• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.2
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• pp.52-60
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• 2004

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. High speed machine tool makers try to find best machining condition with the one that they have built. Machine builders need to develop test specimen since it helps finding characteristics o( machine tools when the machining properties of the specimen are analyzed. This paper develops test specimen to identify features of the main spindle, the feeding device, and the frame of a machine tool.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.498-501
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• 1999

Grinding machine rotating at high speed express the unbalance by the spindle and the weight of grinding wheel. Therefore, the parts requiring a precision processing for grinding machine need acutely to establish of automatic balancer. But the more wheel speed increases the more vibration amplitude increases, surface roughness show the satisfactory according to increase of the wheel speed. Surface roughness of the occasion installing the automatic balancer made better than an occasion no installing the automatic balancer.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.135-141
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• 2009

The bearing clearance is influenced by shrink fit and thermal expansion during operation. The designer must take into account the reduction of clearance after installation to the interference fits, and thermal expansion must be considered. The purpose of this study is to grasp the internal clearance variation and behavior of a bearing which is a deep connected with fatigue life of bearing and performance of spindle through FEM(Finite Element Method). Finite element analysis is performed by using commercial code ANSYS according to variation of thermal condition and rotational speeds. This paper presents correct negative internal clearance according to temperature during operation. Furthermore, interrelation between thermal expansion and contraction are presented to maintain adequate contact force for three type of spindle system (HSK-A60, HSK-40E, HSK-32E). The influence of the centrifugal force and Internal clearance variation of bearing is studied to operating rotational speed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.145-148
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• 2003

Thermal characteristics according to the bearing preload arc studied for the four type spindles with high frequency motor. For the analysis. three dimensional models are built considering heat transfer characteristics such as natural and forced convection coefficients, Bearing and motor are main heat generation, and heat generation by ball bearings as a function of load. viscosity and gyroscopic moment effect are considered. Unsteady-state temperature distributions and thermal displacements according to the bearing preload are analyzed by using the finite clement method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.182-183
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• 2008

In this study, rotor dynamic analysis have been conducted using three-dimensional solid model. Analysis object has smaller size and higher speed than any general CNC spindle. It is important to consider the real supporting conditions and external forces for whirl behavior analysis. As a results, the bearing stiffness is higher, whirl motion is less than before.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.429-434
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• 2001

This paper has been presented the dynamic effect by the journal speed, eccentricity and source positions in order to overcome the defects of air bearing such as low stiffness and damping coefficient. Choosing two row sources position of air bearing is different from previous investigations in the side of pressure distribution of air film by the wedge effects. An experimental study was performed to compare theoretical analysis. The dynamic stiffness was measured in actual cutting. It helps predicting of air spindle s characteristic in machining of die more precisely. The results of investigated characteristics was applied to air spindle for high speed milling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.553-556
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• 2003

End-milling have been used in the industrial world because it is very effective to the manufacture of mechanical parts with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in aircraft, automobile part and molding industry. Therefore this study carried to decide the optimum cutting condition for surface roughness and rapid manufacturing time using design of experiment and ANOVA. From the results of experimentation, surface roughness have an effect on cutting direction, spindle speed and depth of cut. And then the optimum condition used Taguchi design is upward cutting in cutting direction, 600rpm in spindle speed, 240mm/min feed rate, 2mm in axial depth of cut and 0.25mm radial depth of cut. By using design of experiment, it is effectively represented shape characteristics of working surface in end-milling.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.58-63
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• 2019

In this research, we examine the change of dimensional accuracy in the cutting process while changing cutting conditions such as feed rate and spindle rotational speed with chromium molybdenum steel (SCM415) material and TiCN- and TiAlN-coated end mill tools. According to dimensional accuracy measurement, TiCN-coated tool displays the most accurate dimensional tolerance at ${\varnothing}20mm$ at feed rates of 200 mm/min and 250 mm/min at a spindle rotation speed of 4,000 rpm. The largest dimension of the coating tool was able to make the TiAlN-coated tool suitable when comparing the smallest dimension.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.99-103
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• 1991

본 논고에서는 Radial 및 Axial 하중을 동시에 받을 수 있고, 예압에 의해 주축강성을 증대시킬수 있으며, Ball수의 증가로 부하능력을 향상시킨 초정 밀.초고속용 Angular ball bearing을 조합 사용하고, 고속회전에 지금까지 개 발된 ball bearing 윤활방법 중 가장 효과적인 간헐적인 oil 공급과 air 압력 으로, 계속 ball을 냉각, 윤활시켜주는 air oil 윤활법의 채용과, 국내 공작기 계 제조회사들이 주로 사용하는 일본 FAMUC AC Spindle motor(FAMUC-H type : 8000-15000rpm)를 사용해서 초고속 주축의 최적 설계조건을 제시하기 위한 기초연구 단계로 MT40-12000rpm 급의 Machining center용 Cartridge type의 Spindle unit개발을 통해서 주축설계에 따른 문제점과 연구용 주축제작의 생산 기술적 문제점 및 진동특성을 검토 하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.52-55
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• 1997

In this paper, the case study of reducing rotational errors is done for a grinding spindle with an active magnetic bearing system. The rotational errors acting on the magnetic bearing spindle are due to mass unbalance of rotor, runout, grinding excitation and unmodeled nonlinear dynamics of electromagnets. For the most case, the electrical runout of sensor target is big even in well-finished surface; this runout can cause a rotation error amplified by feedback control system. The adaptive feedforward method based on LMS algorithm is discussed to compensate this kind of runout effects, and investigated its effectiveness by numerical simulation and experimental analysis. The rotor orbit size in both bearings is reduced about to 5 pin due to lX rejection by feedforward control up to 50, 000 rpm.