• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.104-109
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• 2001

Nowadays, Industrial competition power is depended on that rapidly produce the customized products. Therefor, it is necessary to reduce period of product development. Thus, concurrent engineering that work many process at a time was appeared and Rapid prototyping was appeared, it is method that rapidly produce the prototype. If the graphic model was made by CAD, the prototype can be made in short term. That provide what the part was directly tested by the worker. It provide a worker with believable data. We study on the influence of surface roughness on injection interval and part angle at FDM.

• Korean Journal of Computational Design and Engineering
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• v.7 no.3
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• pp.148-156
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• 2002

Most Rapid Prototyping (RP) processes adopt a solid Computer Aided Design (CAD) model, which will be sliced into thin layers of constant thickness in the building direction. Each cross-sectional layer is successively deposited and, simultaneously, bonded onto the previous layer; and eventually the stacked layers from a physical part of the model. A new RP process, the transfer-type Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-ST), has been developed to reduce building time and to improve the surface finish of parts with the thick layers and a sloping surface. This paper describes the generation of Unit Shape Layer (USL), the cutting path data of the linen. hotwire cutter for the VLM-ST process. USL is a three-dimensional layer with a thickness of more than 1 mm and a side slope, and it is the basic unit of cutting and building in the VLM-ST process. USL includes data such as layer thickness, positional coordinates, side angles of each layer, hotwire cutting speed, the heat input to the hotwire, and reference shape. The procedure of generating USL is as follows: (1)Generation of the mid-slice from the CAD model, (2)Conversion of the mid-slice into a simply connected domain, (3)Generation to the reference shape for the mid-slice, (4)Calculation of the rotation angle of the hotwire of the cutting system.

• Polymer(Korea)
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• v.38 no.1
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• pp.93-97
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• 2014

Biodegradable drug-eluting stent has dual functions of supporting the lumen and treating internal tumor preventing the restenosis by releasing drug. In this study, the polycaprolactone (PCL) based three dimensional (3D) mesh loaded with paclitaxel (PTX) was presented by rapid prototyping (RP) technique of solid freeform fabrication (SFF) for biodegradable drug-eluting stent application. PCL has many advantageous properties such as good biocompatibility, good mechanical properties, and good drug permeability. PTX is widely used in the cancer treatment by inhibiting tumor cell proliferation. Analytical methods of HPLC and NMR were used for simultaneous quantification of PTX. Scanning electron microscopy (SEM) was performed to observe the architecture and morphologies of 3D mesh. The cytotoxicity assay results indicated released PTX's biological activity. This study provided that PCL based 3D mesh loaded with PTX by RP technique has great potential for biodegradable drug-eluting stent application.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.54-59
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• 2002

The principle of the FDM(fused deposition modeling) process is based on the layer by layer manufacturing technology, like other RP(rapid prototyping) process. In the FDM process, each layer may have different shape. Therefore, the built model may have stairs shape on its surface. This stairs shape is one of the serious problems in the FDM process. Thus in this study, cube models and spherical models were fabricated by FDM process to investigate the influence of injection amount on surface roughness. Models with various road width were also built to investigate the influence of road width on surface roughness. Surface roughness of the models was measured and analyzed. The result obtained in this study are expected to help selecting the part build orientation for optimum surface roughness.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.81-86
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• 1999

The STL file format is an approximation of 3-D model with triangular facets. STL is a standard input file format of Rapid Prototyping(RP) equipment. In computer graphics, a circle has been approximated with an inscribed polygon, which causes an error between the real and approximated circles. In this study, an intersecting polygon has been used to approximate the circle and applied to produce more accurate RP part. The newly proposed method shows it's excellence in part accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.87-94
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• 2002

Most of Rapid Prototyping (RP) process adopt a solid Computer Aided Design (CAD) model, slicing into thin layers of uniform, but not necessarily constant, thickness in the building direction. Each cross-sectional layer is successive1y deposited and at the same time, bonded onto the previous layers; the stacked layers form a physical part of the model. The objective of this study is to develop a method for calculating the rotation angle ($$\theta$_x, $\theta$_y$) of hotwire of the cutting system in the three-dimensional space for the Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-S). In order to examine the applicability of the developed method to VLM-S, various three-dimensional shapes. such as a screw, an extruded cross, and free surface bodies such as miniatures of the monkey(a figure of Sonokong), were made using the data obtained form the method.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.281-286
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• 2001

In this study, product design and prototype manufacturing of a plastic water-pump pulley has been tried. The designed model is supposed to be made of 33 % glass reinforced resin of which the tensile strength is 180 MPa, and has 24 ribs on each side to increase its structural strength. Structural analysis under a static load of 300 kgf acting on both edges of the belt has been carried out using a commercial finite element code, MARC. The analysis result showed the maximum effective stress near a rib of designed model would be at most 35 MPa (less than 20% of the tensile strength), therefore, the plastic product would be sufficiently safe under that loading condition. On the basis of the structural analysis, a prototype of the designed model has been manufactured by using the fused deposition modelling (FDM) method which is one of the rapid prototyping (RP) methods, using ABS resin and support materials. The CAD data exported to the RP system in STL format was prepared by a commercial solid modeling software, SolidWorks. It has been proved that the plastic pulley can successfully replace the existing flow-formed steel product.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.129-134
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• 1998

STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.3
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• pp.87-95
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• 2008

The purpose of this study is to provide a decision support to select an appropriate rapid prototyping(RP) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model for molding, material property, build time and part cost that greatly affect the performance of RP machines. However, the selection of a RP is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate RP machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify RP machines that the users consider. After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of RP machines.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.529-530
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• 2006

Manufacturing industry is changing rapidly. Prototyping with rapid manufacturing is a part of every business in many companies and prototypes are used efficiently as a part of the production development process. Sheet metal forming has traditionally been a technology area where prototyping has been extremely expensive and efficient options for low volume have been limited. This paper describes the process for incremental sheet forming technologies to make the prototype for a brake dust shield of vehicles, which includes the remodeling method to make a base mold and tool path for sheet metal forming and 5-axes laser cutting machine to trim the prototype product.