• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.318-321
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• 2007

This paper is concerned with improvement of surface quality of a sheet metal member in the stamping process. The CAE procedure of the stamping process is utilized in order to investigate cause of surface troubles and to improve surface quality. A complicated shape of the sheet metal member can induce surface troubles such as wrinkles because of insufficient tensions force and non-uniform contact of a blank sheet with tools. This paper proposes two guidelines such as a change of tool shape and added draw-beads on the tool surface in order to increase tension forces and to induce uniform contact. The proposed guidelines are verified with the CAE of the stamping process. The CAE results show that the changed shape of tools and added draw-beads can reduce the amount of wrinkles and improve surface quality.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.86-93
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• 2010

The tilting index table has attached to CNC machining center with 3axes, it can be improvement of its performance and its machining efficiency. The tilting index table is a key unit in order to manufacture some non-rotational and 3-dimensional parts, using the conventional machining center. In this study, structural analysis is carried out by FEM simulation using the commercial software ANSYS Workbench 11 to develop tilting index table using direct drive motor. The shape of the tilting index table obtained from the optimization was analyzed and compared with the initial model. Also, the initial model was modified based on the optimization model and the result was verified to have the acceptable improvement.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.45-51
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• 2021

The purpose of this study is to suggest the optimal shape for a local air ventilation system for fume removal, which is operated in a zinc galvanizing factory, and to propose the improvement plan for a ventilation system used in a zinc galvanizing factory through flow analysis. A part of the air sprayed by an air curtain goes out. It will be necessary to research the position of an air curtain, its spray angles, and its nozzle shape. In addition, additional research needs to be conducted on the shape of the fan installed before a hood in order to make it easy to induce fume. In a local air ventilation system, air is inhaled from the outside. The higher an inlet negative pressure is, the easier fume is removed. It was found that it was necessary to install an appropriate hole in the wall on the back of a push nozzle in order to reduce an inlet negative pressure.

• Transactions of Materials Processing
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• v.30 no.2
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• pp.69-73
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• 2021

This paper addresses the product shape modification for spring-back reduction in the sheet metal forming process of the cabin sunroof which is applied to the construction equipment. Initially, the anisotropic material properties are measured in order to calculate the degree of spring-back by the numerical simulation of the sheet metal forming process. To reduce the spring-back of the stamped part, several design modifications are suggested according to the geometrical bead arrangement on the planar region. The degrees of spring-back are confirmed for various product designs with different use of the geometrical bead. Finally, the spring-back improvement was validated by manufacturing the tryout product with the modified die set for the optimized product shape.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.19-26
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• 2014

The cross flow turbine attracts more and more attention for its relatively wide operating range and simple structure. In this study, a novel type of micro cross flow turbine is developed for application to a step in an irrigational channel. The head of the turbine is only H=4.3m and the turbine inlet channel is open ducted type, which has barely been studied. The efficiency of the turbine with inlet open duct channel is relatively low. Therefore, a guide nozzle on the turbine inlet is attached to improve the performance of the turbine. The guide nozzle shapes are investigated to find the best shape for the turbine. The guide nozzle plays an important role on directing flow at the runner entry, and it also decreases the negative torque loss by reducing the pressure difference in Region 1. There is 12.5% of efficiency improvement by attaching a well shaped guide nozzle on the turbine inlet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.85-88
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• 2001

Deep drawing process, one of sheet metal forming methods, is used widely. Circular or square shape blanks are currently studied mainly. Especially, circular blank for coating case of chip condenser remains bridges when it is made out of aluminum coil. The bridge reduces Material-withdrawal-rate of aluminum coil to $60\%$. This paper proposes a no-bridge blank instead of circular blank. To get the different values of two cases, comparison circular blank with no-bridge blank is accomplished in the point of thickness strain in the vicinity of flange. In order to find optimal condition in new proposed blank, several process variables - those are blank holder shape, die shape radii, punch shape radii and blank holding force - are changed.

• The Journal of Advanced Prosthodontics
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• v.2 no.3
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• pp.77-80
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• 2010

This article describes esthetic improvement in a patient with a missing maxillary left central incisor. Space analysis of the anterior dentition showed that minor tooth rearrangement was needed. Optimal space distribution for restorations was attained by orthodontic treatment. Through transforming tooth shape with porcelain laminate veneers, the maxillary left lateral incisor was transformed into central incisor and the maxillary left canine into a lateral incisor. The maxillary right central incisor was also restored for esthetic improvement. In a case of changing a tooth shape with porcelain laminate veneers, pre-treatment evaluation, space analysis and diagnostic wax-up are important factors.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.188.2-188.2
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.221-222
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.261-262
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• 2007