• 한국공작기계학회논문집
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• 제13권5호
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• pp.30-37
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m／min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• 한국기계가공학회지
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• 제1권1호
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• pp.79-88
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• 2002

High speed machining system have been used in industrial because it is effective to a material manufacturing 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 proposed to decide best manufacturing cutting condition for surface roughness and rapid manufacturing tune by using computer Image processing system and 3D modelling. Until the 16,000 rpm, the surface roughness is decreased rapidly, but it is not over that. The 22,000 rpm is the spindle speed with the optimum surface in the high speed end-milling. In the case of the feed rate with 2,000 mm/mm and 8,000 mm/mm, the surface roughness is better than 4,000 mm/min and 6,000 mm/min. By using the 3D modelling, it is effectively represented shape characteristics of working surface m high speed end-milling.

• 한국기계가공학회지
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• 제14권4호
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• pp.160-166
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• 2015

Ultrasonic machining (USM) has been considered a new, cutting-edge technology that presents no heating or electrochemical effects, with low surface damage and small residual stresses on brittle workpieces. However, nowadays, many researchers are paying careful attention to the disadvantages of USM, such as low productivity and tool wear. On the other hand, in this study, a high-performance rotary ultrasonic drilling (RUD) spindle is designed and assembled. In this system, the core technology is the design of an ultrasonic vibration horn for the spindle using finite element analysis (FEA). The maximum spindle speed of RUM is 9,600 rpm, and the highest harmonic displacement is $5.4{\mu}m$ noted at the frequency of 40 kHz. Through various drilling experiments on glass workpieces using a CVD diamond-coated drill, the cutting force and cracking of the hole entrance and exit side in the glass have been greatly reduced by this system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.788-791
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• 2004

This paper presents a general description of single and dual contact tooling systems, finite element analysis, and discussions on the application of the system to the 5-head router machine which is in particular for aerospace components. This study has been performed as part of the development of the new generation 5-head router machine which is designed for high productivity. Such high productivity in essence requires high speed rotation and multiple spindles in one machine. The high speed rotation may exceed a range in a conventional single contact tooling system. The conventional tooling system is reevaluated in comparison with the dual-contact system. Finite element analysis using simplified spindle models compares major differences in the two systems. Some problems in the application to the 5-head router machine are discussed.

• 산업경영시스템학회지
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• 제27권2호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.439-440
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• 2009

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.437-438
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• 2009

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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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.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.1-7
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• 2006

By the reason of increased demand of high productivity, the researches on manufacturing process and equipments for reducing cycle time have been made in many directions of a machine tool industries. Especially high productivity is very important to machining center with high-speed spindle. This paper proposed method of reducing T-T(tool to tool) time which results in shorter unclamping time. T-T time varies as factors such as a hydraulic system, a drawbar mass, a flow meter, a disc spring, piston and pipe diameters. In this paper We could find design factors has much influence on decreasing the unclamping time using DOE(Design of Experiment) and optimized the level of the factors using AMESim $4.0^{(R)}$ and visualNastran $4D^{(R)}$ Finally, we have verified improved result of the optimized factors with initial design.

• 한국정밀공학회지
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• 제26권5호
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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.