• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.45-52
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• 1996

It is one of the important causes that the precision of the thread grinder decide the machining errors of the ball screw. The approach described in this study demonstrates how the dominant causes of the inaccuracies in thread grinding system can be determined. To evaluate the machining error of thread grinder, rotary encoder is allocated to spindle shaft and master screw for measuring the rotational transfer error between spindle shaft and master screw and the laser measuring system is used for checking the movement error.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.22-28
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.15-19
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• 2003

• Journal of the Korean Society of Safety
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• v.11 no.2
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• pp.136-142
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• 1996

In this paper the safety problems of bench grinder have been reported. The safety status of bench grinders in 169 companies in Kyungbuk province was investigated. It was found that the two most important safety problems are the improper installations of workrests and the use of side (instead of front) of the grinding wheels.

• Journal of Trauma and Injury
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• v.36 no.1
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• pp.32-38
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• 2023

Purpose: This study aimed to identify the characteristics of patients injured by high-rotation cutting tools and the factors related to the severity of their injuries. Methods: Adult patients (≥18 years), who presented to the emergency department (ED) after a high-rotation cutting tool injury and who were registered in the Korean Emergency Department-based Injury In-Depth Surveillance (2011-2018) database, were included. Patients' demographic characteristics, injury-related factors, and Injury Severity Scores were collected. All included cases were categorized into two groups according to the tool that caused the injury: grinder versus nongrinder. The characteristics of the two groups were compared, and the factors associated with the severity of injuries were investigated. Results: Among 8,697 ED visits, 4,603 patients had been using a grinder and 4,094 had been using a nongrinder tool. The most frequently injured body part while using a grinder was the hand (46.4%), followed by the head (23.0%). While using a nongrinder tool, the most frequently injured body part was also the hand (64.0%), followed by the lower leg (11.4%). The odds of a severe injury were affected by patient age (odds ratio [OR], 1.024; 95% confidence interval [CI], 1.020-1.028) and using a grinder (OR, 2.073; 95% CI, 1.877-2.290). The odds of a severe injury using a grinder were higher in arm injuries (OR, 1.60; 95% CI, 1.40-1.83) and multiple-part injuries (OR, 1.998; 95% CI, 1.639-2.437). The odds of a severe injury using a grinder were lower for head injuries (OR, 0.481; 95% CI, 0.297-0.781). Conclusions: Injuries from grinders were more likely to affect the head and neck than nongrinder injuries, despite the lower severity. The current lack of regulations on grinders in occupational safety and health standards warrants relevant legislation and the development of applicable safety equipment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.65-69
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• 2002

In order to practicalize high precision centerless grinder for machining the ferrule, its feeding system is designed and tested. For satisfying the desired diametric tolerance and cylindricity of the ferrule, the feeding system is designed to have relatively high axial stiffness of 600 N/$\mu\textrm{m}$, high angular motion accuracy of 0.5 arcsec/mm in yaw direction and minimum resolution of 0.05 $\mu\textrm{m}$. A prototype of feeding system is built up with hydrostatic guideway and ballscrew. A linear scale with 0.05 $\mu\textrm{m}$ of resolution is used for position feedback. Experimental results show that the feeding system has the infinity of axial stiffness within the range of 1000 N and 0.3 arcsec/mm of yawing error. Also the feeding system shows obvious step response against 0.05 $\mu\textrm{m}$/step command without the lost motion or backlash. Although the vertical stiffness is reduced to 440 N/$\mu\textrm{m}$ by the elastic deformation of rail, it is good enough to use for machining the ferrule. From above, it is confirmed that the feeding system is applicable to centerless grinder for machining the ferrule.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1525-1530
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• 2014

In this research, we describe teaching based sweeping control for grinder robot has been proposed as a system which is suitable to work utilizing pressure sensitive alternative to human. Teaching method is used for grinder robots operations because of their position accuracy, path accuracy, and machining reaction force. A grinder robot for two-dimensional iron plate was developed on the basis of an force sensor based teaching method. An automatic-path-generation method and experimental results using specific points was adopted to reduce the number of teaching points and time. And also, in order to determine the proper machining conditions, various machining conditions such as grinder-wheel rotation speed and robot moving speed, were evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4732-4737
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• 2011

A standing grinder with a vacuum dust collection, which works grinding a surface and collecting dust occurred simultaneously, is needed to clean the surface before painting, or to remove a weld bead burr in the industrial field. In recent it trends to be compact and potable with high grinding and dust collection power, and low noise. As increasing these grinding and dust collection power, the noise and weight of standing grinder occurs an important problem. To solve these problem, an efficient cyclone separator was designed and developed by Ansys-CFX analysis and experiments. A weight of the developed grinder part was 5.9kg, which can be easily handled on standing by workers. and a noise level of the developed prototype was measured 69.9 dB(A).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.86-91
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• 2002

The regression analysis in the six sigma process is used to reduce the vibration of an electric grinder. The vibration characteristics and the contribution of each part to overall vibration of the electric grinder is investigated through various vibration measurements and frequency analysis for the assembled and disassembled one. Then the application of the regression analysis finds out that the rotating components of the armature have more severe contributions to the overall vibration than the frequency components of the fan or the gear part, which is decided with higher value of the coefficient of determination. The unbalance and looseness of the armature and the fan are tested again by the regression analysis in order to decide how much unbalance or looseness should be reduced for the predetermined goal of vibration level of the electric grinder. These results show that the regression analysis can be a valuable tool in production line to decide where and how much faults needs to be adjusted for the reduction of vibration and noise.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.131-144
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• 1995

This paper presetns modifications of a hydraulic shovel to robotize, and we derive a dynamic model of the hydraulic shovel arms,and hydraulic analysis are discussed . Then , our purpose is making to imitate a target railroad line of the grinder position by the PID control. Moreover, to determine the gains of the PId controller, we referenced the Ziegler and Nichols' method. In this paper, we demonstrated that the PID control is available for system. These results indicated the possibility of practical use fo the deburring robot with the hydraulic shovel.