• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.189-195
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• 2000

RP techniques have their unique characteristics according to the working principles : star-stepped surface of parts due to layer-by-layer stacking low build speed caused by line-by-line solidification to fish one layer and post processing to improve surface finish etc The objective of this study is to propose a new RP technique Variable Deposition Mnanufacturing (VDM) which can make up for the disadvantages of the existing RP techniques and to develop an apparatus to implement the technique. The proposed process can greatly reduce the build time and improve the surface finish of parts generated. Experiments are carried out to obtain the range of temperature of molten material to maintain its fluidity and to investigate the effect of gas cooling on the preservation of the slopes. Some simple shapes such as a line-shape an S-shape and a circle-shape are fabricated from Ethylene Vinyl Acetatecopolymer(EVA) In order to examine the applicability of VDM to more general shapes a tensile specimen and a yo-yo shape were manufactured by the proposed RP method using EVA material as a trial approach. The current basic study shows a high potential of practical use of the proposed VDM process to prototyping of a general three-dimensional shape.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1067-1070
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• 2002

Fused deposition modelling(FDM) is a rapid prototyping(RP) process that fabricates part layer by layer by deposition of molten thermoplastic material extrude from a nozzle. RP system has many benefit. One of the benefit would be the ability to experiment with physical objects of any complexity in a relatively short period of time. But it has a matter of surface roughness and geometric accuracy. We study on Influence of tangent line angle on surface roughness at fused deposition

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.1
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• pp.45-50
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• 2003

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 Road Widths. This paper describes a methodology for computing the area error for any Road Width by the fused deposition modelling system. This technique can be applied to determine the best Road Width 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 with Road Widths.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.3-6
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• 2001

The present work concerns rapid tooling technology based on three-dimensional CAD/CAM. Two types of tooling processes have been introduced : the quick delivery molding(QDM) process and the rapid tooling(RT) process using a rapid prototyping system. Both processes are based on three-dimensional CAD/CAM technology and realize a paperless manufacturing system with a high efficiency. The proposed approach has been applied to the product development for various electrical parts, and the final delivery has been reduced as compared with the traditional approach.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.7-16
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.104-110
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• 2001

The rapid prototyping and tooling technology has been developed. However, most commercial ones currently use resins or waxes as the raw materials. These days, the direct metal deposition methods are being investigated as new rapid prototyping and tooling technology. A fundamental study on rapid prototyping and tooling with wire welding technology using CO2 laser radiation was carried out in this paper. The main focus is to develop a simple commercial rapid prototyping and tooling system with the exiting laser welding technology as output and their microstructure, hardness and tensile strength are examined for the reliability. In addition, its advantages and disadvantages are discussed as a rapid prototyping and tooling system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.327-330
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• 2004

Laser aided direct metal deposition (LADMD) process offers the ability to make a metal component directly from 3-D CAD dimensions. A 3-D object can be formed by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using optical sensors is introduced to control laser power and powder mass flow rate. Using H13 tool steel and $CO_2$ laser system, comprehensive analysis are executed to test the efficiency of the system. In addition, the dimensional characteristics of directed deposited material are investigated with the parameters of deposition thickness, laser power, traverse speed and powder mass flow rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.83-86
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• 1997

Even as many methods and technologies have been introduced on data generation, parts orientation and layer slicing to acquire the rapid prototyping(RP) parts that have useful surface to satisfy customers' needs such as stylingldesign verification directionlindirect tooling directly from the RP machine, these trials continue to suffer from the surface roughness due to the build characteristics of RP technology. A new postprocess finishing method is suggested in this paper to overcome the surface roughness problem on the surface of the RP parts. To prevent deterioration of dimensional accuracy from the conventional grinding-only, and coating-grinding methods, 4-step surface finishing process is applied. To satisfy the various requirements from the RP oriented industrial f elds, effective procedure, coating material, grmd~ng tools and methods are employed.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.174-178
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• 2001

In order to reduce the lead-time and cost, recently the technology of rapid protoyping and manufacturing(RPM)has been widely used. Machining process is still considered as one of the effective RPM methods that have been developed and currently available in the industry. It also offers practical advantages such as precision and versatility. Some considerations are still required during the machining process. One of the most important points is fixturing. There should be an effective method of fixturing since the fixturing time depends on the complexity of geometry of the part to be machined. In this paper, the rapid manufacturing process has been developed combining machining with automatic filling. The proposed fixturing technique using automatic filling can be widely applicable to free surface type of product such as a fan. In the filling stage, remeltable material is chosen for the filling process. An automatic set-up device attachable to the table of the machine has also been developed. The device ensures the quality during a series of machining operations. This proposed process has shown to be a useful method to manufacture the required products with the reduced the response-time and cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.110-114
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• 2002

The master pattern manufacturing process is one of the most important processes in jewelry industry because the process takes 20% of total jewelry manufacturing costs. The previous jewelry manufacturing process has many steps of "rough design${\leftrightarro}$ detailed drawing${\leftrightarro}$ wax pattern manufacturing ${\leftrightarro}$ lime soda flask mold manufacturing ${\leftrightarro}$ silver master pattern manufacturing ${\leftrightarro}$ mass production of wax pattern ${\leftrightarro}$ investment casting process ${\leftrightarro}$ final jewelry product." A novel process that reduces processing steps by using a rapid prototyping system (RP) has been suggested. The process is "3D CAD design ${\leftrightarro}$ DuraForm mold manufacturing by RP ${\leftrightarro}$ manufacturing master pattern by low melting alloy ${\leftrightarro}$ mass production of wax pattern ${\leftrightarro}$ investment casting process${\leftrightarro}$ final jewelry product." Molds are made with DuraForm powder, of which melting temperature is 19$0^{\circ}C$, by a selective laster sintering type RP. An alloy of Pb-Sn-Bi-Cd, of which melting temperature is $70^{\circ}C$, is casted in the DuraForm molds. Spheres and rings of diameter 20 mm are made by this process. The dimension deformation rate is less than 2%, and the post processing of the castings is convenient. The casting made by the suggested process can be used as a master pattern of jewelry products.of jewelry products.