• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.417-422
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• 2000

In the process of die manufacturing, according to increasing demand of die and molds, the efficient machining of dies and molds has been increased. However, while the cutting process has been automated by the progress of CNC(computer numerical control) and CAD/CAM, the polishing process still depends on the experienced knowledge of an expert. Also, even when workers are skilled in polishing dies. it takes much time to obtain the required roughness and smoothness on the surface of a die. Moreover, many workers gradually avoid doing polishing work because of the poor working conditions caused by dust and noise. Therefore, to improve productivity and to solve the potential shortage of skilled workers, a user-friendly automatic polishing system was developed in this research. The developed polishing system with five degrees of freedom is able to keep the polishing tool normal to the die surface during operation and is able to maintain a pressure constantly by the developed pneumatic system. Also, to evaluate polishing performance of the developend system and find the polishing conditions, the various polishing experiments were carried out.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1415-1418
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• 2008

Scaffold fabrication for regenerating functional human tissues has an important role in tissue engineering, and there has been much progress in research on scaffold fabrication. However, current methods are limited by the mechanical properties of existing biodegradable materials and the irregular structures that they produce. Recently, Solid freeform fabrication (SFF) technology was remarked by fabricating 3D free-form micro-structures. Among SFF technologies, we tried to fabricate scaffolds using micro-stereolithography which contain the highest resolution of all SFF technologies and precision deposition system which can use various biomaterials. And we developed the CAD/CAM system to automate the process of scaffold fabrication and fabricate the patient customized scaffolds. These results showed the unlimited possibilities of our SFF technologies in tissue engineering.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.683-688
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• 1994

Recently, the Z-Map model has been used widely to represent the three dimensional geometric shape and to achieve the cross-section and point evaluation of the shape. In this paper, the CNC cutting planning and simulation modules for product with three dimensional geometric shape are realized based on the Z-Map model. The realized system has the various capabilities related to the automatic generation of tool path for the rough and finish cutting processes, the automatic elimination of overcut, the automatic generation of CNC program for a machining center and the cutting simulation. Especially, the overcut-free tool path is obtained by using the CL Z-Map models which are composed of the offset surfaces of the geometric shape of product.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.160-168
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• 1999

This paper describes one method of reverse engineering that machines a free form shape without descriptive model. A portable five-axes 3D CMM was used to digitize point data from physical model. After approximation by rational B-spline curve from digitized point data of a geometric shape, a surface was constructed by the skinning method of the cross-sectional design technique. Since a surface patch was segmented by fifteen part, surface merging was also implemented to assure the surface boundary continuity. Finally, composite surface was transferred to commercial CAD/CAM system through IFES translation in order to machine the modeled geometric shape.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.929-932
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• 2002

As 3-D solid modeling systems have been widely used in product design recently, dedicated design systems for molds of the products have been developed and introduced to mold manufacturers. These mold design systems provide solid modeling capabilites for mechanism to free undercuts. This paper describes an algorithm for slide design capability that has been developed based on a commercial CAD system, Unigraphics. Since the relationship between slide parts were investigated and predefined using parameters in the system, the dimensions and locations of the parts are modifed automatically when a part is modified.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.442-451
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• 2015

Smartphone users are 15 billion in all round the world, and Korean smartphone users are estimated at 40million people to 83% of the Korean population. Selfie stick is most popular item among 20, 30's age users. And they use smartphones more than 90%. In survey they express inconvenience of using selfie stick. Inconveniences are as follows. * Heavy * Handle is inconvenient. * Mistiming during taking pictures * the range of shooting is not enough. In this paper the first improvement was that rod strength is slightly stronger. The second we divide a grip into 3 parts. If 3 parts are unfolded, these can use for tripod. We use deflection Interpretation for main Finite Elements Method program.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.491-495
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• 2015

Currently, selfie stick, a monopod take selfie photographs, got its popularity. Cradle used to connect selfie stick and smartphone usually uses electric force of spring to get smartphone fixed. But, using electric forces makes it hard to attach and detach smartphone from the cradle and gives possibility of smartphone falling down. CoQue suggests new solution of smartphone cradle by using cable tie (patent number US 8407863 B2) instead of electric force. It will give more easy and stable way of using selfie stick.

• CDE review
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• v.21 no.2
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• pp.27-30
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• 2015

Smartphone users are 15 billion in all round the world, and Korean smartphone users are estimated at 40million people to 83% of the Korean population. Selfie stick is most popular item among 20, 30's age users. And they use smartphones more than 90%. In survey they express inconvenience of using selfie stick. Inconveniences are as follows. * Heavy * Handle is inconvenient. * Mistiming during taking pictures * the range of shooting is not enough. In this paper the first improvement was that rod strength is slightly stronger. The second we divide a grip into 3 parts. If 3 parts are unfolded, these can use for tripod. We use deflection Interpretation for main Finite Elements Method program.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.470-477
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• 2017

Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.429-436
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• 2003

A new linkage framework between elastic shell element with finite rotation and computar-aided geometric design (CAGD) (or surface is developed in the present study. The framework of shell finite element is based on the generalized curved two-parametric coordinate system. To represent free-form surface, cubic B-spline tensor-product functions are used. Thus the present finite element can be directly linked into the geometric modeling produced by surface generation tool in CAD software. The efficiency and accuracy of the Previously developed linear elements hold for the nonlinear element with finite rotations. To handle the finite rotation behavior of shells, exponential mapping in the SO(3) group is employed to allow the large incremental step size. The integrated frameworks of shell geometric design and nonlinear computational analysis can serve as an efficient tool in shape and topological design of surfaces with large deformations.