• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.2
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• pp.88-93
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• 1981

The three force components of shear spinning are calculated by a newly proposed deformation model. The spinning process is understooed as shearing deformation arter uniaxial yuelding by ending, and shear stress .tau.$\sub$rz/ becomes .kappa. the yueld limit in pure shear, in the deformation zone. The tangential forces are calculated and then the feed forces and normal foeces are obtained by assuming a nuiform distribution of roller pressure on the contact surface. An optimum contact area is obtaned by minimizing the bending energy required to obtain the assumed deformation mechanism. The calculated forces are compared with experimental data form published literature and present experiments. Good agreement cetween calculated and experimental values for working forces is obtained over a wide range of process variables.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.633-638
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• 2012

The doctor blade is a core part of a laser printer and directly influences the printing quality. The main specifications for doctor blades ate for them to be precise and durable. It is necessary to study an automatic production system for doctor blades in order to obtain high-efficient manufacturing processes. In this paper, the technology and the design of the automatic production line has for manufacturing doctor blades has been researched. The automated manufacturing process consists of five steps, which are the supplying of raw material, shearing, bending, bracket supplying, and the laser-spot welding process. The proposed automatic manufacturing system allowed for faster and more reliable production of doctor blades.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.466-469
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• 2002

Burr is a projected part of finished workpiece. It is unavoidable and undesirable by-product of most metal cutting or shearing process. Also, it must be removed to improve the fit of machined parts, safety of workers, and the effectiveness of finishing operation. But deburring process is one of manufacturing processes that have net been successfully automated, so deburring automation is strongly needed. This paper focused on developing a basic algorithm to find edge of workpiece and match two different image data for deburring automation which includes automatic recognition of parts, generation of deburring tool paths and edge/corner finding ability by analyzing the DXF drawing file which contains information of part geometry. As an algorithm for corner finding, SUSAN method was chosen. It makes good performance in finding edge and corner in suitable time. And this paper suggested a simple algorithm to find matching point between CCD image and drawing file.

• Geomechanics and Engineering
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• v.8 no.1
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• pp.33-52
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• 2015

Based on the Mohr-Coulomb failure criterion, a gradient-dependent plastic model that considers the strain-softening behavior is presented in this study. Both triaxial shear tests on conventional specimen and precut-specimen, which were obtained from an ancient landslide, are performed to plot the post-peak stress-strain entire-process curves. According to the test results of the soil strength, which reduces from peak to residual strength, the Mohr-Coulomb criterion that considers strain-softening under gradient plastic theory is deduced, where strength reduction depends on the hardening parameter and the Laplacian thereof. The validity of the model is evaluated by the simulation of the results of triaxial shear test, and the computed and measured curves are consistent and independent of the adopted mesh. Finally, a progressive failure of the ancient landslide, which was triggered by slide of the toe, is simulated using this model, and the effects of the strain-softening process on the landslide stability are discussed.

• Fashion & Textile Research Journal
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• v.3 no.1
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• pp.20-24
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• 2001

The primary objective of this study was to empirically explore the mechanical properties of marketing Korean fabrics by using KES-FB system and estimate the sewability of Korean clothes by the mechanical properties. From the empirical research, it was found that Korean fabrics for spring and summer has been transformed easier and less flexible by shearing Korean fabrics for autumn and winter. Also, it was found that there is a significant difference in the hand value as tensile, surface and compression. It was found that Korean fabrics for spring and summer has a stiffness and elastic properties of matter and Korean fabrics for autumn and winter has a bulky and abundant elasticity. Finally, it was found that Korean fabrics for autumn and summer in the joint of account of the mechanical properties. Also, the difficulties of process has been expected by sewability like seam-pucker, over feed, sewing and steam-press.

• Transactions of Materials Processing
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• v.19 no.5
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• pp.290-295
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• 2010

Shaving technology is one of the significant metal forming technologies which can make the smooth and fine sheared surface of products after shearing process. The sheared surface on the side wall of the cutting edge is very important because it functions as a basic surface for measuring the dimensions of product. Effective sheared surface after shaving can be influenced by several working variables such as shaving allowance, shaving clearance, type of material and profile of cutting edge. The influence of these variables on shaving characteristics was investigated in this study. A cut-off die to make the simplified gear-shaped products was manufactured. Three kinds of sheet metals (AL5052, SPCC and SAPH440) of 3mm thickness were firstly sheared and then shaved for four shaving allowances and three sharing clearances. It was shown through experiments that the optimum working condition to give the maximum effective sheared surface in shaving was found ; Shaving allowance is 0.2mm and Shaving clearance is 0.01mm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1358-1371
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• 1988

The combustion process is the most important process in the S.I. engine since it determines performance and emissions. As the flame propagates slowly due to EGR or lean mixture, the fast burn system is widely used in the modern engines in order to improve engine performance. As the basic research for the fast burn system of the S.I engine, this study is aimed to identify the effects of the intake port design on the air motion inside a cylinder. In this study various intake ports were designed and tested. Swirl levels for the different intake ports were measured by a swirl meter and LDv.Also transient air motion inside a cylinder is further investigated following the motion of the boston. Out of the various intake ports tested in this study the masked shroud head (MSH) generates the highest swirl while keeping satisfactory volumetric efficiency. The MSH port also produces high level of turbulence by shearing action between cylinder wall and swirl.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.806-818
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• 2006

The shear spinning process, where the plastic deformation zone is localized in a very small portion of the workpiece, shows a promise for increasingly broader application to the production of axially symmetric parts. In this paper, the three components of working force are calculated by the newly proposed deformation model in which the spinning process is understood as shearing deformation after uniaxial yielding by bending, and shear stress, $\tau_{rz}$ becomes $\kappa$, yield limit in pure shear, in the deformation zone. The tangential forces are first calculated and the feed forces and the normal forces are obtained by the assumption of uniform distribution of roller pressure on the contact surface. The optimum contact area is obtained by minimizing the bending energy required to get the assumed deformation of the blank. The calculated forces are compared with experimental results. A comparison shows that theoretical prediction is reasonably in good agreement with experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.16-23
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• 2021

The fracture characteristic of the bonded interface under the application of a sliding load to a double cantilevered specimen manufactured using lightweight material was examined. Inhomogeneously bonded materials such as Al6061-T6, CFRP, and CFRP-Al were employed. In the experiment, the specimen was loaded on both directions by applying a shearing load to the bonding interface. The experimentally obtained stress, specific strength and energy release rate values were examined. CFRP exhibited excellent specific strength. The experimental results demonstrated that the inhomogeneous bonded material CFRP-Al exhibited an overall high performance in comparison with the single materials.

• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.968-975
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• 2005

The shearing process for the sheet metal is normally used in the precision elements such as semi-conductor components. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional de-burring process, so this imposes high cost on manufacturing. In this paper, we have developed the in-situ auto-aligning precision meso-punching system to investigate the burr formation mechanism and ultimately minimize burr. Firstly, we introduced the punch-die contact sensing method to align the punch and the die at initial state prior to the punching process. Secondly, by using the low-price semi-con­ductor laser, burr formed on the edges is measured intermittently during the punching process. We could, finally, make burr on the sheet metal uniformized and minimized by controlling of the precision X - Y table, $1\;{\mu}m$ resolution, and measuring burr height by semiconductor laser. Experimental results show the validity of our system for pursuing the burr-free punched elements.