• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.221-226
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 50m/min using the high speed ball screw. Also, a lot of problems have happened the feed and servo drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed/accuracy control for feed/servo drive system of high speed/accuracy. In this study, we make use of high performance vertical machine center with a ball screw of large-scale-lead. Also, we'll apply the high-speed/accuracy control technology in this part of feedforward control, multi-buffering block size, etc. Using the design of the mechanical element and high-speed precision control, the basic design concept can be established.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.59-64
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• 2002

Recently the applications of high speed machining are increasing due to the need for high performance and high accuracy machining and machining for difficult-to-cut material. However, the high speed machining also accompanies some problems: the product quality can be degraded due to the tool wear and the product cast can go up due to frequent tool replacements. Therefore, it is necessary to develop a technique of quantitative tool wear measurement to determine the precise timing for tool replacement. In this respect, this study suggests a reliable technique far the reduction of error components by developing a system using a CCD camera and an exclusive jig to be able to precisely measure the size of tool wear in flat end mill for high speed machining.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.146-154
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• 2005

Recently, the high-speed and intelligence technology of machine tools are developed for the high efficiency of productivity Under the operating condition from the high-speed of machine tools, the various failure modes can occur in core units of manufacturing system. Therefore it is for the reliability concept of machine tool to be required in a design level. And the above-stated technology must be accommodated in the feeding and spindle subsystem, etc those are the core units of machine tools. In this study, we are developed the test-bed of sliding cover (C-plate) in order to evaluating reliability and estimating failure modes of feeding subsystem under operating conditions. The reliability experiment using the developed test-bed and the additional structural analysis executed on single and double structure. We found out the weak parts of sliding cover and were able to predict a life cycle from the experiment results. In this study, we propose the new C-plate model with double link structure to apply the high-speed machine tool in the fundamental guideline.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.528-535
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• 2002

In order to achieve high precision machine tools, the research for performance enhancement of feed drive systems is required. Development of the high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. Stick-slip friction has a great influence on the contouring accuracy of CNC machine tools. In this paper table levitation system has been developed for the stick-slip in a feed drive systems. And also, the driving position is set near the center of the main slideway. From the results, it is confirmed that yaw error and straightness can be improved.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.288-293
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• 2005

A earn profile grinding machine is a mandatory machine tool for manufacture of high precision contoured cam. Experimental evaluation of modal analysis is an effective tool to investigate dynamic behavior of a machine. This paper presents the measurement system and experimental investigation on the modal analysis of a grinding machine. The weak part of the machine is found by the experimental evaluation. The results provide structure modification data for good dynamic behaviors. And safety of the machine was confirmed by the modal analysis of modified machine design. Finally, the cam profile grinding machine was successfully developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.92-97
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• 1994

The there axis CNC grinding machine tool for ultra-precison mirror surface grinding of advanced materials such as ceramics and other hard and brittle materials was designed and manufactured. The grinding machine is composed of the air spindle, the high damping resin concrete bed, and the three axis CNC controller with the high resolution AC servo motor. To investigate the dynamic properties of the grinding machine, the natural frequencies of the spindle and the headstock were experimentally measured. The truing method using the break truer to revise the shape of the metal bonded diamond wheel was developed. Form the results of the machining using the prototype three axis CNC grinding machine manufactured, the mirror surface were achieved.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.171-178
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• 2002

With increasing the needs for micro and precision parts, micro machining technology using micro tools has been studied to fabricate a small part with high density such as electronics, optics, communications, and medicine industry more than before. Though these micro tools have developed rapidly, it is difficult to apply them to micro fabrication technologies, because of the inherent manufacturing. In this study, micro tools (WC) to produce micro structures and parts were manufactured by cylindrical grinding machine employing ELID (Electrolytic In-process Dressing) technique and the micro tools are fabricated as square shape with the dimension less than 100${\mu}{\textrm}{m}$. With the micro tools on the same machine, characteristics of micro grooving and drilling are evaluated. Also we compare normal micro machining with ultrasonic micro machining on the vibration table. It is confirmed that the developed micro tools are fully applicable to micro grooving, micro drilling and free form cutting.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.315-322
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• 2011

High-accuracy micropatterns such as V-shaped microgrooves are increasingly in demand for various engineering areas. And the technical trend goes for large surface areas in precision machining technology. So micropatterns with large surface areas are expected to play an increasingly important role in today's manufacturing technology In this study, we focused on developing machining technologies. First, a machine vision system for precise tool setting is developed. Second, an on-machine measurement (OMM) system for large-area measurement is implemented. And also software for tool path generation and simulation is developed. With these technologies we fabricated large-surface micropatterns in an electroless nickel-plated workpiece with single-crystal diamond tools and a 32-in, $675mm{\times}450mm$ mold with tens of V-and pyramid-shaped micropatterns.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.98-104
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• 2012

In this paper, precision processing is carried out for the pre hardened steel(HRC 54), which is one of injection mould materials. Processing characteristics are estimated according to the number of tool cutting blade and roundness is observed by the 3-Dimensional measuring machine. The surface roughness affected by the wire electric discharge machining are measured. Cutting component force of STAVOX is the highest in condition of 2F processing because load per a blade of cutting tool is high. Especially, the difference in Fz is over 20N by cutting load. The slower spindle rotation speed and tool feed rate are, the better cutting component force is. The roundness of hole processed in condition of 4F is good because feed rate is able to be fast. When rotation speed is increased, the surface roughness is decreased. The surface roughness acquired in condition of 2F processing is higher about 50% than 4F processing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.980-984
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• 2002

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verified the test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirm approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design.