• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.32-38
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• 2006

The magnetic fluid polishing technique can polish the tool of complex shape, because the polishing method which polishes as compress the workpiece by the magnetism abrasives to arrange to the linear according to the line of magnetic force. Therefore, we producted the magnetic fluid polishing device in order that mirror like finishing processes the tool surface. In order to a polishing condition selection, polishing characteristic was estimated by polishing conditions which are magnetic flux density, polishing speed, grain size, magnetic fluid. The tool was polished to the selected polishing condition. The result to evaluate the polished tool's performance with the cutting force and tool wear, the polished tool's performance was improved compared with the tool not to polish.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.354-361
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• 2005

In high speed cutting process, due to the friction between the tool and workpiece, a temperature rise of contacting part is serious. It need to develop cutting tool for overcoming such a poor condition. So now, some studies, the optimization of tool shapes, the fine grains of tool material, multi-layer coating of tools are processing. If mirror finishing on the tool is processed, there is advantage of relation between chip and tool, because of less friction, and also tool's lift would be increased. As a result mirror like finishing is expected efficient enhancement of tool. Generally, it is too difficult to process by a general way for tools of complex shapes, it is required a new method to process such complex shape tools. The magnetic fluid polishing technique can polish the workpiece of complex shape, because the polishing method which polishes as compress the workpiece by the magnetism abrasives to arrange to the linear according to the line of magnetic force. In this paper, We polished the surface of the high speed cutting tool using the magnetic fluid polishing technique, to enhance the performance of the high speed cutting tool.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.81-86
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• 2006

The machining parts must be produced within the specification of drawing and those will be able to meet function and efficiency. At that time, it is very important not only precision machine and machining technique but also the measurement technique. So, the improvement of measurement technique is to be joined together at once with improvement of machining technique. Finally, the quality and value of the parts are decided by precision measurement. This paper aims to study on the machined surfaces characteristics of aluminum alloy by AFM(Atomic force microscope) measurement. The objective is contribution to ultra-precision machining by exhibit foundation data of surface roughness and tool wear when parts are cutting with diamond tool at the factory.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.4
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• pp.67-77
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• 1995

In modern industry the requirement of automation of manufacturing process increases so that unmanned system has been popular as an ultimate goal of modern manufacturing process. In unmanned manufacturing process the tool fracture is a very serious problem because it results in the damage of workpieces and can stop the operation of whole manufa- turing system. In this study, image processing technique is used to detect the fracture of insert tip of face milling using multi-point-tool. In order to acquire the image information of fracture shape of rotation insert tip. We set up the optical system using a light beam chopper. In this system we can reduce the image degradation generated from stopped image of rotating insert tip using image restoration technique. We calculated the mean square error to diagnose the condition of tool fracture, and determind the criteria of tool fracture using experimental and staticstical method. From the results of this study we've developed non- contact detection technique of tool fracture using image processing method and proposed the fracture direction of automation and unmanned system considering the optimal time of tool change milling.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1783-1793
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• 1993

Pattern recognition technique using fuzzy c-means algorithm and multilayer perceptron was applied to classify tool wear states in turning. The tool wear states were categorized into the three regions 'Initial', 'Normal', 'Severe' wear. The root mean square(RMS) value of acoustic emission(AE) and current signal was used for the classification of tool wear states. The simulation results showed that a fuzzy c-means algorithm was better than the conventional pattern recognition techniques for classifying ambiguous informations. And normalized RMS signal can provide good results for classifying tool wear. In addition, a fuzzy c-means algorithm(success rate for tool wear classification : 87%) is more efficient than the multilayer perceptron(success rate for tool wear classification : 70%).

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.2
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• pp.1-10
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• 2017

Purpose : This study was aimed at investgating the effect of short foot exercise(SFE) using an imagery technique on chronic ankle instability(CAI). Methods : Twenty subjects with chronic ankle instability were selected by using the Cumberland ankle instability tool. They were randomly assigned to one of two groups(10 in each group) : namely the short foot exercise group and imagery technique group. The short foot exercise group performed short foot exercise for 6 weeks(3 times a week, 15 min per session). The imagery technique group performed short foot exercise(3 times a week, 15 min per session) and the imagery technique(3 times a week, 5 min per session) for 6 weeks. We measured chronic ankle instability, balance and threshold of vibration sensation before and after exercise by using the Cumberland ankle instability tool, Biodex Balance System and VSA-II, respectively. Results : We found statistically significant differences in cumberland ankle instability tool, balance and threshold of vibration sensation between the groups(p<.05). Conclusion : We confirmed the effect of short foot exercise using an imagery technique. Thus, we thought these results could be used as basic data and reference for musculoskeletal therapy or intervention using an imagery technique.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.223-229
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• 2003

Tool wear monitoring is an important technique in the flexible manufacturing system. This paper studies the end mill wear detection using CCD camera and pattern recognition method. When the end mill working in the machining center, the bottom edge of the end mill geometry change, this information is used. The CCD camera grab the new and worn tool geometry and the area of the tool geometry was compared. In this result, when the values of the subtract worn tool from new tool end in 200 pixels, it decides the tool life. This paper proposed the new method of the end mill wear detection.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.319-320
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• 2002

Numerical simulation of chip formation during high speed machining requires knowing the friction at tool/chip interface. This parameter is hardly identified and generally the loadings (temperature, force) during the identification are not similar to those encountered during machining. Thus, Coulomb friction identified with pin-on-disc device is often used to conduct numerical simulation. The used of this technique cannot leads to good numerical results of chip formation compared to the experimental tests especially in the case of low uncut chip thickness. In this contribution, we propose a new method to evaluate the friction at tool/chip interface. In fact several Coulomb friction parameters are identified corresponding to several parts of the cutting tool. Experimental tests have been conducted allowed us to determinate both the level and the distribution of the Coulomb friction. Experimental results are also compared to the results of orthogonal cutting simulation. We show that this technique allows predicting accuracy results of chip formation.

• Journal of the Korean Society for Precision Engineering
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• v.2 no.1
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• pp.62-71
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• 1985

This is a study on the monitoring technique in tool failure and tool life by AE method. The relation between amplitude level of AE signal and flank wear width was studied by experiments. The relation between amplitude level of AE signal and tool life was also studied. As the result, it was observed that amplitude level of AE signal was only affected by cutting velocity. Amplitude level of AE signal was directly proportional to flank wear width and the increasing rate was related to cutting velocity. So, the relation between amplitude level of AE signal and tool life was represented as follow: $CT^n$ = $AE_{rms}$ where, n=0.35 C=9.5*$10^{-2}$

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.450-455
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• 2002

Quality of endmill applied to high speed Machining can be classified in precision and tool life. Especially, Endmills are damaged easily when high speed machining are occurred vibration and deflection by thin and long shape of endmill, limitation of chip-pocket. Furthermore, Endmills are determined tool life by the quality of base material and the character of coating. This study have carried on research and analysis about grinding technique, circumference technique to improve precision that determine the quality of endmill. As the result of this study, that the technique is able to manufacture endmill applied to high speed Machining have been obtained.