• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.69-77
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• 2020

This paper proposes an effective method of giving users feedback on 3-dimensional drawing and measures its performance to ensure that feedback can help users enter the correct position in 3D. In the experiment of drawing a given line shape using a hand-held controller, the user is provided with three levels of visual, auditory, and haptic feedback for the position input error. As a result of analyzing the position input accuracy according to the type of feedback, all types of feedback are able to significantly reduce errors, and visual feedback and haptic feedback are more effective than auditory feedback.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.66-74
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• 2019

In the field of shipbuilding design, the use of 3D CAD is becoming commonplace, and most of the large shipyards are conducting 3D design. However at the production site, workers are still working on 2D drawings rather than 3D models. This tendency is even worse in small-scale shipyards and block manufacturing shops. Particularly, in a manufacturing shop that is engaged in the outsourcing of blocks, it may not be possible to provide 3D model. However, the demand for 3D models in the production field is steadily increasing. Therefore, it would be helpful if 3D model could be generated from a 2D drawing. In this paper, we propose a method to extract template and unfolded surface shape information from shell template offset drawing using computer vision technology. Also a 3D surface model was reconstructed and visualized from the extracted information. The result of this study is thought to be helpful in the work environment where 3D model information can not be obtained.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.141-145
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• 2000

A systematic method to find the optimal blank shape for sheet forming is proposed by coupling the numerical simulation technique. A weighted parameter was introduced in order to simplify the multi-variable optimization problem to a single-variable problem. The proposed method has been applied to the blank design of drawing processes to obtain the near-net shape within the required error bound after forming, Excellent results have been obtained between the numerical results and the target contour shapes. Through the investigation the proposed systematic method for optimal blank design is found to be effective in the practical forming processes

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.7
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• pp.1141-1148
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• 1997

In the stamping industry the blank shape to be stamped into a designed shape has been conventionally determined from the try out process by the press engineers. The work needs a lot of time and thus leads a loss of productivity. In this study boundary element method for 2-dimensional potential problem was used to design optimum blank shapes for irregular press forming. Here we assumed that the blank is controlled by blank holder only and material flow at blank holder was under potential flow. The developed PC code for designing the optimum blank shape shows that the blank shapes for optimal drawing can be calculated within a few minute in pentium PC and the calculated shapes agree well with the experiments. However the application of this method is constrained only to the pressed product with flat bottom.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.46-49
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• 2009

An optimal design procedure is proposed to effectively reduce the torque ripple by optimizing the rotor pole shape of the spoke type IPMSM with concentrated winding. The procedure is composed of two steps. In step I, the steepest descent method (SDM) is used with only two design variables to rapidly approach the optimal shape. From the near optimal rotor shape as a result of the step I, the design variables are reselected and the drawing spline curves are utilized to explain more complex shape with the Kriging model in step II. By using an optimal design procedure, we show that the optimized rotor pole shape of the spoke type IPMSM effectively reduces the torque ripple while still maintaining the average torque.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.927-928
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.426-429
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• 2005

In this study, the formed tool is used to machine of bearing raceway and a shape compensation scheme is proposed to compensate for shape of it in turning process. It is introduced the conventional design method of the formed tool; a simple depth compensation method and a drawing compensation method. And it is performed to investigate in detail properties of the formed tool about a tool angle and problems of a turning process of bearing raceway using the formed tool. The applicability of the proposed scheme is examined by comparing the experimental results obtained by a new designed formed tool with those obtained by a conventional tool.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.185-195
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• 1998

A new blank design method is proposed to predict the optimum initial blank shape in the sheet metal forming process. The rollback method for blank shape design takes the difference between final deformed shape and target contour shape into account. Based on the method, a computer program composed of blank design module, FE-analysis program and mesh generation module is developed. The rollback method is applied to square cup drawing process with the flange of unifiorm size around its periphery to confirm its validity. The optimum initial blank shape is obtained from an arbitrary square blank after three modifications. Good agreements are recognized between the numerical results and the published results for initial blank shape and thickness strain distribution. The optimum blank shape for two parts of automobile sub-frame is designed. The thickness distribution and the level of punch load is improved. Also, the method is applied to design the weld line in the tailor-welded blank. It is concluded that the rollback method is an effective and convenient method for an optimum blank shape design.

• Journal of Korean Elementary Science Education
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• v.27 no.1
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• pp.31-41
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• 2008

The purpose of this research is to investigate the preconceptions of the Earth for 3rd grade students in elementary school. For this study, We interviewed with 30 students and children responded the questions with drawing the pictures. Through the study, We could find as followings. First, they thought that the shape of Earth is sphere only except one who had double conceptions of sphere and flat. Second, the color of the earth seems to be blue because of sea, but mostly answered, it seems to be green more than brown because of continent. Third, the conceptions of the gravity showed us 43% which is the kinds of scientific conceptions for the Earth.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.2
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• pp.38-47
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• 2001

This paper decribes the development of computer-aided design of a very precise progressice die for lead frame of semiconductor chip. The approach to the system is based on knowledgr-based rules. Knowledge of fie이 experts. This system has been written in AutoLISP using AutoCAD ona personal computer and the I-DEAS drafting programming Language on the I-DEAS mater series drafting with on HP9000/715(64) workstation. Data exchange between AutoCAD and I-DEAS master series drafting is accomplished using DXF(drawing exchange format) and IGES(initial graphics exchange specification) files. This system is composed of six main modules, which are input and shape treatment, production feasibility check, strip layout, data conversion, die layout, and post processing modules. Based on Knowledge-based rules, the system considers several factors, such as V-notches, dimple, pad chamfer, spank, cavity punch, camber, coined area, cross bow, material and thickness of product, complexities of blank geometry and punch profiles, specifications of available presses, and the availability of standard parts. As forming processes and the die design system using 2D geometry recognition are integrated with the technology of process planning, die design, and CAE analysis, the standardization of die part for lead frames requiting a high precision process is possible. The die layout drawing generated by the die layout module s displayed in graphic form. The developed system makes it possible to design and manufacture lead frame of a semiconductor more efficiently.