• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.1-13
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• 2014

RP(Rapid prototyping) technology is widely used to reduce the cost and cycle time of new prototypes in industries as new product development cycle time currently shortened and the voice of customers also become to be diversified. In this study, RP skill used in making jewelry products was adapted to develop the metallic inlaying base of traditional handicraft products as the significance of CAD/CAM technologies was increased. The RP technology showed that it helped the handicraftsman to cut the groove for inlaying metalic wire more easily, uniformly and diversely than conventional handicraft technique in making the groove with undercut shape. Therefore this study showed that RP technology applied for the metalic inlaying base achieved more elaborate, intricate and uniform patterns, not depending on craftsmanship, compared with conventional handicraft skill in terms of quality, cost and delivery.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.69-76
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• 2014

Objective: This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods: Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of interexaminer and inter-method variability. Results: The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions: The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.590-592
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• 1997

Making physical models of human body is not only time-consuming but also very expensive since they are usually hand-made. This problem is doubled with implant fabrication because an implant is almost always custom-made. Recently, RP is emerging as an alternative, and many RP applications are proposed in the medical field. The major advantage of this approach is due to a significant reduction of both time and cost required or the production. However, the technology is not much in practical use yet, especially in Korea. In this paper, we provide a method of generating STL files that are the standard format to RP machines. The original data are obtained from two-dimensional slices of MRI/CT machine. Example bone models have been produced using a commercially available RP machine, and the results are presented.

• Composites Research
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• v.21 no.3
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• pp.18-23
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• 2008

The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, implantable Drug Delivery System (DDS) was fabricated by an RP system, Nano Composite Deposition System (NCDS). The DDS composite consists of 5-fluorouracil (5-FU), as drug particles, and PLGA85/15 as biodegradable polymer matrix. To have larger surface area, the DDS was fabricated in a scaffold shape, and its degradation was tested in vitro environment. Biocompatible Hydroxyapatite (HA) powders were added to the drug-polymer composite in order to control drug release. Test results showed a possibility of controlled release of scaffold DDS over 50 days.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.183-192
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• 2006

A CAD/CAM system has been developed for rapid prototyping (RP) of microfluidic devices based on excimer laser micromachining. The system comprises of two complementary softwares. One, the CAM tool, creates part programs from CAD models. The other, the Simulator Tool, uses a part program to generate the laser tool path and the 2D and 3D graphical representation of the machined microstructure. The CAM tool's algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD system, and process parameters (laser fluence, pulse repetition frequency, number of shots per area, wall angle), to automatically generate Numerical Control (NC) part programs for the machine controller. The performance of the system has been verified and demonstrated by machining a particle transportation device. The CAM tool simplifies part programming and replaces the tedious trial-and-error approach to creating programs. The simulator tool accepts manual or computer generated part programs, and displays the tool path and the machined structure. This enables error checking and editing of the program before machining, and development of programs for complex microstructures. Combined, the tools provide a user-friendly CAD/CAM system environment for rapid prototyping of microfluidic devices.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1021-1029
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• 2001

Rapid prototyping(RP) is a novel technology to create 3D products directly from CAD system. This study proposes a new RP method which uses the PZT ceramic plate to make a Drop-On-Demand liquid jet from the nozzle. The characteristic of drop formation in the new system is investigated both numerically and experimentally. The optimal drop for 3-D Printing can be obtained by the proper amplitude and frequency of the applied voltage. Also the process of the drop formation is analyzed using the pressure wave theory and verified by numerical simulation. First, the pressure wave generated by the deformation of the Piezo-plate at the nozzle is analyzed by solving the 2D axisymmetric wave equation via Finite Element Method. Finally, the drop formation process is simulated using a commercial software, FLOW 3D considering the pressure at the nozzle obtained by solving the wave equation as the boundary condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.5-8
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• 2003

This paper presents a methodology to be able to select an appropriate RP system that suits the end use of a part. Evaluation factors used in process selection include major attributes such as accuracy, roughness, strength, elongation, part cost and build time that greatly affect the performance of RP systems. Crisp values such as accuracy and surface roughness are obtained with a new test part developed. The test part is designed with conjoint analysis to reflect users' preference. The part cost and build time that have approximate ranges due to cost and many variable parameters are presented by linguistic values that can be described with triangular fuzzy numbers. Based on the evaluation values obtained, an appropriate RP process for a specific part application is selected by using the modified TOPSIS(Technique of Order Preference by Similarity to Ideal Solution) method. It uses crisp data as well as linguistic variables, and each weight on the alternatives is assigned by using pair-wise comparison matrix. The ranking order helps the decision making of the selection of RP systems.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.148-154
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• 2015

Computer aided process planning (CAPP) keeps an important role between the design and manufacturing engineering processes. A CAPP system is a digital link between a computer aided design (CAD) model and manufacturing instructions. CAPP have been researched and applied in manufacturing filed, however, one manufacturing area where CAPP has not been extensively researched is rapid prototyping (RP). RP is a technique for creating directly a three dimensional CAD data into a physical prototype. RP enables to build physical models automatically and to use to reduce the time for the product development cycle as well as to improve the final quality of the designed product. Three-dimensional (3D) printing is one kind of RP that creates three-dimensional objects from CAD models. The paper presents a computer aided process planning system for printing medical products. 3D printing has been used to solve complex medical problems such as surgical instruments, bioengineered products, medical implants, and surgical guides.

• Journal of Korea Foundry Society
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• v.21 no.5
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• pp.290-295
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• 2001

We fabricated test samples containing various shape elements and surface roughness checking points for the jewelry cast master patterns by employing the 3D computer aided design (CAD), selective laser sintering (SLS) rapid prototype (RP) with the DuraForm powders. We varied the alignment angle from $0^{\circ}$ to $10^{\circ}$ at a given layer thickness of 0.08 and 0.1mm, respectively, in RP operation. Dimensions of the shape elements as well as values of surface roughness are characterized by an optical microscope and a contact-scanning profilometer. Surface roughness values of the top and vertical face increased as the alignment angle increased, while the other roughness values and shape elements variation were not depending on the alignment angle. The resolution of the shape realization was enhanced as the layer thickness became smaller. The minimum diameter of the hole, common in jewelry design, was 1.2 mm, and the shrinkage became 12% at the 1.6 mm-diameter hole, Our results implied that we face down the proposed design elements with $0^{\circ}$ alignment angle, and consider the shrinkage effect of each shape element in DuraForm RP jewelry modeling.

• Korean Journal of Computational Design and Engineering
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• v.2 no.1
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• pp.35-43
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• 1997

Concurrent Engineering is one of the methods which are used for the rapid product development. One of the important features in Concurrent Egineering is that the development process is to be parallel and the organization should be cross-functional. In order that the process be parallel and that the organization be cross-functional, an integrated information system such as PDM (Product Data Management) is required. Although the integrated data base is constructed, it could be meaningless if the application softwares were not inter-operable. This study shows an example of intergrated information system from three-dimensional product design to mold design and tooling for the development of Deflection Yoke(DY) which is one of the important parts of Cathode Ray Tube(CRT). A three-dimensional product design software, which is based on a commercial code, has been developed by ourselves. Selective Laser Sintering(SLS), which is one of the rapid prototyping techniques, has been used in this study. Mold design has been done by the three-dimensional way. A newly developed method of mold tooling, which is called Quick Die Manufacturing(QDM), has been introduced.