification and deformation of aluminum alloy powder was investigated during warm isostatic pressing. The hyperelastic constitutive equations based on various strain energy potentials were employed to analyze deformation of rubber. The parameters in the strain energy potentials were obtained from experimental data for uniaxial and volumetric compression of Viton rubber at two warm temperatures. For elastoplastic response, the yield function of Shima and Oyane was implemented into a finite element program (ABAQUS) to predict compaction responses of metal powder during warm isostatic pressing. Finite element results were compared with experimental data for densification and deformation of aluminum alloy powder with/without a rubber mould under warm die pressing.

• 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.

• 대한기계학회논문집A
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• 제27권7호
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• pp.1076-1086
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• 2003

The effect of a rubber mould on densification behavior of aluminum alloy powder was investigated under cold isostatic compaction. A thickness of rubber mould and friction effect between die wall and rubber mould were also studied. The hyperelastic constitutive equation based on the Ogden strain energy potential was employed to analyze deformation of rubber. The elastoplastic constitutive equation of Shima and Oyane and that of Lee on densification were implemented into a finite element program (ABAQUS) to simulate densification of metal powder for cold isostatic pressing and rubber isostatic pressing. Finite element results were compared with experimental data for densification and deformation of aluminum alloy powder under isostatic compaction.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.274-278
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• 2000

Ball end milling process is widely used in the die and mould manufacturing because of suitableness for the machining of free form surface. But, as ball end mill is long and thin, it is easily deflected by cutting force. In this study, Cutting force, tool deflection and surface precision was measured according to the change of depth and cutting location. Cutting force was acquired with tool dynamometer and a couple of eddy-current sensor measured tool deflection in x-y direction each. After machining, surface precision was measured with roundness tester and coordination measuring machine for sculptured surface angle change and cutting depth.

• 대한기계학회논문집A
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• 제20권12호
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• pp.3899-3908
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• 1996

In order to clarify the effects of nonmetallic inclusion contents insteels (SM45C & SCM440) on the tool life, cutting experiment was performed under various cutting conditions. Tool life, cutting force, roughness of machined surface and cutting mechanism are examined on these two kinds of steel. The following conclusions were obtained from the analysis (1) Cutting force of the steels was not affected by chemical component and nonmetallic inclusion. (2) If the rate of amount, Ca/S has a value grater than about 0.2 and addition of less amount of Al, Mn, tool wear of tips decreasesinturning. (3) It is also proved that higher contents of nonmetallic inclusion improve roughness of the surface. (4) Less amount of Ca, higher amount of S, Mn and Al improve the chip breakability.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.359-364
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• 1999

Due to rapid growth of die and mould industries, it is urgently required to maximize the productivity and the efficiency of machining. In recent years, owing to the development of new kinds of material, die and mould materials are much harder and it is more difficult to cut. In this study, the workpiece SKD11(HRC45) is cut with TiAlN coated tungsten-carbide cutting tools. To find the general characteristics of difficult-to-cut materials, orthogonal turning test is performed. Orthogonal cutting theory can be expanded to oblique cutting model. The oblique cutting process in the small cutting edge element has been analyzed as orthogonal cutting process in the plane containing the cutting velocity vector and chip-flow vector. Hence, with the orthogonal cutting data obtained from orthogonal turning test, the cutting forces can be analyzed through oblique cutting model. The simulation results have shown a fairy good agreement with the test results.

• 산업공학
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• 제13권2호
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• pp.246-252
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• 2000

As moulds and dies are manufactured through complex processes under the make-to-order production environment, it is very difficult that the manufacturing activities as like observance of the due date, trace of the progress, etc are controlled with a real time. In this paper, a schedule-planning system using the commercial software Microsoft Project 98 is developed to control the procedures of mould and die manufacturing with real time. Once an initial schedule is planned from the BOM information in the intranet, it is rescheduled by data collected from machines on the shop floor. The system is suitable to medium- or small-sized manufacturing companies as well as large-sized ones, because it can be installed with a low cost.

• Design & Manufacturing
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• 제6권1호
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• pp.45-51
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• 2012

The main goal of this paper is to establish an interference tolerance for determining optimal amount of clearance in the shaft-bearing system supported by radial ball bearings. The 2-D frictional contact model was employed for the FE analysis between the shaft and the inner raceway. Several examples were simulated using different material properties for the solid shaft. Efforts were focused on the deformation applied in the radial direction to select suitable bearings. The analysis results showed that the initial axial preload applied on the bearings plays a significant role to reduce bearing fatigue life. The proposed design parameters obtained by numerical simulations can approximately predict a rate of bearing life reduction as a function of shaft diameter ratio. This analysis can also be used to calculate the optimal initial radial clearance in order to obtain a shaft-bearing system design for high accuracy and long life.

• 한국기계연구소 소보
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• 통권10호
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• pp.27-32
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• 1983