• Korean Journal of Computational Design and Engineering
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• v.8 no.3
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• pp.157-166
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• 2003

In this paper, we explain the DMU (digital mockup) system based on the PDM system. Most manufacturing companies are trying to develop a competitive product by increasing the quality, shortening time to market (TIM) and reducing the cost of a product. Some technologies such as SE (System Engineering), CE (Concurrent Engineering), QFD (Quality Function Development), CI (Cost Innovation) and some systems such as CAD (Computer-Aided Design), CAE (Computer-Aided Engineering), CAM (Computer-Aided Manufacturing), PDM (Product Data Management) and visualization system are adopted for these purposes. Specially, DMU system utilizes a visualization system that shows the 3D shape of a product on the computer and it gives a quick intuition to a person whether he/she is an engineer or not. It also can induce the effects of CE and QFD. SO, 0 company is developing a DMU system integrating CAD, visualization and PDM system. The main feature of the developed DMU system is that it is entirely integrated with PDM system, which means that the 3D shape of any part or assembly can be retrieved through PDM system. The DMU system will change the development process, which will increase the competitiveness of a developed product.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.267-274
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• 2002

Using a flexible rotating beam test bed, experimental verification of a flexible multibody dynamic simulations for a rotating beam model has been carried out. The test bed consists of a flexible arm, harmonic driver reducer, AC servo motor and DSP board with PC. The mechanical ports of the test bed has been designed using 3D CAD program. For the simulation model, mass and moment of inertia of each part of the flexible rotating beam test bed are also obtained from 3D CAD model. In the flexible multibody dynamic simulations, the substructuring model has been established to capture nonlinear effects of the flexible rotating beam. Through the experimental verification, substructuring model provides better results than those from the linear model in the high speed rotation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.2 s.257
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• pp.260-268
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• 2007

Demand for the use of 3D CAD DMU systems over the Internet environment has been increased. However, transmission of commercial 3D kernels has delayed the communication effectiveness due to the kernel size. Light weight CAD geometric kernel design methodology is required for rapid transmission in the distributed environment. In this paper, an assembly data structure suitable for the top-down and bottom-up assembly models has been constructed. Part features are stored without a hierarchy so that they are created and saved in no particular order. In particular, this paper proposes a new assembly representation model, called multi-level assembly representation (MAR), for the PDM based assembly DMU system. Since the geometric kernel retains assembly hierarchy and topological information, it is applied to the web-viewer for the PDM based DMU system. Effectiveness of the proposed geometric kernel is confirmed through various case studies.

• IE interfaces
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• v.13 no.2
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• pp.157-165
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• 2000

In this paper, an efficient method is proposed to place the cooling lines(CLS) and ejector pins(EPS) of mold design. The other components of mold, except CLS and EPS, can be generated automatically by batch processing. But the placements and sizes of CLS and EPS depend on the shapes of a part, so that the design works of CLS and EPS should be processed interactively. Using the pre-defined reference points, the positions of CLS and EPS can be determined interactively. By the proposed method, the interference occurred during placing CLS and EPS can be avoided, and the proper lengths of them can be calculated automatically. The information of the positions and lengths are stored in BOM database for generating a machining data. The proposed method is implemented with Unigraphics API functions and C language, tested on Unigraphics V15.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.47-53
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• 2018

Nowadays, additive manufacturing (AM) technology is a promising process to fabricate complex shaped devices applied in medical and dental services. Among the AM processes, a DLP (digital light processing) type 3D printing process has some advantages, such as high precision, relatively low cost, etc. In this work, we propose a simple method to fabricate precise dental models using a DLP 3D printer. After 3D printing, a part is commonly post-cured using secondary UV-curing equipment for complete polymerization. However, some shrinkage occurs during the post-curing process, so we adaptively control the UV-exposure time on each layer for over- or under-curing to change the local shape-size of a part in the DLP process. From the results, the shrinkage amounts in the post-curing process vary due to the UV-dose in 3D printing. We believe that the proposed method can be utilized to fabricate dental models precisely, even with a change of the 3D CAD model.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.1
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• pp.7-16
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• 2004

The tool path needs to be determined in an efficient manner to generate the final NC (numerical control) code for efficient machining. This is particularly important in machining free form pockets with an arbitrary wall geometry on a three-axis CNC machine. Many CAD/CAM systems use linear interpolation to generate NC tool paths for curved surfaces. However, this needs to be modified to improve the smoothness of the machined bottom surface, reduce machining time and CL (cutter location) file size. Curved machining can be a solution to reduce these problems. The unified rough and finish cut algerian and the tool motion is graphically simulated. In this paper, a grid based 3D navigation algorithm for generating NC tool path data for both linear interpolation and a combination of linear and circular interpolation for three-axis CNC milling of general pockets with sculptured bottom surfaces is developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.836-839
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• 2004

Qualitative elevation of products is very important Part. A business racking us brains to find for qualitative elevation of products. Recently, measurement accuracy of a non-contact 3D scanner has been rapidly improving. As a result, the number application cases of non-contact 3D scanners are increasing. A non-contact 3D scanner is capable of measuring a curved surface rapidly and has high resolution. It is more affordable and potable than the CMMs, It is therefore expected to be applied more frequently in more diverse industries. Automating the measuring process using a non-contact 3D scanner and developing a technology, which allows a user to measure easily, will eventually improve the quality of products. As their inspection and analysis processes improve.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.352-356
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• 2002

In this paper, an automated design system of suspension and steering parts is developed. The system automates the processes of 3-D modeling and 2-D drafting of the parts. In addition, the BOM and dimension data of the designed part is also automatically transferred to the database of ERP system. The system is developed by using the functions of parametric design and API(application Programming Interface) of the a commercial solid modeler.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.64-71
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• 2011

Construction projects are becoming larger in size and higher in complexity. Operation and maintenance, therefore, is an important part in providing the serviceability of the built facility from the perspective of life-cycle. This paper presents a 3D graphic model-integrated data extraction for bridge maintenance. The 3D graphic model environment assigns attributes to the member blocks in CAD, and link the attributes to the data stored in a database. Then, the user can click the member block to extract the data associated with the attributes. A prototype has been developed to test the applicability of the 3D graphic model environment using CAD and web. Application of the system in an actual bridge construction showed that the 3D graphic model environment can help the user find necessary data at a shorter time, thereby increasing the effectiveness of operation and maintenance in bridge structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.566-569
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• 2002

Rapid Prototyping is a prototyping technology that produces complicated parts directly form three dimensional CAD data with high efficiency, and has been extensively applied to various manufacturing processes. The aim of this research is to apply a 3D printer part as wax pattern in the investment casting process. The difference between conventional pattern wax and 3D printer wax is compared by experiments. The direct casting method is developed for ceramic-shell investment casting.