• International Journal of Precision Engineering and Manufacturing
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• 제4권3호
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• pp.62-67
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• 2003

The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed, depth of cut, on this parameter experimentally, Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).

• 한국정밀공학회지
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• 제15권8호
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• pp.26-32
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• 1998

The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed and depth of cut, on this parameter experimentally. Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1000-1004
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• 1995

In the case of the external cylindrical grinding machine, the grinding mechanism can cause a wheel to vibrate due to a wheel cutter. This phenomena will bring about the unsymmetric wear up to high frequency without any relation of rotational speed. So far, when the grinding spindle is analyzed, it is assumed that a wheel is considered as lumped mass at the endof a beam. Nowadays, there is a tendency to use the wheel with a lsrge diameter or CBN wheel to achieve the high speed and accuracy grinding performance. Therefore, this kind of assumption is no longer valid. At the analysis of the grinding spindle, the parameter which dapends on the dynamic characteristics is a combination force between each part. For example, there is the tightness torque of a bolt and taper element in the grindle. In addition, the material property of the wheel can contribute the dynamic characteristics. This paper shows the mode participation of the shell mode of the wheel in the grindle and the dynamic characteristics according to the parameters which are the configuration of the flange and tightness torque of a bolt and taper. Modal parameter of the wheel, flange and the spindle can be extracted through frequency response function obtained by modal test. After that, by changing the tightness torque and kinds of wheel, we could accomplish the test in the whole combined grinding spindle. To perform modal analysis of vibration characteristics in the grinding spindle, we could develop the model of finite element method.

• 한국정밀공학회지
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• 제18권7호
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• pp.106-111
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• 2001

This study reports the grinding characteristics of quartz. Grinding experiments were performed at various grinding conditions including wheel mesh, table speed and depth of cut. The grinding forces and specific grinding energies were measured. Surface roughness was also measured with tracer and the ground surfaces were observed with SEM. A new parameter SDR(Surface roughness Direction Ratio) is proposed to characterize the grinding mechanisms of quartz. A set of experiments was performed to verify the effectiveness of the suggested parameter. The experimental results indicate that the ductile mode is the dominant material removal mode at the grinding conditions which show the higher value of SDR whereas the material is removed by brittle fracture in a lower value of SDR value increases with wheel mesh size.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.3-7
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• 1995

Force generated during grinding process causes elastic defomation. The effect of this deforms a workpiecs. So grinding system is explainable using the concept of macining elasticity phenomenon. Machining elasticity is defined as ratio between the true depth of c ut, and an importnat factor to affect material removal mchanism and productivity. Generally, to produce accurate surface and dimensionally precise components operators depend on their experiences. Because of these, productivity is reduced and time is wasted. The objective of this reserch is to study the effect of grinding conditions, such as table speed, depth of cut on the machining elasticity parameter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.113-117
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• 1995

Grinding operations is accomplished by rotating a gfinding wheel with lots of random abrasive at high speed, and its object is generally obtained the fanal workpiece surface of high quality as well as the maximization of workpiece removal rate. But, especiallysince grinding operations is related with a large amount of functional parameter, it is actually difficult to therapy that the grinding trouble occurs during the grinding process. Therefore, we trytodesign grinding trouble-shooting system utilizing the back-propagation model of neural network. The conceptual method is produced byidentifying the four parameters derived from the grinding power, and we are design te to the grinding trouble-shooting system on the basis of their data. In this paper, cognition and therapy method tothe grinding trouble which utilizes neural network based four identified models are suggested, and implementation results of computer simulation with respect to the grinding burn and chatter vibration is presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.555-559
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• 1996

Based on the general drill grinding mechanism, termed the helical grinding system, the conceptual design of 5 axes CNC drill grinding machine is proposed. Unique determination of the grinding parameters for precise production of the desired flank geometry is discussed by utilizing a mathematical model. Also, different combinations of grinding parameters are mentioned in order to produce various drill geometries (conical, cylindrical, and planar drill) on the single proposed CNC machine. A manual helical grinding machine has been fabricated and consequently helical drills have been ground in order to check the feasibility of the proposed grinding mechanism and its functionality.

• 한국생산제조학회지
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• 제18권6호
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• pp.681-689
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• 2009

Disk grinding was often applied to deburring process in order to enhance the final product quality. Inherent chamfering capability of the flexible disk grinding process in the early stage was analyzed with respect to various process parameters including workpiece length, wheel speed, depth of cut and feed. Initial chamfered edge defined as arc zone was characterized with local radius of curvature. Averaged radius and arc zone ratio was well evaluated using neural network system. Additional neural network analysis adding workpiece length showed enhance performance in predicting arc zone ratio and curvature radius with reduced error rate. A process condition design parameter was estimated using remaining input and output parameters with the prediction error rate lower than 2.0% depending on the relevant input parameter combination and neural network structure composition.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.123-130
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• 2008

In order to clarify detailed mechanism of the flexible disk grinding system, workpiece length was introduced and its performance was evaluated. Flat zone ratio increased as the workpiece length increased. Increasing wheel speed and depth of cut also enhanced process performance by producing larger flat zone ratio. Neural network system was successfully applied to predict minimum depth of engagement and flat zone ratio. An additional input parameter as workpiece length to the neural network system enhanced the prediction performance by reducing error rate. By rearranging the Input combinations to the network, the workpiece length was precisely predicted with the prediction error rate lower than 2.8% depending on the network structure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.322-325
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• 2000

In the previous report1), the grinding characteristics of quartz were investigated. In this paper, the grinding mechanisms of brittle materials including ceramics and quartz are modeled and a new parameter SDR(Surface roughness Direction Ratio) is proposed to characterize the grinding mechanisms of such materials. A set of experiments were performed to verify the effectiveness of the suggested parameter. The experimental results indicate that the plastic deformation is the dominant material removal mode at the grinding conditions which show the higher value of SDR. In the case of quartz, the material was removed by brittle fracture in a lower value of SDR and by plastic deformation in a higher value of it. SDR is not affected by wheel mesh size when brittle fracture occured. But in the plastic deformation case, SDR value increases with wheel mesh size.