• Transactions of Materials Processing
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• v.12 no.2
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• pp.102-109
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• 2003

In the manufacturing process of metal matrix composites parts, thixoforging is one of the most effective forming processes. The major purpose of the current study is to provide the proper conditions such as the die shape, the forging velocity, the forging time, the forging pressure and reinforcement injection velocity and pressure on various defects in thixoforged cylinder liner, filling tests were performed by MAGMA S/W. In order to evaluate the effectiveness of the calculated conditions which is given by computer aided engineering, A357, A380 and SiC$_{p}$/A380 cylind~5$mu extrm{m}$r liner were fabricated under the calculated conditions. SiC$_{p}$/A380 composite billets were fabricated by both the mechanical stirring and electrical magnetic stirring process. Incase fo SiC$_{p}$/A380 composite cylinder liner, reinforcement distribution and effect of reinforcement(SiC$_{p}$) content(10~20 vol. %)and size(5.5~14${\mu}{\textrm}{m}$) on the mechanical properties were investigatedstigated.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.3-10
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• 2007

A new approach based on implicit surface interpolation combined with domain decomposition is proposed for filling complex-shaped holes in a large polygon model, A surface was constructed by creating a smooth implicit surface from an incomplete polygon model through which the actual surface would pass. The implicit surface was defined by a radial basis function, which is a continuous scalar-value function over the domain $R^{3}$. The generated surface consisted of the set of all points at which this scalar function is zero. It was created by placing zero-valued constraints at the vertices of the polygon model. The well-known domain decomposition method was used to treat the large polygon model. The global domain of interest was divided into smaller domains in which the problem could be solved locally. The LU decomposition method was used to solve the set of small local problems; the local solutions were then combined using weighting coefficients to obtain a global solution. The validity of this new approach was demonstrated by using it to fill various holes in large and complex polygon models with arbitrary topologies.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2402-2406
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• 2005

A collision query determines the intersection between given objects, and is used in computer-aided design and manufacturing, animation and simulation systems, and physically-based modeling. Bounding volume hierarchies are one of the simplest and most widely used data structures for performing collision detection on complex models. In this paper, we present hierarchy of oriented rounded bounding volume for fast proximity queries. Designing hierarchies of new bounding volumes, we use to combine multiple bounding volume types in a single hierarchy. The new bounding volume corresponds to geometric shape composed of a core primitive shape grown outward by some offset such as the Minkowski sum of rectangular box and a sphere shape. In the experiment of parallel close proximity, a number of benchmarks to measure the performance of the new bounding box and compare to that of other bounding volumes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.24-29
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• 2002

In any rapid prototyping process, the layer by layer building process introduces an area error between the staircase and the surface line specified by the computer-aided design model. This affects the dimensional accuracy as well as the surface finish for different part build orientations. This paper describes a methodology for computing the area error for any orientation of the part built by the fused deposition modelling system. This technique can be applied to determine the best build orientation of the part, based on the minimum area error. This technique is verified by comparing the results with the experimental measurements of the area error of the parts built at different orientations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.229-234
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• 1999

This thesis presents the design method using CAE(Computer Aided Engineering) with the consideration of reliability for optimal gear driving system. The validity and feasibility of the proposed method are verified by the application to transmission of machine tool. The reliability and life analysis is based on the two-parameter Weibull distribution lives of the gears and bearings. Ninety-percent of reliability life is the life of the component or system in million output rotations or hours at which ninety percent of identical components or system would survive under the given loading conditions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.1
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• pp.24-31
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• 2005

The outsole mold of the shoes has been manufactured using electro-discharge machining by graphite electrode or using casting etc. The study is concerned with the pattern design for the outsole of shoes by CAD, the modeling and the generation of NC data by CAM system and the machining by CNC machining center. The ball end mill and the engraving cutter is used as cutter and the cutting conditions are adjusted according to the shapes and sizes of the cutter and part in cutting. The method showed the possibility coping with the rapid change of shoes industry and proposed the possibility for higher productivity and quality on mold-manufacturing of shoes outsole.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.14-19
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• 2015

Since CAD is advertised 1980s, all across industries have been changed through engineering, manufacturing and inspection. Also marine industry has adopted not only CAD but also various IT systems to make productivity higher. This paper includes research and development to improve traditional draft reading by using IT system, it has focused to build draft database for new vessels, to improve robustness measuring weather condition and to reduce accident possibility.

• Design & Manufacturing
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• v.15 no.2
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• pp.36-41
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• 2021

The 3 dimensional Pipe (Annular) Shaped Products was selected as a test sample, then a attribute of a molding shrinkage according to the parameters of a injection process was examined with PC, which is the typical engineering plastic. Both the inside and the outside diameter of the Pipe (Annular) sample were shrank into the inner direction of the part. And then the comparative analysis of the samples proved that a increasing thickness led a bigger shrinkage rate in the equal outside diametric samples, and a decreasing outside diameter caused a bigger shrinkage rate in the same thickness samples. The comparative study of the cushion volume of a injection machine showed that the molding shrinkage was most affected by the pressure strength among the resin temperature, the maintenance pressure strength and the maintenance pressure duration time. Each of the shrinkage rates according to the measuring direction and the gate position was different. As a result, the injection molded sample had not a typical circular shape.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.173-178
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• 2018

The direct metal laser sintering (DMLS) technique would be promising for the full-arch implant-supported restorations due to reduced cost and manufacturing time without potential human errors and casting defects. The aims of this case report were to describe the successful outcome of an implant-supported fixed dental prosthesis in the edentulous maxilla by using the DMLS technology and computer-aided design and computer-aided manufacturing (CAD/CAM) monolithic zirconia crowns, and to describe its clinical implications. A healthy 51-year-old Korean woman visited Seoul National University Dental Hospital and she was in need of a rehabilitation of her entire maxilla due to severe tooth mobility. In this case, all maxillary teeth were extracted and an implant-supported fixed dental prosthesis was fabricated that involved a cobalt-chromium (Co-Cr) framework with the DMLS technique and CAD/CAM monolithic zirconia crowns. Six months after delivery, no distinct mechanical and biological complications were detected and the prosthesis exhibited satisfactory esthetics and function. In this case report, with the DMLS system, the three-dimensional printed prosthesis was created without additional manual tooling and thus, reliable accuracy and passive fit were obtained.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.126-132
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• 2005

In this paper, an auto-design system is introduced for a stamping tool based on commercial computer aided design system with its drafting language. The auto-design system consists of tool oriented product design subsystem which modifies and configures the product drawing, tool concept design subsystem which make a design of the punches and their punching progression and parts design subsystem that makes automatic dimension. The system is applied to the mechanical design of the stamping tool. The main logic of the system is based on half-edge theory, a kernel for the 3 dimensional CAD system, which is applied to 2 dimensional drafting auto-design system. The auto-design system enables to conspicuously reducing the designing time of the tool. In addition, there is little drafting error that had been about 3% without auto design program. It is effective to reduce the development time for new products because of rapid designing time of the tools, standardization of the stamping tool and the drafting rule for the auto-design system. The auto-design system yields high efficiency of the tool manufacturing system.