• 대한기계학회논문집A
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• 제34권11호
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• pp.1623-1630
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• 2010

본 연구에서는 자동차용 시트 리클라이너의 주요 부품인 섹터투스 결합부의 롤오버 저감을 위한 효과적인 성형 방법을 제시하였다. 기존의 성형 공정에 의하여 발생한 과도한 롤오버 때문에 섹터투스 내측기어와 결합 부품인 폴투스 외측기어 간의 정확한 결합이 이루어지지 않아 승차감 및 안전성이 저하된다. 따라서 성형 시, 소재를 롤오버 측으로 유동시켜 롤오버량을 최소화 해야 하며, 이를 위하여 국부 돌기형 다이, 코이닝 펀치를 이용한 방법 및 가변 역클리어런스를 통한 롤오버 저감 방법에 대해 유한요소해석으로 비교 평가 하였고, 이를 검증하기 위해 금형 제작 및 실험을 수행하였다. 실험 결과, 가변 역클리어런스를 이용한 방법이 롤오버 저감 및 금형 강도 측면에서 우수한 특성을 가지는 것을 확인할 수 있었다.

• Design & Manufacturing
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• 제9권1호
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• pp.5-8
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• 2015

The company Daewoo Precision Industries imported fine blanking press of 40 tons from Switzerland with fine blanking tool in order to produce the fuse part of bomb in 1978 at first in Korea. About 1985 the first fine blanking tool for producing the door lock parts was manufactured in the company Gold Star (now LG). And then this technology was grown up with the growth of automobile industries in Korea. Now 31 companies are closely related to the fine blanking technology and there are total 146 fine blanking presses in Korea. The developments of fine blanking technology in industries have been oriented to the production of precise fine blanking parts, the reduction of die roll height on fine blanking parts, the production of complex fine blanking parts with progressive fine blanking tool including forming and forging technology, the production of high-strength steel fine blanking parts and so on. Some R&D activities in KITECH were introduced.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 2부
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• pp.824-827
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• 2011

본 논문에서는 자동차 시트 리클라이너 기어의 파인 블랭킹 성형 실험을 통하여 V-링 설치 위치에 따른 기어의 다이 롤 높이 변화를 검토하였다. 3 종류의 다이 편과 가이드 플레이트 편을 설계하여 파인 블랭킹 금형을 제작하였으며 650 ton 파인블랭킹 프레스에서 성형 실험을 수행하였다. 실험으로부터 제품을 취출하여 다이 롤 높이를 측정하여 분석한 결과 기어 모듈과 관계없이 V-링 설치 위치가 가이드 플레이트에서 멀어짐에 따라 다이 롤 높이가 증가함을 파악할 수 있었다. 이와 같은 결과는 향후 파인 블랭킹 금형의 V-링을 설계할 때 다이 롤 높이를 최소화하기 위하여 유용하게 활용될 수 있을 것이다.

• 소성∙가공
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• 제25권4호
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• 한국기계가공학회지
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• 제12권6호
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• pp.84-92
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• 2013

This study improves the formability in fine-blanking the lock plate of car seat belts using a low carbon steel(SM35C) plate. The optimal die design for the forming process is proposed using rules for process planning based on theories and field experiences. The optimal design is analyzed using commercial finite element software in order to solve the fracture problems in the extrusion process. Through the improved layout based on the FEM results, the fracture of the extruded part and the roll over problem are solved. Furthermore, it is demonstrated through the shown from experiments that the extruded part does not break in the modified die.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1476-1479
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• 1996

발전설비나 자동차 그리고 항공우주분야에 사용되는 각종 bearing, 원형부품들에 사용되는 ring을 생산하는 방법중, 가장 효과적이고 경제적인 방법은 ring rolling (ring 압연)이다. 이 방법은 직경 50cm에서 2m이상의 원형 ring을 연속적으로 짧은 시간내에 (한 ring당 약 1분) 생산 가능하다. 이제까지의 수학적 모델을 사용한 제어시스템은 ring의 단면적이 사각형인 제품에는 최소한의 오차로 생산 가능하였으나, plant의 생산성과 제품의 다양성을 위하여 ring의 단면적이 복잡한 것을 생산시에는 문제점이 노출되었다. 왜냐하면 기존의 수학적모델이 roll gap 또는 metal forming zone에 근거하여 modelling하였기 때문이다. 본 논문에서는, 이러한 문제점을 고전적인 수학적 모델을 기초로한 adaptive control system의 방법대신에, 축적된 control system설계와 운용 경험을 이용하여 설계한 퍼지제어기 및 그것의 실적용 그리고 그 결과를 소개한다. 실적용 결과는, 제조된 단면적이 상대적으로 복잡한 bearing의 형상이 (filling grad)이 제어기의 제어정도 판단기준이었는데, 99.5%의 형상도를 보임으로서 industry에서 요구하는 제품기준을 만족시켰다. 또한 짧은 제어기 설계 및 on-line optimization 기간 또한 이 제어기의 장점이었다.

• 한국기계가공학회지
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• 제11권6호
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• pp.152-157
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• 2012

This study investigates compressive strength of ice pellet strip which is potential medium for Natural Gas Hydrate(NGH) extruded from die holes of Twin-roll Press for Continuous Pelletizing(TPCP). Recently, the prototype of TPCP is newly developed where ice powder is continuously fed and extruded into strip-type pellet between twin rolls. The system is specifically designed for future expansion towards mass-production of ice pellet strips or solid form of natural gas hydrate. It is shown that the compressive strength of pellet strip heavily depends on factors in extrusion process such as disk size, surface smoothness, ring size, taper shape, feeding mechanism, and rotational speed. Here, the mechanism of TPCP, along with compressive strength of pellets is discussed in terms of its feasibility for producing NGH pellets in the future.

• 소성∙가공
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• 제18권1호
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• pp.67-72
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• 2009

This paper covers finite element simulations to evaluate tube bending process of auto chassis component i.e. trailing-arm product. The rear of the auto chassis structure is primarily composed of CTBA and trailing-arm. When a car rolls into a corner, the trailing arm reacts to roll in the same degree as the car body. During the bending process of trailing arm the tube undergoes significant deformation. Thus forming defects such as excessive thinning and flattening of the tube will be formed in the outside of the tube. In this paper, we analyzed the effect of process parameters in rotary draw bending process and searched the optimized combination of process parameters using orthogonal arrays method to minimize the forming defects. In this process we analyzed several parameters which are displacement of pressure die, boosting force, initial position of mandrel bar, dimensions of mandrel in regarding to the thinning and flattening of the tube.

• 소성∙가공
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• 제25권2호
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• pp.116-123
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• 2016

Press-brake bending is used to shape flat and thick plates into a targeted circular configuration without excessive localized thinning or thickening. A brake bending press called 'a knife press bending apparatus' has been widely adopted to manufacture thick, large and long pipe from initially thick plate. Submerged Arc Welded (SAW) pipes are also produced by employing press-brake bending. These pipes are mainly used for oil, natural gas and water pipelines. The principal process variables for press-brake bending can be summarized as stroke of the press-brake knife, the distance between both roll in the lower die, and the feeding length of the plate. Many combinations of these process variables are available, thus various pipe diameters can be realized. In the current study, a series of repetitive numerical simulations by feeding a thick plate with initial thickness of 25.4mm were conducted with the consideration of elastic recovery. Furthermore, an index for SAW pipe production is proposed which can be widely used in industry.