• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.703-707
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• 2000

Machine tool errors have to be characterized and predicted to improve machine tool accuracy. A real-time error compensation system has been developed based on volumetric error synthesis model which is composed of machine tool errors. This paper deals with new algorithm about verification of machine tool errors. This new algorithm uses a simplified volumetric error synthesis model. This simplified model is constructed with only main components among the error components of the machines. This main error components are analyzed by three-dimensional helical ball bar test. By substituting result of helical ball bar test fer simplified model, we could find that obtained error components are closed to real error components.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.143-151
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• 2001

Machine tool errors have to be characterized and predicted to improve machine tool accuracy. A real-time error compensation system has been developed based on volumetric error synthesis model which is composed of machine tool errors. This paper deals with new algorithm about verification of machine tool errors. This new algorithm uses a simplified volumetric error synthesis model. This simplified model is constructed with only main components among the error components of the machine. The main error components are analyzed by ball bar test of hemispherical helix. The novel measurement method using ball bar system has many advantages which are more efficient, easier to use than conventional measurement system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.28-34
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• 1999

The objective of this study is to estimate and to compensate far the volumetric error of a workpiece influenced by the geometric error of a machine tool. In this paper, the volumetric error is defined and the error synthesis model is presented. Then, the volumetric error of workpiece is calculated and compared through the simulation, and a new tool-path is generated to compensate for the error in the post-processor of CAM system using the error synthesis model. By this method, the error is compensated without modification or replacement of a machine tool being in use.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.134-139
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• 1998

The objective of this study is to estimate and to compensate for the volumetric error of a machine tool. In this paper, the volumetric error is defined and error synthesis model is presented. Then, the volumetric error of workpiece is compared through the virtual machining and a new tool-path is generated to compensate for the error in the post-processor of CAM system using the error synthesis model. By this method, the error is compensated without modification or replacement of a machine tool being in use.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.122-129
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• 1999

A 5-axis CNC machine tool is more useful compared with a 3-axis machine tool, because the position and the orientation of a tool tip can be controlled simultaneously. Unlike the 3-axis machine tool, the 5-axis machine tool has the volumetric position error and volumetric orientation error due to the quasi-static error of each machine tool joint which is a major source of machined part error. So, the generalized error synthesis model of the 5-axis CNC machine tool was developed to predict and to compensate for the volumetric position error and the volumetric orientation error. It was proposed that a compensation algorithm to correct simultaneously the volumetric position error and the volumetric orientation error of the 5-axis CNC machine by error inverse kinematic.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.67-75
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• 1998

Geometric and thermal errors are key contributors to the errors of a computer numerically controlled turning center. A planar error synthesis model is obtained by synthesizing 11 geometric and thermal error components of a turning center with homogeneous coordinate transformation method. This paper shows the sensitivity analysis on the temperature change, the confidence evaluation on the uncertainty Of measurement systems, and the error contribution analysis from the planar error synthesis model. Planar error in the z direction was very sensitive to the temperature change. and planar errors in the x and z directions were not affected by the uncertainty of measurement systems. The error contribution analysis ,which is applicable to designing a new turning center, was helpful to find the large error components which affect planar errors of the turning center.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.507-512
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• 2013

This paper proposes a new model to compensate for errors of a five-axis machine tool. A matrix with error components, that is, an error matrix, is separated from the error synthesis model of a five-axis machine tool. Based on the kinematics and inversion of the error matrix which can be obtained not by using a numerical method, an error compensation model is established and used to calculate compensation values of joint variables. The proposed compensation model does not need numerical methods to find the compensation values from the error compensation model, which includes nonlinear equations. An experiment using a double ball-bar is implemented to verify the proposed model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1017-1021
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• 1995

Geometric and thermal errors are responsible for major components of the errors of a computer numerically controlled turning center. The planar error of a CNC turning center are comprised of 11 geometric and thermal error components. The error synthesis model is formulated by homogeneous coordinate transformation method and expresses the effect of such error components on the planar error of a CNC turning center. In this paper, the sensitivity analysis of the model on the noises through sensing and the change of temperature is addressed. The sensitivity analysis show that the error systhesis model is robust on the noses and z planar error is much affected by the change of temperatures.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.34-40
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• 2002

Machining accuracy is affected by quasi-static errors of machining center. Since machine errors have a direct influence upon both the surface finish and geometric shape of the finished workpiece, it is very important to measure the machine errors and to compensate these errors. The laser measurement method for identifying geometric errors of machine tool has the disadvantages such as high cost, long calibration time and usage of volumetric error synthesis model. Accordingly, this paper deals with analysis of the geometric errors of a machine tool using ball bar test without using complicated error synthesis model. Statistical analysis method was adopted in this paper for deriving geometric errors using hemispherical helix ball bar test. As a result of experiment, geometric errors of the vertical machining center are compensated by 88%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.501-504
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• 2001

The use of error compensation techniques has been recognized as an effective way in the improvement of the accuracy of a machine tool. The laser measurement method for identifying position errors of machine tool has the disadvantages such as high cost, long calibration time and usage of volumetric error synthesis model. Accordingly, this paper deals with analysis of the position errors of a machine tool using ball bar test without using complicated error synthesis model. Statistical analysis method was adopted in this paper for deriving position errors using hemispherical helix ball bar test.