• 한국정밀공학회지
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• 제18권1호
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• pp.117-122
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• 2001

Many kinds of channels are used in industrial equipment and production machinery. Although mechanical saw has been used to cut many sorts of channels, there is cost rise problem because of low productivity. Shearing of channel has a special place because it helps to cut expected shape and size easily. A channel cutting die set which can be mounted and used on a hydraulic press is developed to improve the productivity of channel cutting process. Mode for the channel cutting is divided into single cut and double cut method. This study use double cut method, and the developed channel cutting die set is composed of upper and lower die set. Shearing time can be reduced from 40 minutes to 20 seconds using the developed channel cutting die set. The productivity of channel cutting process can be increased with shearing time reduction as well as cost reduction.

• 소성∙가공
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• 제32권2호
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• pp.61-66
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• 2023

The quality of the sheared surface affects the stretch flangeability of steel sheet. The quality of sheared surface is influenced by several process factors such as die clearance, shape of cutting edge, use of counter punch, and shear. In this paper, the influence of these shearing process factors on the stretch flangeability of the HSS (DP980) was analyzed through a shearing and a stretch flangeability test. When the die clearance was 10%, the effect of these shearing process factors on the stretch flangeability was the greatest, and the use of an acute angle blade was found to be more advantageous in the stretch flangeability than a right angle blade. It was found that the stretch flangeability was improved when active bending was applied during shearing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.79-80
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• 2006

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.269-270
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.819-820
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• 2010

• 암석학회지
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• 제18권4호
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• pp.293-305
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• 2009

경상분지 영양지괴와 의성지괴가 접하는 길안-청송 지역은 선캠브리아기 변성암류, 트라이아스기 청송 화강암, 백악기 퇴적암류(일직층, 후평동층, 점곡층), 그리고 백악기 화성암류(안산암, 석영반암, 규장암) 등으로 구성되어 있으며, (서)북서, 북북서, 동북동, 남북, (북)북동 등 경상분지를 대표하는 다양한 방향의 단층들이 발달한다. 본 연구는 이들 단층의 발달사 및 운동성을 조사하기 위해 길안-청송 지역에 발달하는 단열계의 기하학적 운동학적 특성을 파악하였다. 그 결과, 연구지역내 발달하는 단층들의 운동성은 대부분 주향이 동성으로 인지되며, 방향성별 단열조의 출현빈도는 동북동, 북북서, (서)북서, (북)북동, 남북 등의 방향 순으로 높게 나타난다. 방향성별 단열조의 연장성은 (서)북서, 북북서, 동북동, (북)북동, 남북 등의 방향 순으로 우세하게 나타나고, 이러한 우세 방향성은 단층들의 연장성과 거의 일치한다. 방향성별 단열조의 발달사 및 운동성은 (1) (서)북서 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (2) (서)북서 방향과 북북서 방향 단열조의 공액성 전단단열운동(전자: 우수향, 후자: 좌수향) $\rightarrow$ (3) 북북서 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (4) (서) 북서 방향 단열조의 좌수향 전단단열운동 $\rightarrow$ (5) 동북동 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (6) 동북동 방향과 남북 방향 단열조의 공액성 전단단열운동(전자: 좌수향, 후자: 우수향) $\rightarrow$ (7) (북)북동 방향 단열조의 좌수향 전단단열운동 등으로 요약되고, 이러한 연구결과는 길안-청송 지역에 발달하는 단층들의 발달사 및 운동성과 밀접한 관련성 있다.

• 소성∙가공
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• 제14권1호
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• pp.37-42
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• 2005

In order to invstigate the influence of die design variables on the quality of the sheared surface in cutting of sandwich sheet metals, the cut-off operation is carried out, which is the typical shearing process in sheet metal forming technology. For experiments we made the cut-off die which can be easily adjusted for die design variables such as blankholding force, pad force and clearance. The sandwich sheet metals considered are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results it is shown that the shearing mechanisms are different according the material of which sandwitch sheet metal is composed. The influence of die design variable is explored and we found optimal conditions for both sandwich sheet metals. It is expected that this investigation can be utilized to get the better sheared surface.

• 한국광학회지
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• 제13권2호
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• pp.98-104
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• 2002

비구면 광학부품의 수차 측정 및 성능 평가를 위해 특별 설계된 층밀리기 간섭계를 소개하고, 이와 더불어 층밀리기 간섭계가 갖는 자체의 계통오차를 측정결과로부터 제거하기 위한 보정 방법을 제안한다. 층밀리기 간섭계의 계통오차는 크게 간섭광학계가 갖는 광학오차와 간섭계의 기구부의 불완전에 기인한 층밀리기 방향의 직교오차로 구분할 수 있다. 이들 두 계통 오차들은 모두 본 논문에서 제안하는 방법으로 모두 보정될 수 있다. 보정 방법은 측정 대상물을 간섭계의 광축을 중심으로 회전하여 측정결과로부터 계통오차를 분리하는 자가보정 원리에 근거한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.349-352
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• 2006

The plastic deformation of polycrystalline materials is induced by changes of the microstructure when the loading is beyond the critical state of stress. Constitutive models for the crystal plasticity have the common objective which relates microscopic single crystals in the crystallographic texture to the macroscopic continuum point. In this paper, a new consistent tangent stiffness for the anisotropic elasto-viscoplastic analysis of polycrystalline deformation is developed, which can be used in the finite element analysis for the slip-dominated large deformation of polycrystalline materials. In order to calculate the consistent tangent stiffness, the state function is defined based on the consistency condition between the elastic and plastic stress. The rate of shearing increment($\Delta{\gamma}^{\alpha}$) is calculated with satisfying the consistency condition. The consistency condition becomes zero when the trial resolved shear stress($\tau^{{\alpha}^*}$) becomes resolved shear stress($\tau^{\alpha}$) at every step. Iterative method is utilized to calculate the rate of shearing increment based on the implicit backward Euler method. The consistent tangent stiffness can be formulated by differentiating the rate of shearing increment with total strain increment after the instant rate of shearing increment converges. The proposed tangent stiffness is applied to the ABAQUS/Standard by implementing in the ABAQUS/UMAT.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.805-810
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• 1997

In this paper the technique to predict tool were theoretically in the sheet metal shearing process is suggested. The were in sheet metal tool affects the tolerances of final parts, metal flows and costs of processes. In order to predict the tool were the deformation of workpiece during the process is analyzed by using non-isothermal finite element program. The ductile fracture criterion and the element kill method are also used to estimate if and where a fracture will occur and to investigate the features of the sheared surface in shearing process. Results obtained form finite element simulation such as node velocities and node forces are transformed into sliding velocity and normal pressure on tool monitoring points respectively. The monitoring points are automatically generated and the were rates on these points are accumulated during a process. It is assumed that the wear depth on the tool surface are linear function of the lot sizes based upon the known experimental results. The influence of clearance between die and punch upon tool wear is were is also discussed during the process.