• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.884-889
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• 1994

In this work, rapid prototyping and three dimensional finite element analysis are simltaneously applied to design metal forming processes. Rapid prototyping is a new prototyping technology which producess three dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus (SLA) which is the most widely-used rapid prototyping system is introduced to manufacture the die set. To prepare STL file generally, mesh data which are in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are effectively connected. The die sets are manufactured using SLA prototypes, and matal forming experiments are carried out using them. Comparing experiments results with analyses, the processes can be predicted and designed successfully.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.245-246
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• 2006

For developing 5-axis laser cutting systems, many problems such as rotating of laser head or table, 5-axis tool path generation and collision avoidance between laser head and product should be solved. In this paper, a five-axis laser cutting machine with table swivel and rotary type configuration is developed. The five axes (X,Y,Z,A,B) are controlled and interfaced to PC via MMC board. Two kinds of CAM S/W such as commercial 5-axis CAM S/W(Euclid) and UG-API are engaged to generate NC code for the developed 5-axis laser cutting machine.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.118-127
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• 2003

An effective tool management system is one of the keys to maximizing the benefits of a computer integrated manufacturing (CIM). Tool management systems, however, are often tailored to the requirement of a highly automated system. Therefore, a different approach is needed for small and medium sized mold shops. This work deals with the implementation of tool management system for milling operations in small and medium sized CIM environment of injection mold production. In this paper, a distributed management approach is proposed for efficient tool management in relatively small machining shops in mold industry. And the design and the functions of the developed system are described.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.664-669
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• 1994

This paper focuses on development and implementation of a performance management algorithm for IEEE802.4 token bus networks to serve large-scale integrated manufacturing systems. Such factory automation networks have to satisgy delay constraints imposed on time-critical messages while maintaining as much network capacity as possible for non-time-critical messages. This paper presents a network perfomance manager that adjusts queue apacity as well as timers by using a set of fuzzy rules and fuzzy inference mechanism. The efficacy of the performance management has been demonstrated by a series of simulation experiments.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.3
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• pp.50-53
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• 2007

Improving the reliability or long-term dependability of a system requires a different approach from the previous emphasis on short-term concerns. The purpose of this paper is to present a reliability evaluation method for an oil cooler intended for high-precision machining centers. The oil cooler system in question is a cooling device that minimizes the deformation caused from the heat generated by driving devices. This system is used for machine tools and semiconductor equipment. We predicted the reliability of the system based on the failure rate database and conducted the reliability test using a test-bed to evaluate the life of the oil cooler. The results provided an indication of the reliability of the system in terms of the failure rate and the MTBF of the oil cooler system and its components, as well as a distribution of the failure mode. These results will help increase the reliability of oil cooler systems. The evaluation method can also be used to determine the reliability of other machinery products.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.73-81
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• 1991

There have been many studies on chatter vibration in machining but there seems to be no regulations to decide the commencing point of chatter objectively. The development of an objective method which can estimate and detect chatter commencement is very much in need for automatic manufacturing systems, dynamic performance tests for machine tools, so on. In this study, therefore, the estimation and the in-process detection of chatter have been experi- mentally investigated for the turning process. As a result, the commencing point of chatter can be decided from the behavior of the maximum amplitude of the dynamic component of cutting force, where the maximum amplitude is suddenly increasing with the chatter commencement. Then the commencing point of chatter can be estimated practically by this method before the occurrence of excessive vibration. Also, it is possible to detect the occurence of chatter vibration through the in-process measurement, by monitoring the maximum amplitude of the dynamic component of cutting force.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.6
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• pp.61-70
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• 2003

A multibody system dynamics analysis program is presented using one of the most useful programming methodologies, the object-oriented modeling, The object-oriented modeling defines a problem from the physical world as an abstract object. The object becomes encapsulated with the data and method, Analysis is performed using the object's interface, It is then possible for the user and the developer to modify and upgrade the program without having particular knowledge of the analysis program, The method presented in this paper has several advantages, Since the mechanical components of the multi-body system are converted into the class, the modification, exchange, distribution and reuse of classes are increased. It becomes easier to employ a new analysis method and interface with other S/W and H/W systems, Information can be communicated to each object through messaging. This makes the modeling of new classes easier using the inheritance, When developing a S/W for the computer simulation of a physical system, it is reasonable to use object-oriented modeling.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2152-2154
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• 1999

In this paper, we suggested the design rule of high-voltage rectangular waveform generator working in low frequency domain (5Hz $\sim$ 60Hz). Most of the commonly used power electronic switching devices have voltage ratings up to several kV. So it is difficult to design and fabricate high-voltage switching systems with the power electronic devices alone. We have combined IGBTC(1200V, 50A) with the specially designed transformer to get the high-voltage rectangular waveforms up to 40kV. In this work. next two things are the main factors. The first one is design of transformer working low-frequency domain close to 5Hz. And the second one is additional voltage source to floating the transformer voltage output. As a result, we can get frequency-variable and high-voltage rectangular voltage waveform and this can be a more efficient power source of sandpaper manufacturing process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.253-266
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• 1998

The purpose of this study was to analyze the difference in logistics information system and indirect effects of logistics performances on the acceptance level of logistics information system. The limitation and recommendation of this study were as follows : First, as the history of logistics introduction in Korean corporations is short, the level of logistics information system sampled in this study is very low. So the findings of this study is hard to represent the general logistics information system situation of in Korea our corporations. Second, the focus of this study is on the manufacturing corporations, so the study on the logistics corporations is required. And the study on the effects of firm's situation(formalization, decentralization, concentration, strategic plans) on the characteristics of logistics information system is needed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.21
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• pp.73-79
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• 1990

The quality and cost of manufacturing products is a significant problem in view of duality assurance, but the quality level of the incoming materials is not considered to determine in the economic order quantity of conservative inventory model. A typical situation we face is the difference of quantity between order quantity and the determined outgoing quantity after acceptance inspection. In this paper we present a procedure to reduce the difference of order(ingoing) quantity and outgoing quantity of incoming materials a method of justifying the acceptance plans whether accept or not by comparing with ingoing outgoing quality.