• 한국기계가공학회지
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• 제6권4호
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• pp.71-75
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• 2007

Geometrical error of ultra-precision machining due to spherical tool alignment error is analyzed. Deviation of spherical edge, ranged several ten micrometers, generates vertical and horizontal error of tool path and affects profile accuracy of machined surface. Simulation of machined error shows effect of tool alignment error and enables to estimate alignment error. This work provides technical insights into the minimizing of geometrical error of ultra-precision machining.

• 한국기계가공학회지
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• 제6권3호
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• pp.53-57
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• 2007

This paper presents a geometrical error compensation of tool alignment for B axis controlled machine. In precision machining, tool alignment is crucial parameter for machined surface. To decrease tool alignment error, plus tilted tool from B axis center is touched to reference work piece and checked the deviation from original position. Same process is performed in minus tilt. Comparing these 2 touch positions, wheel alignment error in X axis and Z axis can be calculated on B axis center. Experimental results show that this compensation method is efficient to correct tool alignment.

• 한국기계가공학회지
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• 제8권3호
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• pp.1-6
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• 2009

This paper presents a geometrical error compensation of tool alignment for sharp edge bite on B axis controlled machine. In precision micro patterning, bite alignment is crucial parameter for machined surface. To decrease bite alignment error, plus tilted bite from B axis center is touched to reference work piece(pin gauge) and checked the deviation from original position. Same process is repeated for maximum touch deviation value. From this touched position value, wheel alignment error in X axis and Z axis can be calculated on B axis center. Experimental results show that this compensation method is efficient to correct sharp edge bite alignment.

• 한국생산제조학회지
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• 제4권3호
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• pp.39-47
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• 1995

This paper suggests generalize mathematica mode for the benefit of volumetric error analysis of a multi-axis machine tool machining a sculptured surfaces. The volumetric error, in this paper, is defined as a three dimensional error at the cutting point, which is caused by the geometric errors and the kinematic errors of each axis and alignment errors of the cutting tool. The actual cutting position is analyzed based on the form shaping model including a geometric error of the moving carriage, where a form shaping model is derived from the homogeneous transformation matrix. Then the volumetric error is obtained by calculating the position difference between the actual cutting position and the ideal one calculated from a Nonuniform Rational B-Spline named as NURES. The simulation study shows the effectiveness for predicting the behavior of machining error and for the method of error compensation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.627-628
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• 2006

High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of pans created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool alignment errors and surface roughness the scallop generating mechanism in the ball-end milling with tool alignement errors has been studied and simulated. The results indicate that tool alignment errors have no significant effects ell the dimension of scallops in for flat planes.

• 대한정형도수물리치료학회지
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• 제28권1호
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• pp.39-51
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• 2022

Background: The purpose of this study is to investigate the effect of neck and shoulder self-stretching exercise using audiovisual media on neck pain, postural alignment, and joint position error in women with chronic neck pain. Methods: The subjects included 20 women that gave consent to participate in the study voluntarily. They performed the self-stretching exercises using audiovisual media was carried out 20 minutes 5 times a week during 3 weeks. Neck disability index (NDI) and visual analogue scale (VAS) were used to measure the functional disability and pain, A pressure pain threshold was measured using an algometer, and a cervical range of motion (CROM) measurement tool was used to measure the range of motion and error of proprioceptive position sense of the cervical spine. To assess posture alignment, forward head angle (FHA), forward shoulder angle (FSA) were measured using image J software. Results: The neck pain intensity was statistically significantly within group (p<.05). Neck and shoulder functional disability were a statistically significant difference within group (p<.05). Splenius capitis and upper trapezius pressure pain threshold were statistically significant difference in within group (p<.05). The postural alignment was statistically significantly within group (p<.05). The cervical range of motion in neck extension, right and left lateral flexion were statistically significantly within group (p<.05). The joint position error in neck flexion, extension, right and left lateral flexion decreased statistically significantly within group (p<.05). Conclusion: Self-stretching exercise using audiovisual media increased the mobility of the neck, decreased neck pain and joint position error, and improved posture alignment. As a result, there was a positive effect by applying the self-stretching exercise using audiovisual media to people with neck pain. Based on this, it is thought that it can be used as the basis for research related to home training programs for healthy self-management.

• 한국생산제조학회지
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• 제25권2호
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• pp.143-148
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• 2016

A micro end mill is one of the precise tools used in machining ultra-precision products such as microchannel and micropatterned mold. To achieve the required precision of these products, several studies investigated the cutting force, burr formation, and burr generation mechanism of micro end mills; however, there are few studies on the alignment of micro tools, which is the foundation of machining. Hence, in this investigation, relation expressions were derived to determine the relation between the misalignment parameters and the machining accuracy. At the same time, the effect of the machining parameters was analyzed using a multiple linear regression analysis and the analysis of variance. The results indicate that the tilting angle of a micro tool has more influence on the machining accuracy than other parameters.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.387-388
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• 2006

• 한국정밀공학회지
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• 제22권5호
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• pp.80-86
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• 2005

Optical performance evaluation results and an interference fringe pattern analysis of alignment errors for an optical head of a near-field receding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties to assemble the small focusing unit precisely. We composed an evaluation system with an interferometer and evaluated some focusing unit samples aligned and assembled by manual and present the obtained results. Using the conventional optical tool, Code V, a tolerance analysis of the alignment error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the conceptual auto-alignment methodology using a neural network approach is considered.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.803-806
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• 1995

The vibration and nosic of gears is causeed by manufacting error,alignment error in assembly, and thr meshing stiffness of gears which changes periodically as the meshing of teeth process. On a pair of power transmission helical gears with profile error, the relation between the characteristics of gear vibration and the profile error type have been investigated by simulating the vibrational acceleration level and calculating the natural frequency. The results show that the profile error decrease the natural frequency by reducing the tool stiffness and that the concave error type increase the vibrationsl level. And this paper describes the effect of the tip relief on the vibrational acceleration level which a pair of helical gears with concave error generates.