• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.2
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• pp.1-10
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• 2000

With every passing month a number of new virtual enterprises emerge on the internet. Many companies have responded to the idea of distributed manufacturing in which the value adding activities comprising a finished product are dispersed geographically in a remote place. This study suggests an idea for selecting suppliers in a distributed manufacturing environment which enables machining companies to share their capacities. A mathematical model is constructed to show how to minimize the sum of the operation and transportation costs based on alternative process plans considering several kinds of operation characteristics in the real world. Four heuristic algorithms are developed to get an optimal or near-optimal solution using tabu search since the model is proven NP-hard. Example problems are tested to illustrate their procedure and performance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.456-461
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• 2002

Nowadays, there are required more speed and accurate machining in order to improve the productivity through the reduction of cutting and non-cutting time. In this study, the high-speed HMC is specially designed to do remote control and high-speed mechanism with 30000rpm, 50000rpm, 40m/min, 100m/min and bridge type structure. Every structural deformation and vibration that is generated from all of factor is analyzed being based on the virtual manufacturing technologies: thermal characteristic analysis, machine-ability, tool wear measuring system, driving characteristic of linear motor and so on. As the application of these results had been consisted of three axes to move slight and rigid finally. Therefore, table errors that are resulted in change of work weight can be removed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.68-72
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• 2004

A practical method to investigate the user interface of web based Flexible Manufacturing System(FMS) on the internet environment is established. Because the industrial FMS controller requires a lot of gadget, such as switch, dial, button, etc., for actual work-site flexible operation sufficiently, the user interface of the controller is significantly complex. The support for operational convenience of FMS controller can increase productivity and efficiency of the user, operational personnel of FMS. While most FMS provide their application programming interface(API) and graphical user interface(GUI) with adequate mechanism itself when used in stand alone, there is increasing demand for FMS that can operate with the intuitional user interface find virtual reality(V/R) environment. This thesis considers the intuitional user interface of Web-based FMS first, and from this, goes a step further, improves as virtual reality environment of FMS on the internet environments by using the feature based modeling technique approach and cartoon rendering. The feature-based modeling technique approach is applied to FMS line which is consist of facilities such as machining center, CNC lathe, autonomous guided vehicle, rail guided vehicle, and various controllers. In this study, the FMS established the intuitional user interface is able to obtain not only the operational convenience but also the enough productivity and significant efficiency.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.785-791
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• 2005

Reconfigurability of machine tools is one of the critical factors to realize the responsive manufacturing systems to satisfy the mass-customization production. This paper presents the methods to model and simulate the machine tools on Internet in response to change in the machining requirements. Specifically, a set of module combination rules and a modeling method of the structure of machine tools using connectivity graph are developed. In response to the user requirements, kinematic relations and structures of machine tools can be derived using the module combination rules and connectivity graph relationships. Internet-based simulator of machine tools is implemented and presented. The developed machine tool simulator can be used to verify the structure of machine tools derived from the user requirements.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.90-95
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• 2005

To perform the finish outside-diameter grinding process of ferrules which are widely used as fiber optic connectors, a high-precision centerless grinding machine is necessary. In this study, the thermal characteristics of the high-precision centerless grinding machine such as the temperature distribution, temperature rise and thermal deformation, are estimated based on the virtual prototype of the grinding machine and the heat generation rates of heat sources related to the machine operation conditions. The reliability of the predicted results is demonstrated by the temperature characteristics measured from the physical prototype. Especially, the predicted and measured results show the fact that the high-precision centerless grinding machine consisted of the hydrostatic GW and RW spindle systems, hydrostatic RW feeding mechanism, RW swivel mechanism, on-machine GW and RW dressers, and concrete-filled steel bed, has very stable thermal characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.151-159
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• 2006

This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data f3r fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data for machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used for virtual cutting test and analysis as well.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1634-1641
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• 2006

High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a sensitivity analysis for structural and thermal characteristics was carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW table feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The results of the structural sensitivity analysis illustrated that the vertical stiffness of hydrostatic guideway for the RW table feed system greatly influenced the horizontal loop stiffness, and the results of the thermal sensitivity analysis illustrated that the heat generation rates at hydrostatic bearings and belt pulley greatly influenced the temperature rise of hydrostatic bearings and the deviation of thermal displacement between GW and RW.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.456-463
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• 2005

This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data fur fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data fer machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used fur virtual cutting test and analysis as well.

• Journal of Conservation Science
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• v.35 no.3
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• pp.217-225
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• 2019

The chimi(ridge-end tile) of Wangheungsa temple is the oldest in our country. The upper part of the chimi was excavated from the southern side of Wangheungsa temple and the lower part from the northern side. These parts are considered to be portions of the same chimi, because they are similar in shape and are excavated from two sides of the same temple structure. However, the original shape of the chimi cannot be determined owing to substantial deterioration. Hence, in this study, replicas of the deteriorated chimi portions of Wangheungsa temple were fabricated by employing 3D scanning technology and the computer numerical control machining method. While observing the bending phenomenon of the chimi, the proposed model was warped realistically on the basis of the bending direction of the actual chimi. Consequently, the restoration process was modified several times. The results indicated that no gaps can be found between the upper and lower parts, and the corresponding patterns connect naturally. Furthermore, the proposed method is contactless, safe, operable, reproducible, and appropriate for restoration of artifacts. Additionally, the modeling data is semi-permanent. Hence, if modelling data is appropriately applied as per the characteristics of artifacts, it can be utilized in various fields such as virtual exhibitions, hands-on exhibitions, cultural heritage restoration, and production of teaching aids and souvenirs.