• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.52-56
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• 2006

Punching tools like an electrodes are made by milling or etching or EDM. These methods had time consuming, low efficiency and air pollution. So, we have developed a shearing device which counter punching method for burrless cutting of micro wire. Using the straightened SUS304 wire with $200{\mu}m$ diameter, we confirmed the tendency of the shear plane for punch tools. It was impossible to completely remove the bun in the shearing process. In order to minimize the burr size and fine shear plane, we have accomplished the various experiment conditions such as the U-groove, the effect of the counter punch, shear angle and clearance. The results of the experiments show that indentation, slip plane and bent shape were related to the shear angle and clearance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.448-452
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• 2005

Punching/blanking/shearing is among the oldest and most frequently used sheet metal forming process. We have developed the shear device for burrless cutting using the micro wire. Since the burr minimization and fine shear plane, this paper is a study on the effect of the shear angle and clearance of the cutter-cutter. And, we confirm the tendency of the shear plane. It is impossible to completely remove the burr in the shearing process. In order to minimize the burr size and fine shear plane, we have accomplished the various experiment conditions such as the shear angle and clearance. Despite the quality of shear plane is not good enough yet, it is possible to make the burr minimization and fine shear plane by the optimization of process parameters.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.121-126
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• 2005

Micro wires manufactured by the straightening process are used in the BT(Bio-Technology), IT(Information-Technology), NT(Nano-Technology). We have developed a novel wire straightener which uses the direct heating method(DHM) for straightening the micro wire and shearing device for burr-less cutting. In this study, we confirm the tendency of micro wire after the shearing process. It is impossible to remove the burr in the shearing process. However, the embodiment of minimum burr size after the shearing process is the best in-process method. In order to minimize the burr size, we have accomplished the various experiment condition such as the U-groove, the effect of the counter punch, the shear angle, clearance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1440-1443
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• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1647-1650
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• 2008

The moyamoya disease is a type of cerebrovascular disease which produces thin abnormal blood vessels like haze in the brain base because the end of internal carotid artery which supplies about 80% of blood is blocked. Regarding this moyamoya disease, the shearing stress and thrombus generation are mentioned as its main causes. This study three-dimensionally implemented the ICA, ACA, and MCA parts of the cerebrovascular configuration related to the moyamoya disease, and analyzed the hydrodynamic phenomenon with the commercial program ADINA. In particular, the correlations between shearing stress and speed distribution according to the branch angle of ACA and MCA. A numerical analysis found that the greater the branch angle of ACA and MCA, the lower the shearing stress and the greater the stationary area of the flow.. Put Abstract text here.

• Design & Manufacturing
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• v.10 no.3
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• pp.34-38
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• 2016

Roll forming is a continuous production process that is mass-produced. The roll forming process is produced in various forms. The special feature of roll forming is a continuous production. Therefore, the process of cutting the material is essential. The troubles in a shearing process affects the low productivity. Accordingly, it is important to reduce the factors that inhibit the material flow. And it is difficult to apply the common shear angle. Because it is not a simple forms, such as a progressive die. This study shows how to select the angle of a shear punch and the shape of a cutting punch in the product with a specific shape. Conclusively through three different model, it is advantageous to apply the different shear angle and clearance along the forms.

• Transactions of Materials Processing
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• v.23 no.8
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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.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.105-112
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• 2009

In this study, a series of direct shear tests were performed to investigate the characteristics of friction angles for sands and interface friction angle between sands and construction materials with respect to different relative density of the Nak-dong River sands and shearing velocity. The result of the test shows that friction angles of sands are always higher than interface friction angle between sands and construction materials. As the shearing velocity get faster, the friction angles of sand became higher. With respect to the density of sand by reducing void ratio, friction angles increase linearly, and relevant equations were proposed to calculate the friction angle by changing void ratio and relative density of sand. The interface roughness of construction materials was also an important factor in interface friction angle.

• Journal of the Korean Geotechnical Society
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• v.38 no.2
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• pp.29-38
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• 2022

The friction anisotropy of shear resistance can be selectively used in geo-structures. For example, larger axially loaded deep foundation, soil nails, and tiebacks increase load carrying capacity due to induced large shear resistance while pile penetration and soil sampling produce minimal shear resistance. Previous studies confirmed direction-dependent shear resistance induced by interface between soil and surface asperity of plate inspired by geometrical shape of snake scale. The aim of this paper is to quantitatively evaluate interface friction angle with different surface asperities. Using the modified direct shear test, a total of 51 cases, which sand are prepared at the relative density of 40%, are conduced including 9 plates, two shear direction (shearing direction against the height of surface asperity is increased or decreased during shearing test), and three initial vertical stress (100 kPa, 200 kPa, 300 kPa). Experimental results show that shear stress is increased with higher height of surface asperity, shorter length of surface asperity, and the shearing direction that the height of surface asperity increases. Also, interface friction angle is decreased with larger surface asperity ratio, and shearing direction with increasing height of surface asperity produces larger interface friction angle regardless of the surface asperity ratio.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1225-1226
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• 2013