• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.445-449
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• 2001

The tool wear that is developed by long-term machining in mold manufacturing with machining center makes a severe influence to the accuracy and the surface roughness. In this reason, tool-wear supervising system which has guaranteed high accuracy and high speed is needed to improve the measurement quality. Touching probe and touch sensor are widely used to measure the tool profile at on-machine measurement. In this paper, using the newly developed electric touch point measuring system, the Automatic Tool Compensation System is developed to correct the error of tool diameter resulted from the wear, and the operating method of this system is also provided.

• Design & Manufacturing
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• v.2 no.1
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• pp.27-31
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• 2008

The object of this study is a manufacture of buff die using CAM systems. Systems are consist of AutoCAD, CAM software and CNC milling machine. CAM software is purpose of G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for networking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1007-1010
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• 2002

The accuracy of high speed feeding type laser cutting M/C is the major factor directly concerned with the accuracy of the processed work, and the feed errors of feed system make the machining errors of work directly on processing. In this point, this study focused on the generative elements in feed errors of laser cutting M/C when operating its laser head. In order to improve the accuracy of this machining center, feed errors are measured by a laser interferometer.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.389-394
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• 2014

In this paper, we report a new manufacturing method for friction reduction using micro-AAJ (abrasive air-jet) machining. AAJ machining employs compressed air to accelerate a jet of high-speed particles to mechanically machine features, including micro-channels and micro-holes, into glass, metal, or polymer substrates for use in microfluidics, MEMS (micro electromechanical systems). And we introduce the micro-AAJ machining system, which consists of a micro-AAJ nozzle and a five-axis positioning system. Various micro-AAJ nozzles can be used, depending on the required surface structure, and three-dimensional machining is possible. We machined samples under six different conditions and describe machining results obtained while using it. We also measured the coefficient of friction of micro-textured surfaces. We report the coefficient of friction of micro-textured surfaces patterned using micro-AAJ machining for engine piston ring.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.375-381
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• 2004

Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modem production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.11-15
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• 2002

This paper presents the thermal characteristic analysis of a high-speed HMC with spindle speed of 50,000rpm. The spindle is supported by two radial and axial magnetic bearings. and the built-in motor is located between the axial and rear radial magnetic bearings. The X-axis and Y-axis feeding systems are composed of linear motor and linear motion guides, and the Z-axis feeding system is composed of servo-motor, ballscrew and linear motion guide. The thermal analysis model of high-speed HMC is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on the temperature distribution and thermal deformation under the conditions related to the heat generation of built-in motor, magnetic bearings, linear motors, servo-motor, ballscrew, and so on.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.33-40
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• 1997

Recently, there are an increasing needs for high speed rotating spindle which is an important mechanical ele- ment for a high efficiency machine tool in order to shorten machining time and cut production costs. The heat gen- eration is the most important problem in the motor integrated spindle. In this study, the effects of temperature distribution and thermal behavior according to the oil-air lubrication and cooling conditions are investigate theo- retically and experimentally on the motor-integrated spindle under unloading condition. The experimental spin- dle system is composed with the angular contact steel ball bearings, oil-air lubrication, air or oil jacket cooling system. To analyze the thermal behavior and cooling characteristics for the motor integrated spindle, the analysis using the finite element method is carried out. The analytical results are compared with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.459-467
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• 2016

Using a line scan camera and a Galvano mirror, we constructed a high-speed line-scanning microscope that can generate 2D images ($8000{\times}8000pixels$) without any moving parts. The line scanner consists of a Galvano mirror and a cylindrical lens, which creates a line focus that sweeps over the sample. The measured resolutions in the x (perpendicular to line focus) and y (parallel to line focus) directions are both $2{\mu}m$, with a 2X scan lens and a 3X relay lens. This optical system is useful for measuring defects, such as spalling, chipping, delamination, etc., on the surface of carbon fiber reinforced plastic (CFRP) holes after machining in conjunction with adjustments in the angle of LED lighting. Defects on the inner wall of holes are measured by line confocal laser scanning. This confocal method will be useful for analyzing defects after CFRP machining and for fast 3D image reconstruction.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.139-146
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• 2006

The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. For more quantitative analysis of a built-in motor's dynamic characteristics, that of tile mass and stillness effects are considered. And the drawbar in the spindle can be in various condition according to supporting stiffness between drawbar and shaft. Therefore, in this paper following items are performed and analyzed : 1. Modal characteristics of the spindle. 2. Analysis of rotor's mass and stiffness effects. 3. Modal characteristics of the spindle including drawbar, rotor and tool. The results show enough stiff supports must be provided between shaft and drawbar to prevent occurring drawbar vibration lower than the natural frequency of 1st bending mode of the spindle, and considering the mass and stiffness of built-in motor's rotor is important thing to derive more accurate results.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.441-446
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• 2001

This paper presents the thermal characteristics analysis of a high-speed HMC spindle system with angular contact ball bearings, built-in motor, oil-jet lubrication method, oil jacket cooling method, and so on. The spindle system is composed of the main spindle and sub-spindle which are mechanically connected by a flexible coupling. The spindles are supported by two front and rear bearings, and the built-in motor is located between the front and rear bearings of the sub-spindle. The thermal analysis model of spindle system is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on temperature distribution and heat flow under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.