• 열처리공학회지
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• 제33권3호
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• pp.99-106
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• 2020

Selective laser melting (SLM) is an additive manufacturing process by melting metallic powders and stacking into layers, and can product complex shapes or near-net-shape (NNS) that are difficult to product by conventional processes. Also, SLM process is able to raise the efficiency of production by creating a streamlined manufacturing process. For manufacturing in SLM process using Ti-6Al-4V powder, analysis of microstructural evolution and evaluation of mechanical properties are essential because of rapid melting and solidification process of powders according to high laser power and rapid scan speed. In addition, it requires a post-processing because the soundness and mechanical properties are degraded by defects such as pore, un-melted powder, lack-of-fusion, etc. In this study, hot isostatic press (HIP) was conducted as a post-processing on SLM-printed Ti-6Al-4V alloy. Microstructure of post-processed Ti-6Al-4V alloy was compared to as-built Ti-6Al-4V, and the evolution of quasi-static (Vickers hardness, room temperature tensile characteristic) and dynamic (high-cycle fatigue characteristic) mechanical properties were analyzed.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.95-107
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• 1999

The design models of a new product in general are created using clay models or wooden mock-ups. The reverse engineering(RE) technology enables us to quickly create the CAD model of the new product by capturing the surface of the model using laser digitizers or coordinate measuring machines. Rapid prototyping (RP) is another technology that can reduce the product development time by fabricating the physical prototype of a part using a layered manufacturing technique. In reverse engineering process, however, the digitizer generates an enormous amount of point data, and it is time consuming and also inefficient to create surfaces out of these data. In addition, the surfacing operation takes a great deal of time and skill and becomes a bottleneck. In rapid prototyping, a faceted model called STL file has been the industry standard for providing the CAD input to RP machines. It approximates the CAD model of a part using many planar triangular patches and has drawbacks. A novel procedure that overcomes these problems and integrates RE with RP is proposed. Algorithms that drastically reduce the point clouds data have been developed. These methods will facilitate the use of reverse engineered geometric data for rapid prototyping, and thereby will contribute in reducing the product development time.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.158-163
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• 2001

This study is the selection of optimum forming condition for RP system using ADS. Program using ADS reduces the required time for feedback between design and manufacturing of workpiece. When we produce rapid prototype using RP system, we investigate the relationship between Facetres in system variable number of AutoCAD and roundness of rapid prototype, and we will find optimum forming condition in RP system.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.30-35
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• 2002

Nowadays, as the development period of new products becomes shorter and consumer's requirement is more various, the importance of Rapid Prototyping Technology has been rapidly increased. Rapid Prototyping makes prototypes or frictional parts directly using the 3D CAD data. But RP machines can make prototypes in limit size. For making large size prototype, we slice solid which is made of STL file, and then glue sliced solid. And if contact area of part is small, union solid will be easily destroyed for going down of adhesion. So we need to expand contact area, 1 suggest making a section into stair shape. This paper is concerned with slicing solid on STL file and improving on adhesion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.903-906
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• 1995

In this paper,human body models have been manufactured by the use of rapid prototyping techniques, which are to be used for surgery planning in clinical practice. In this manufactacturing process, CT or MRI data of human bodies are prepared and the images are processed to obtain sectional contours. With these contours, three-dimensional surface triangulated models are constructed, which finally transformed to STL file for rapid prototyping. For this purpose, total service system for manufacturing of human body models is constructed by employing commercial softwares, and the related problems and process parameters are investigated

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.204-209
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• 1995

The implementation of rapid prototyping technologies has been developed for automotive engineering by utilizing concurrent engineering principes integrated with slective laser sintering. The Selective Laser Sintering, in which a part is generated in layers form powder using a computer-controlled laser scanning apparatus and power feed system. An over view of the basic principles of SLS Machine operation is given. Binding mechanisms are described for power which becomes thermally activated bye the scanning laser beam; viscous flow and melting of a low-melting-point phase in powder. The production of parts from metal is described, including post processing to improve structural integrity and induce a transformation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.483-486
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• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing processes a new product. The functional requirements of a rapid prototyping system are high speed and high accuracy, and they depend on the operating parameters, some of which can be set by users. The accuracy is evaluated by dimensional errors and form errors of manufactured pars. A specially designed specimen with various features has been used for the accuracy evaluation. According to the Taguchi experimental design techniques, and orthogonal array of experiments has been set which has the least number of experimental runs to find the parametric effects. A laser scanner is used to obtain the point data of the parts and Surfacer is used to determine the lengths and angles. The conditions for the FDM manufacturing parametrs have been found.

• 한국공간구조학회논문집
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• 제15권3호
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• pp.61-68
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• 2015

A study on BRP(Building Rapid Printing) technology is in an initial stage although general 3d printers are being developed in a great speed and with fruitful outputs. Even some laboratories in advanced countries have difficulties in their research due to many technological restrictions and have not produced a practical output yet. This paper proposed distinct directions in which the research of this aera should be developed and this manifested four areas - printing speed, reinforcing tech, material tech and nozzle tech and those areas were proposed with concrete development alternatives and objects.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.105-108
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• 1997

To reduce design period, demands for rapid prototyping system is increasing. Among the rapid prototyping system, as a concept modeler, 3D Printer appears before the footlights. In spite of short production time and convenience, 3D Printer causes post processing problem. And that is too slow to adapt to the demand of workshop. In this research, we developed a system for reducing build time and roughness using splitting operation. Also, propose BFS(B-rep For STL) data structure to maintain model data, split STL model and implement Euler Operation for input and output.

• Journal of Welding and Joining
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• 제22권2호
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• pp.46-50
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• 2004

In today's highly competitive marketplace, it is of great significance for the manufacturing industry to reduce lead-time and costs fur the product development. Since first emerged in 1986, Rapid Prototyping (RP) technology has helped successfully to reduce time and costs. Recently, RP using functional materials such as metal has been researched. However RP using the molten metal has been struggling to resolve several drawbacks, such as dimensional inaccuracy, poor surface finish, post finishing, etc., that originate primarily from the overall deposition of molten metal for each layer. So, the purpose of this study is to develop a new RP technique using sheet metal and projection welding for reducing several drawbacks in occurring RP using molten metal. Also tensile and bending specimens were made by the developed RP process using projection welding and were verified.