• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.38-43
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• 2007

This paper describes ultrasonically assisted grinding used to obtain a glossy surface quickly and precisely. High-quality surfaces are required for plastic injection molding dies used in the production of plastic parts such as dials for cellular phones. Traditionally, in order to finish the dies, manual polishing by a skilled worker has been required after the machining processes, such as electro discharge machining (EDM), which leaves an affected layer, and milling, which leaves tooling marks. However, manual polishing causes detrimental geometrical deviations of the die and consumes several days to finish a die surface. Therefore, a machining process for finishing dies without manual polishing to improve the surface roughness and form accuracy would be extremely valuable. In this study, a 3D positioning machine equipped with an ultrasonic spindle was used to conduct grinding experiments. An electroplated diamond tool was used for these experiments. Generally, diamond tools cannot grind steel because of excessive wear as a result of carbon atoms diffusing into bulk steel and chips. However, ultrasonically assisted grinding can achieve a fine surface (roughness Rz of $0.4{\mu}m$) on die steel without severe tool wear. The final aim of this study is to realize mirror surface grinding for injection molding dies without manual polishing. To do this, it is necessary to fabricate an electroplated diamond tool with high form accuracy and low run-out. This paper describes a tool-making method for high precision grinding and the grinding performance of a self-electroplated tool. The ground surface textures, tool performance and tool life were investigated A ground surface roughness Rz of 0.14 um was achieved Our results show that the spindle speed, feed rate and cross feed affected the surface texture. One tool could finish $5000mm^2$ of die steel surface without any deterioration of the ground surface roughness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.309-314
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• 2004

0.5mm thick steel is used to manufacture nail files. The first process is blanking and the second process is making about 300 holes of 0.8-l.0mm in diameter. This process depends mainly on etching which takes 33% of manufacturing cost and it can make manufacturing cost rise. The residual etching reagent is not environmentally friendly and the steel material is apt to rust as well. To solve these problems, researches on the following subjects are performed: proper material to prevent from rusting and strip layout strategies in stamping to replace etching process with press process which makes use of die. And new quill type punch is developed to replace the regular standard punch, one of the die parts, which frequently get broken while working. And these researches and developments lead to develop a progressive perforating die.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.452-457
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• 2000

The object of this study is to develop a reliable FEM simulation technique for the analysis of can making process using PAM-STAMP software. The processes consist of doming and necking in addition to drawing, redrawing. After body making process, this study analyzed the stability for internal pressure by simulating buckling test. Through these technique, we estimated the dome reversal pressure of steel D&I Can for various can profile and process conditions. From this study, we found the cause and mechanism of wrinkling during necking process. This mechanism is largely affected by can wall thickness and the clearance between knock out punch and necking die. The dome reversal pressure improves with increasing dome depth. These results validate the usefulness of the developed simulation technique for the analysis of body making process and optimization of the dome profile.

• Design & Manufacturing
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• v.9 no.1
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• pp.18-22
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• 2015

Mold making and product manufacturing process was made by a die through a number of stages. Thereby, it takes a long period of time from the manufacture of mold until passed the products to consumers. However, it is not possible to meet the diverse desires purchasing of consumer. We made a 3D CAD Model aligned with product scan data using reverse engineering. Utilizing thereafter flow analysis to derive the optimal mold conditions, by applying the condition, and devised a mold fabrication process that is much shorter than the conventional process for fabricating a mold. In this study, the outlet cover to the product, it describes a process, as a result, it was confirmed that the number of steps can be shortened much more than the conventional process.

• Design & Manufacturing
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• v.6 no.1
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• pp.73-78
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• 2012

The aim of this dissertation is inferring factors controlling the complex strain behavior of the material and the characteristics of the Fine-Blanking in the most narrow area at the shear zone where we are performing the Fine-Blanking. And also this is for inspecting and presenting their uses and the possibilities to make the results data based in order to utilize easily. Therefore, to analyze of shere zone's strain behaviour, the Fine-Blanking process need to be modelled defining the quadratic-nodded and axi-symmetrical elements as the problems of large deformation axi-symmetry and the non-linear contact. For the method of inputting strain-stress values of the material, the piece-wise linear technics were used, the Implicit-Finite Element method also used making balance of forces on each step by the long intervals, calculates and converges many times was done. The materials used for the analysis was the Steel SNCM220 5.5mm respectively. As the result of FEM analysis, we know that shear stress value in the beginning of punch penetration is distributed widely and done high both in the center of the late-thickness and on the both sides centering around shear strain zone as the punch penetration is increasing. Also.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.64-76
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• 1997

This paper deals with development of brackets by using aluminum alloy sheets which is indispensable for weight reduction of autobody. The press formability of aluminum alloy sheet is estimated by means of tensile test, V bending test, sample manufacturing test and photograph of microstructure. The results show that the elongation, strength, work hardening exponent, plastic anisotropy coefficient of Al 6***series are better than those of Al 5***series, but for general press formability, Al 5***series are better than Al 6***series due to lower yield strength. Since most of mechanical properties of aluminum sheet are generally inferior to those of cold-rolled steel sheet, shape fixability and press formability of aluminum sheet are very poor. For making components of autobody by use of die for steel sheet application, it is essential that die should be nodified for least bending and stretching. With the modified die for aluminum, it could be possible to make brackets, the component of autobody. Microstructure of Al 5***series has fine grain and small the 2nd phase and that of Al 6***series has relatively coarse grain. Therefore, it seems that fine grain and small the 2nd phase of Al 5***series is one of the factor of lower yield strength, resistance to stamping work, formation of Luder's line.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.179-185
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• 2012

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize casting design of an automobile part (Gear Box) Computer Aided Engineering (CAE) was performed by using the simulation software (Z Cast). The simulation results were analyzed and compared with experimental results. During the mold filling, internal porosities caused by air entrap were predicted and reduced remarkably by the modification of the gate system and the configuration of overflow. With the solidification analysis, internal porosities caused by the solidification shrinkage were predicted and reduced by the modification of the gate system. For making a better production die casting tool, cooling systems on several thick areas are proposed in order to reduce internal porosities caused by the solidification shrinkage.

• Design & Manufacturing
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• v.9 no.1
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• pp.14-17
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• 2015

In the data from synthetic resin makers, there is no shrinkage deviation through injection molding. But, after making the required products, even in the same conditions, there are some size-deviation in colors. Into our research, we checked main factor by the injection molding conditions. Our tests have shown this results, there are some shrinkage deviation in collors and, in the injection molding conditions, packing pressure is the main factor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.569-574
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• 2002

As consumer's desire becomes various, agility of mold manufacturing is most important factor for competence of manufacturer. In common works to use commercial CAM system to generate tool path, some decision making process is required to produce optimal result of CAM systems, The paper proposes a methodology for computer-assisted tool selection procedures for various cutting type, such as rough, semi-rough and finish cuts. The system provides assist-tool-items for machining of design model part of injection meld die by analyzing sliced CAD model of die cavity and core. Also, the generating NC-code of the tool size is used to calculate machining time. The system is developed with commercial CAM using API. This module will be used for optimization of tool selection and planning process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.250-255
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• 1992

This paper discusses how to develop a standard time for face cutting. The discussion focusses especially on the useful experert and law data for automated generate standard time purposes. Make standard time is a means to realize the process planning. Also process planning is a process which expresses design. In past times, a process planning was done using only experience of expert. But nowadays many people try to make automated process planning. This paper discusses standard time of the face cutting, but except making process sequence. In order to make standard time, some rules have to be generated and some industrial data found out. So we can calulate standard time in die. This is to easer and to correct calulate standard time. Using some rules that are application oriented to every parts of die.