• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.99-107
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• 2009

Since a long work piece influences the natural frequency of the entire system with a miniature high speed spindle, a bar-feeder is used for a long work piece to improve the vibration characteristics of a spindle system. Therefore, it is very important to design optimally support positions between a bar-feeder and a long work piece for a miniature high speed spindle system. The goal of the current paper is to present an optimization method for the design of support positions between a bar-feeder and a long work piece. This optimization method is effectively composed of the method of design of experiment (DOE), the artificial neural network (ANN) and the genetic algorithm (GA). First, finite element models which include a high speed spindle, a long work piece and the support conditions of a bar-feeder were generated from the orthogonal array of the DOE method, and then the results of natural vibration analysis using FEM were provided for the learning inputs of the neural network. Finally, the design of bar-feeder support positions was optimized by the genetic algorithm method using the neural network approximations.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1855-1866
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• 2003

This paper discusses an entire procedure for a robust controller design and its implementation of an AMB (active magnetic bearing) spindle, which is part II of the papers presenting details of system modeling and robust control of an AMB spindle. Since there are various uncertainties in an AMB system and reliability is the most important factor for applications, robust control naturally gains attentions in this field. However, tight evaluations of various uncertainties based on experimental data and appropriate performance weightings for an AMB spindle are still ongoing research topics. In addition, there are few publications on experimental justification of a designed robust controller. In this paper, uncertainties for the AMB spindle are classified and described based on the measurement and identification results of part I, and an appropriate performance weighting scheme for the AMB spindle is developed. Then, a robust control is designed through the mixed ${\mu}$ synthesis based on the validated accurate nominal model of part I, and the robust controller is reduced considering its closed loop performance. The reduced robust controller is implemented and confirmed with measurements of closed-loop responses. The AMB spindle is operated up to 57,600 rpm and performance of the designed controller is compared with a benchmark PID controller through experiments. Experiments show that the robust controller offers higher stiffness and more efficient control of rigid modes than the benchmark PID controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.6
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• pp.614-619
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• 2009

The STW(servo track writing) system which is the process of writing servo signals on disks before assembling in drives uses the spindle motor-chuck mechanism to realize low cost because the spindle motor-chuck mechanism has merit which can simultaneously write multi-disk by piling up disks in hub. Therefore, when the spindle motor-chuck mechanism of horizontal type operates in high rotation speed it is necessary to reduce the effect of RRO(repeatable run-out) and NRRO(non-repeatable run-out) to achieve the high precision accuracy of nano-meter level during the STW process. In this paper, we analyzed that the slip in assembly surfaces can be caused by the mechanical tolerance and clamping force in hub-chuck mechanism and can affect NRRO performance. We designed springs for centering and clamping considering centrifugal force by the rotation speed and assembly condition. The experimental result showed NRRO performance improves about 30 % than case of weak clamping force. The result shows that the optimal design of the spindle motor-chuck mechanism can effectively reduce the effect of NRRO and RRO in STW process.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.72-78
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• 2010

Textile machinery affects various industry, such as sport leisure industry, metal and chemistry material, electric electron, mechanical energy, packing and printing industry. In case of design of textile machine, the very important fact is absorbing the minute vibration induced by spinning thread and insert which is the part of spindle plays a role of reduction of impact caused by oscillation of thread bobbin. Therefore, Optimal design was executed by design of experiments and kriging optimal design methods to prevent fracture of spindle insert under the fatigue condition and deduced the best value of design parameter to improve the stability of the products. The highest sensitivity is showed at the design parameter A and D. As the spiral number of insert is increase, tension force applied its edge is distributed at whole model and the stress concentration is reduced.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.237-242
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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, heat flow and thermal deformation under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1767-1776
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• 2001

For the stable operation of high speed air spindle, the low rotational inertia and high damping ratio of spindle shafts as well as high fundamental natural frequency are indispensable. Conventional steel spindles are net appropriate for very high speed operation because of their high rotational inertia and low damping ratio. In this study, a high speed spindle composed of carbon fiber epoxy composite shaft and steel flange was designed for maximum critical speed considering minimum static deflection and radial expansion due to bending load and centrifugal force during high speed relation. The stacking angle and the stacking thickness of the composite shaft and the adhesive bonding length of the 7teel flange were selected through vibrational analysis considering static and thermal loads due to temperature rise.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.31-37
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• 2011

For the domestic glasses industry to procure competitiveness in the world CA(Cellulose Acetate) frame of spectacles market, CNC machining system for CA frame including high-value added CA cutting technologies should be developed with new materials for the rim based on Cellulose and sheet manufacturing base. The spindle system of glasses frame equipment that is the core to the quality of CA frame is the key technologies to realize high-speed, high-precision so its importance is remarkably emerging. In the study, at the structural design of the high spindle system of the private equipment for CA glasses frame embedded a motor of 40,000rpm, the stability of design was analyzed and investigated through selecting lubrication structure and thermal characteristics of the spindle system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.2
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• pp.166-171
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• 2015

In this study, an automation tool was developed for rapid evaluation of machine tool spindle designs with automated three-dimensional finite element analysis (3D FEA) using solid elements. The tool performs FEA with the minimum data of point coordinates to define the section of the spindle shaft and bearing positions. Using object-oriented programming techniques, the tool was implemented in the programming environment of a CAD system to make use of its objects. Its modules were constructed with the objects to generate the geometric model and then to convert it into the FE model of 3D solid elements at the workbenches of the CAD system using the point data. Graphic user interfaces were developed to allow users to interact with the tool. This tool is helpful for identification of a near optimal design of the spindle based on, for example, stiffness with multiple design changes and then FEAs.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.15-20
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• 2007

Recently the machine industry is rapidly advanced for improving productivity. Especially an effort decreased error factors of machine tool continuously is being studied. In this paper, we propose a method that decreased vibration in the high speed spindle. By appling 6-sigma technique(DMADOV), we can grasp the influence between the housing design and a rotation accuracy. For a correct conclusion, we measure an actual spindle and analysis by $ARMD^{(R)}$(rotation analysis program). inally we find out influenceable design factors and the improvement condition about 20.7%.