• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.35-42
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• 2008

By the reason of increased demand of high productivity and quality, the manufacturer have an effort in many directions of a machine tool industries. Among there, we proposed method of decreasing displacement in MC(machining center). In other words, Quality related with vibration of a tool cutting products. For decreasing it, improved by optimizing a shape of the column-part and acceleration curves of motors. In this paper we could find design factors has much influence on decreasing the displacement using the DOE(Design of Experiments) and optimized the level of the factors using $ADAMS^{(R)}$ and $MINITAB.^{(R)}$ And we suggest optimized a acceleration curve using $Matlab^{(R)}$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.47-51
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• 1992

Automatic detection of tool breakage during NC machining is a key issue not only for improving productivity but to implement the unattended manufacturing system. In this paper, we develop a vibration sensor-based tool breakage detection system for NC milling processes. The system obtains the time-domain vibration signal from the sensor attached on the spindle bracket of our CNC machine and declares tool failures through the on-line monitoring schemes. For on-line detection, our approach is to use the PSC(statistical process control) methods being increasingly used for on-line process control. The main thrust of this paper is to propose and compare the performance of SPC methods including : a) X-bar control scheme, b) S control scheme, c)EWMA (exponentially weighted moving average) scheme, and d) AEWMA (adaptive exponentially weighted moving average) scheme. The performance of the control schemes are compared in terms of the type 1 and 2 error calculated from the experiment data.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.230-235
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• 2000

In this paper, a surface generation model is presented to simulate surface roughness profile in turning operation. The simulation model takes into account the effect of tool geometry, process parameters, rotational errors of spindle, and the relative vibration between the cutting tool and workpiece. The surface roughness profiles are simulated based on the surface-shaping system. The model has been verified by comparing the experimental values with the simulation values. It is shown that the surface simulation model can properly predict the surface roughness profile.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1011-1017
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• 2011

Servo control loops are a core part in the control architecture of machine tools. Servo control loops manage acceleration, velocity and position of all the axes in a machine tool based on commands. The performance of servo control loops sets the basis for quality of production paris and cycle time reduction. First, this paper presents a general control architecture of machine tools and several control schemes in literature, which can be applicable to machine tools control; including Zero Phase Error Tracking Control (ZPETC) and Cross Coupling Control (CCC). After that, modem control strategies to mitigate the problem of high speed machining are reviewed. In high speed machining, high accelerations excite the machine structure up to high frequencies, thereby exciting the structure's modes of vibration. These structural vibrations need to be damped if accurate positioning or trajectory following is required. Input shaping is an attractive option in dealing with structural vibrations. The advantages and drawbacks of using input shaping technique for machine tools are discussed in detail.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.179-184
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• 2003

Noise cause is dividing to fluid noise by exhaust flow of fm and vibration noise by rotational vibration of motor. Until now, measuring method has been used to measure vibration by the accelerometer, this method has been not measured for the vibration in some parts of brush and commutator because of motor construction. This research was purposed on the accurate analysis, using laser vibration analyzer, of noise cause against the difficult part in old times. By using this measured data, we would like to use for the design of silent motor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.316-321
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• 1997

The purpose of this study is to reduce the vibration noise of differential gear by reducing torque fluctuation of drive pinion shaft which causes vibration noise of differential gear in rear wheel drive vehicles. For this we developed multi-degree of freedom analysis model in which mass moment of inertia and torsional spring combined, the validity of the simulation model was checked by the field test and we examined the influence of torsional vibration of driveline elements by performing forced vibration analysis of engine excitation torque. We studied the methods for reducing torsional vibration of driveline according to the design factor of propeller shaft and examined the effects reducing vibration differential gear by applying flexible coupling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1096-1101
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• 2000

In machine tools, often a gearbox is installed to control the rotating speed of spindle, which sometimes generates problems of noise and vibration due to errors in tooth-meshing. In this study, the characteristics of, noise and vibration of given gearbox for a machine tool are analyzed experimentally. From the measurement, it was observed that the tooth-meshing component of the sound pressure level from the gearbox took its maximum at a specific operational speed. Therefore, the main content of this study is to investigate the reason why the above mentioned characteristics are observed. By investigating the natural frequencies of the components in gearbox, it was found that the natural frequencies of the rotating gear-shaft and gearbox for twisting mode were closely related to the first and second peak of sound pressure levels respectively. Thereform, in this study, those relations were identified by the impact test of rotating gear-shaft and-gearbox. In addition, we inserted the rubber between housing and bed, and analyze the effect of the rubber insertion on noise reduction by Operational Deflection Shapes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.142-147
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• 2012

Machining tool conditions directly affect to quality of product and productivity of manufacturing. Many researches performed for tool condition monitoring in machining process to improve quality and productivity. Conventional methods use characteristics of signal for cutting force, motor current consumption, vibration of machine tools and machining sound. Recently, diameter of machining tool is become smaller for minimizing of mechanical parts. Tool condition monitoring using conventional methods are relatively difficult because micro machining using small diameter tool has low machining load and high cutting speed. These days, the direct monitoring for tool conditions using vision system is performed actively. But, vision system is affected by external conditions such as back ground of image and illumination. In this study, minimizing technology of external conditions using distribution analysis of image data are developed in micro machining using small diameter drill and tap. The image data is gathered from vision system. Several sets of experiment results are performed to verify the characteristics of the proposed machining technology.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.457-462
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• 2002

This paper describe the vibration characteristics of cantilevered beam filled with ERF subjected to variousr electrode charge. The Proposed ER fluids used in the present study consists of starch particles and silicon oil. The ER fluids undergo a phase-change when subjected to an external electric filed. This Paper Presents performance analyses of three types of the cantilevered beam with different electrode gaps and applied electric fields.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.114-119
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• 1997

Natural vibration of the rotor system having multi-step cross-sections is analyzed. The rotary inertia and the shear deformation are considered. Torque is also included in order to simulate the power transmission system. The complex displacement and the variable separation are introduced. The exact solutions in uniform cross-section segment and the boundary conditions are used. Natural frequencies and mode shapes are obtained, especially the mode shapes are countinuous.