• Design & Manufacturing
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• 제12권2호
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• pp.11-15
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• 2018

In this study, we proposed three analysis methods to calculate the flatness of torque-angle sensors (TAS). We introduced two statistical and one geometrical methods in evaluating the precision of the flat plane in the axis direction for TAS. To verified the results, we fabricated TAS and a reference sample using a injection molding machine, mold, polyester as a raw material. We measured ($x_i$, $y_i$) position using 3D contact automated system and applied three analysis methods developed for TAS and a reference sample to see the feasibility. While each analysis method has its own pros and cons, the analysis using the shortest optimal distance was the most precise technique for the flatness evaluation of TAS components.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.153-158
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• 2006

Nowadays, hollow upper-shaft of monobloc type has been considered for weight reduction and high quality in the automobile industry. To form the upper-shaft under tube cold extrusion, Taguchi method is applied to optimize the die design in this study. Taguchi method for optimum die design is to establish the optimal combination of design parameters and to reduce a number of experiments. Effect of parameters including the die relief, mandrel, die half angle is investigated and analyzed based on FEA analysis using a FEM commercial software MSC_Marc. Furthermore extrusion experiments have been performed to verify the results investigated in the FEM simulations.

• Journal of Advanced Marine Engineering and Technology
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• 제29권3호
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• pp.275-280
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• 2005

Recently there has been a growing interest in the design and manufacturing of the muffler tube due to the strict environment regulations, A muffler is an important part used to reduce noise and to purify exhaust gas in cars and heavy equipment. The shape of the muffler tube and the number of the tube hole has been made variously according to the weight and function of the car. The perforating technique of the muffler tube has a great influence on the manufacturing cost. In this study, metal forming analysis has been carried out to investigate the perforating process for the muffler tube and predict an optimal forming conditions of the muffler tube, Also its simulation results by the finite element method were reflected to the die design and the manufacturing system for the muffler tube. The perforating process is performed in the longitudinal direction of the tube. According to the simulation results, when the shear angle of punch was similar to the tube curvature, the optimal shape was obtained. Also when the clearance of die was 0.2mm, the burr was minimized and optimal shear section was obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.575-578
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• 2000

Die design to minimize the die wear in the cold forging process is very important as it reduce the production cost and the increase of the production rate. The quantitative estimation for the die wear is too hard because the prediction of the die wear is determined with many process variables. So, in this paper, the optimal shape of the backward extrusion punch is newly designed through the FE-analysis considering the surface expansion and Archard's wear model in order to reduce the rapid wear rate that is generated for the backward extrusion product exceeding the forming limit. The main shape variables of the backward extrusion punch are the flat, angle, and round of the punch nose part. As the flat and angle of the punch nose are larger, the surface expansion is reduced. and, the wear rate is decreased according to the reduction of the punch round. These results obtained through this study are applied to the real manufacturing process, it is implemented the reduction of the wear rate.

• 한국정밀공학회지
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• 제21권10호
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• pp.180-187
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• 2004

Die design to minimize the die wear in the cold forging process is very important as it reduce the production cost and the increase of the production rate. The quantitative estimation fur the die wear is too hard because the die wear is caused by many process variables. So, in this paper, the optimal shape of the backward extrusion punch is newly designed through the FE-analysis considering the surface expansion and Archard wear model in order to reduce the rapid wear rate that is generated for the backward extruded products exceeding the forming limit. The main shape variables of the backward extrusion punch are the flat diameter, angle, and round of the punch nose part. As the flat diameter and angle of the punch nose are larger, the surface expansion is reduced and the wear rate is decreased according to the reduction of the punch round. These results obtained through this study can be applied to the real manufacturing process.

• 소성∙가공
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• 제27권3호
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• pp.165-170
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• 2018

In order to increase the lifetimes of cold forging dies, insert rings are generally used. In this study, an insert ring and shrunk ring of the flange upsetting die were designed for the cold forging of an automotive wheel nut. The Stress distribution occurring in the die during forging was simulated using a commercial finite element analyzing program. The effects of the fitting interference and inclined angle of the insert ring on the compressive stress of the die inside were also investigated. The simulated data were compared with the real lifetimes of the forging dies. The maximum compressive stress acting on the edge of a forging die should have the most influence on die lifetime, an idea which could help develop the die design with the longest lifetime. The design of the most optimal forging die with the longest lifetime is made possible by analyzing the maximum inner pressure and principal stress between the shrunk ring and insert ring.

• 소성∙가공
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• 제8권6호
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• pp.569-575
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• 1999

Computer programs have been developed to design the forging dies of turbine and compressor blades. The design of forging dies is based the side force and the filling of die cavity. In this study, slab method has been applied to simulate forging processes numerically. the program composed of Visual Basic also provides the informations of mean stress, total forging load, distribution of temperature, position of neutral line, total volume and volume of flash in the final stage to users. The preform position is predicted by the reverse slab method. The program has been successfully applied to various types of turbine blades.

• 대한기계학회논문집A
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• 제37권7호
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• pp.865-873
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• 2013

CNG 압력용기의 제조를 위하여 고성능 수평식 프레스를 이용한 딥드로잉과 아이어닝의 연속공정(D.D.I. 공정)이 도입되었다. 그러나, 몇몇 D.D.I. 공정 변수들은 현장 경험에 의존하여 결정되는 문제점이 있으며, 다이의 짧은 수명 역시 고성능, 저비용의 압력용기 제조를 위하여 필수적으로 개선되어야 한다. 본 연구에서는, 공정의 신뢰성 확보 및 다이 수명 향상을 위하여 기존 관련 연구 및 현장 경험을 바탕으로 드로잉비, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도를 공정변수로 결정하였다. FEA 를 이용하여 각 성형 단계에서 찢어짐과 주름이 발생하지 않는 한계 드로잉비를 결정하였고, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도에 대하여 실험계획법을 이용하여 최적 공정설계를 수행하였으며, 기존 공정에 의한 결과와 비교하여 효율성을 검증하였다.

• 한국주조공학회지
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• 제20권2호
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• pp.97-103
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• 2000

In this study, a design of experiment, Taguchi method, was applied to optimize gating system design of escalator step die casting parts. Six shape factors which affect filling sequence of melt are adopted and divided into two levels respectively. Initial feeding differences of melt which were calculated by using S/N(signal-to-noise) ratio in each condition were demonstrated with the simulation of Flow-3D software program. Variations of S/N ratio according to shape factors were obtained and the optimal condition of gating system could also be obtained. It could be found that width of gate, contact angle of gate, thickness of runner are more effective factors on the filling sequence of melt than the others in this case of escalator step die casting parts. It showed that the economical gating system and sound filling sequence of melt were obtained by using Taguchi method.

• 소성∙가공
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• 제23권8호
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• pp.501-506
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• 2014

Progressive shearing with blanking dies is commonly employed to produce large quantities of tiny sheet metal electronic parts. Sheet metal pins, which are narrow and long, that are sheared with a progressive die set are often twisted. The twist in the sheet metal pins, which usually occurs in the final shearing operation, generally decreases with increasing blank holding force. The blank holding forces in all shearing operations are not the same because of different shearing positions and areas. In the current study, the optimal layout of the springs in a progressive die set to minimize the twist of the sheet metal pin is proposed. In order to find the holding force acting on the tiny narrow blanks produced with the proposed springs during the shearing process, the equivalent area method is used in the structural analysis. The shearing of the sheet-metal pin was simulated to compute the twist angle associated with the blank holding force. The constraint condition satisfying the pre-set blank holding force from the previous shearing operations was imposed. A design of experiments (DOE) was numerically implemented by analyzing the progressive die structure and by simulating the shearing process. From the meta-model created from the experimental results and by using a quadratic response surface method (PQRSM), the optimal layout of the springs was determined. The twist of sheet metal pin associated with the optimal layout of the springs found in the current study was compared with that of an existing progressive die to obtain a minimal amount of twist.