• 대한기계학회논문집A
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• 제20권5호
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• pp.1582-1589
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• 1996

Rapid prototyping is a new prototyping technology which produces three dimensional part models directrly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Appaaratus(SLA) which is the most widely-used rapid prototyping system is introduced to achieve die/mold technology innovation. For the purpose, the prototyping technology using SLA is developed such that patterns of which shapes are quite complicated are successfully produced with high accuracy. Using these patterns, prototype die/molds are efficientrly manufactured; a turbocharger rotor, a fan and a wheel patterns, prototype die/molds are efficienterly manufactured ; a turbochager rotor, a fan and a wheel pattern are made, and the molds of the investment casting, the injection molding and the die casting are manufactured respectively. The casting products are produced using these molds and it turns out that these methods are quitre effective for manufacturing products of complicated geometry from the viewpoint of efficiency and productivity.

• 대한치과기공학회지
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• 제22권1호
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• pp.49-55
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• 2000

In manufacturing the all-ceramic crown whick look close to natural teeth, the effectiveness of the improved technique is expectected the technique of the heat treatment of gold plating coating die was experimented of a refractory cast model. The following results were obtainde 1. An advantage of build up on east die with out manufacturing veneer, crown, core, or masking(reduction of technical process, and retrenchment of time and money) 2. Esthetically more close to natural teeth than other technique 3. Easy to remove a refractors cast die 4. In manufacturing ceramo-metal crown the enomous effectiveness was obtainde on applying in the areas of cervical margin, the metal surface, and in the treatment of pinhole.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.263-266
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• 2008

We apply a closed die forging technology to a large crankshaft of which forging weight amounts to 850kg. 40ton counter-blow hammer forging machine is used. The forging process is optimized to reduce the forming load using finite element simulation. AFDEX 3D is used for forging simulation. The experiment is compared with finite element prediction and a good agreement is observed. The successful development of a large crankshaft by the closed die forging technology will contribute to opening a new area of closed-die forging application and to enhancing competitiveness of national machinery industries especially including ship part and power generation industries.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.1-7
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• 2023

Recently, in the semiconductor industry, memory device market is focusing on producing ultra-thin wafers for high integration. In the wafer manufacturing process, wafers after backgrinding and CMP process must be picked up as individual dies and subjected to be peeled off from the dicing tape. However, ultra-thin dies are vulnerable to the possibility of breakage and failure in their thickness and size. This research studies the mechanism of peeling a die with a high-aspect ratio using a thermopneumatic method instead of a die ejector with physical pins. Setting compressed air and the temperature as main factors, we determine the success of the digester using thermopneumatic system and analyze the good die to find the possibility of making mass-production equipment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.316-321
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• 2000

Die Casting is one of the forming methods to manufacture large number of products with short period time and clean surface by high forming pressure and temperature of cast alloy. Die design is composed of selection of cast alloy, design of die casting product, runner and gate design etc. In reality, however, die design of die casting has been performed by trial and error method, which cause economic and time loss. This paper describes a research work of developing computer-aided design of die casting product and die design. Approach to the CAD system has been written in AutoLISP on the AutoCAD with personal computer. In this study, die design system for gate of die casting process has been developed to present algorithm for automation of die design, especially runner-gate system. As forming process and die design system using 3-D geometry handling are integrated with technology of process planning, die design is possible to set. In addition, specific rules and equations for the runner-gate system have been presented to avoid too many trails and errors with expensive equipment. It is possible for engineers to make automatic and efficient die design of die casting and it will result in reduction of expense and time to be required. An example is applied to cap-shaped casting using proposed algorithm.

• 한국기계가공학회지
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• 제15권2호
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• pp.22-30
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• 2016

It is very important to obtain the net shape of the product to maximize the shear cutting surface of fine blanking. In this paper, the fine blanking die was manufactured to achieve part characteristics, such as flatness and a fully sheared surface. The V-ring in the fine blanking die was designed to prevent lateral movement of the material. The fine blanking experiment was conducted with the fine blanking die. The material usage rate was increased by over 5.7% and that of the water-soluble lubricant was decreased by over 33% when the 2-cavity die technology was applied to fine blanking. The capacity of the existing press could lead to productivity improvement and cost reduction. Thus, 2-cavity die technology for fine blanking with a minute module of an accurate gear for producing seat recliner parts was developed.

• 소성∙가공
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• 제14권5호
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• pp.444-451
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• 2005

A new extrusion process of the circular section product with helical fins could be developed by rotating extrusion die. The twisting of extruded product is caused by the twisted conical die surface connecting the die entrance section and the die exit section linearly. But, until now, because the process has used fixed extrusion die, it needs high pressure in order to twist billet and form fin shape on the surface of billet. So, during extruding billet, in order not to twist billet, the extrusion die is needed to rotate itself instead of twisting of billet. It is known that it is possible to reduce extrusion load of product with helical fins by analysis and experiments using rotating die. And it is known that, through the extrusion load analysis by $DEFORM^{TM}-3D$ software, optimal rotational velocity of rotating die can be obtained according to reduction ratio of area and twisted angle of die. And experiments and analysis using rotating extrusion die show that the twisted angle of product can be controlled by twisted angle of extrusion helical die and the rotational velocity of extrusion helical die.

• 소성∙가공
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• 제10권4호
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• pp.302-310
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• 2001

The twisting and extrusion process of the product with involute helical fin from the round billet is developed by the upper bound analysis. The twisting of extruded product is caused by the twisted inclined die surface connecting the die enterance section and the die exit section linearly. In the analysis, the internal shear surface is defined as the curved twisted plane from the twisting of die surface and the shear work is calculated by the consumption of shear energy. The increase rate of angular velocity is determined by the minimization of plastic work. The angular velocity of die exit can be controlled by the land length and the length of inclined die. The alular velocity assums to be increased linearly by the axial distance from the die enterance to the die exit. The results of the analysis show that the angular velocity of the extruded product increases with the die twisting angle, the reduction of area, and decreases with the die length, the friction constant.

• 소성∙가공
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• 제16권6호
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• pp.479-487
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• 2007

Die life is generally estimated taking failure life and wear amount into consideration. In this study, the forging die life was investigated considering both of these two factors. The fatigue life prediction for the die was performed using the stress-life method, i.e. Goodman's and Gerber's equations. The Archard's wear model was used in the wear life simulation. These die life prediction techniques were applied to the die used in the forging process of the socket ball joint of a transportation system. A rigid-plastic finite element analysis for the die forging process of the socket ball was carried out and also the elastic stress analysis for the die set was performed in order to get basic data for the die fatigue life prediction. The wear volume of the die was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.249-254
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• 2000

The contact forces between die components for the drawing of large size automotive panels introduce elastic deflections of the die components. Due to the deflections, the gap between blank holder and die varies locally resulting in nonuniform material flow. Such a nonuniform die gap usually requires correcting operation, so called die spotting, which is time consuming trial and error process. To reduce the die spotting time, the optimization of the blank holder bending deflection is needed. In this paper, we implemented an analysis procedure to predict the blank holder deflection. The analysis procedure and design of experiments techniques are applied to the optimization of balance block heights. The optimization results can be used as guidelines in actual die spotting process.