• 한국기계가공학회지
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• 제5권1호
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• pp.13-18
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• 2006

The magnetic abrasive machining has been developed as a new finishing technology to obtain a fine surface of workpiece. In this paper, a static magnetic field method and a magnetic abrasive brush which has many technical advantages, are applied for the magnetic abrasive machining. In the experiment, some items such as finishing time, ratio of the magnetic abrasives to Fe-powder, motor revolutions per minute, and motor ratio revolutions per minute are tested. The results of this study have shown the fact that the burr height is mostly affected by the finishing time and the abrasive ratio. Also, it has been found that the magnetic abrasive machining is a possible new technology for the deburring.

• 한국공작기계학회논문집
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• 제13권3호
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• pp.61-67
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• 2004

In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. In this study, magnetic field-assisted polishing technique is applied to remove the burr which exists in nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals was investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1255-1261
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• 2004

A variational approximation procedure is introduced to study the contact stresses between a representative asperity and a feature generally happening in superfinishing processes such as FAM. After a description of the model under consideration is presented, a system of governing equation for the model is derived fullowed by the assumptions made in order to make progress in model development. Final computation is made to evaluate contact stresses on an elastic asperity tip in small scale in size and a computer simulation is performed for detailed surface profile variations on a representative feature. Numerical results are presented along with a discussion of the conclusions that can be drawn from this analysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.59-60
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• 2006

The slurry stability and removal rate during recycling of slurry in silicon wafer polishing was studied. Average abrasive size of slurry was not changed with recycling time, however, large particles appeared as recycling time increased. Large particles were related foreign substances from pad or abraded silicon flakes during polishing. The removal rate as well as pH of slurry was decreased as recycling time increased. It suggests that the consumption of OH ions during recycling is the main cause of decrease of removal rate. Therefore, it is important to control pH of slurry to obtain optimum removal rate during polishing.

• 한국정밀공학회지
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• 제19권12호
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• pp.134-141
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• 2002

The ER fluid can be one of efficient materials in ultraprecision polishing for optics, ceramics and semiconductors because of electrically controllable apparent viscosity. To finish small 3 dimensional structures such as the aspherical surface in optical elements, the possible arrangement of a tool, workpiece and auxiliary electrode is described. We examined the influence of the addition of a few abrasive particles on the performance of the ER fluid by measuring yield stress, and observed the behavior of abrasive particles in the ER fluid by a CCD camera, which is also theoretically predicted from the electromechanical principles of particles. On the basis of the above results, the steady flow analysis around the rotating micro tool is worked out considering the non-uniform electric field. Finally, Pyrex glass is polished using the mixture of the ER fluid and abrasive particles, and the effect of the electric field strength is evaluated.

• 한국전기전자재료학회논문지
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• 제25권7호
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• pp.569-573
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• 2012

We investigated the speed change of the diamond spherical abrasive during the substrate surface polishing under the pad compression by using classical molecular dynamics modeling. We performed three-dimensional molecular dynamics simulations using the Morse potential functions for the copper substrate and the Tersoff potential function for the diamond abrasive. As the compressive pressure increased, the indented depth of the diamond abrasive increased and then, the speed of the diamond abrasive along the direction of the pad moving was decreased. Molecular simulation result such as the abrasive speed decreasing due to the pad pressure increasing gave important information for the chemical mechanical polishing including the mechanical removal rate with both the pad speed and the pad compressive pressure.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2786-2795
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• 2000

Recently, the technology for internal polishing is needed for ultra-clean machining for the prevention of corrosion and pollution of parts is the area of high technology industries such as semiconductor, electronics, telecommunication optics, aerospace, and motors. In this study, an internal polishing system using the magnetic force was developed for the production of ultra-clean tubes with averaged surface roughness ranging from 0.2㎛ to 0.05㎛ or less, and magnetic abrasives composed of WC/Co powder were developed, After finding the optimal condition on each, machining characteristics using newly developed abrasive were analyzed. Form the results obtained by experimental design method, the optimal polishing condition was analyzed and, thhereafter internal polishing was done.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1836-1839
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• 2003

This paper describes the surface polishing characteristics of a flat and free surface ferromagnetic substance(SM45C) that magnetic abrasive polishing processed. The effects of the various working factors on the surface roughness are clarified by experiments respectively, such as magnetic flux density. rotation speed of magnetic head. working gap, feed rate of workpiece. diameter of magnetic abrasives. and shape of workpiece. On the basis of these experiments, the polishing mechanism is discussed and the characteristics of the polishing process are described. In addition, it is found experimentally that die ＆ mold surfaces are also polished precisely by this process

• 한국기계가공학회지
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• 제15권2호
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• pp.9-15
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• 2016

The dynamics of gas-particle flow from a supersonic abrasive blasting nozzle have been studied by 1-D analytical calculation, including wall friction effects inside the nozzle. The developed code in the present study shows a satisfactory agreement with the other study's results. By utilizing the code, the redesign and optimization of the inner contour of a commercial abrasive blasting nozzle were carried out, and it was found that the redesigned nozzle in the present study can produce faster particle velocities at the nozzle exit by up to 22% compared with the original commercial nozzle.

• 한국공작기계학회논문집
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• 제18권1호
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• pp.22-28
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• 2009

In order to optimize the polishing process, Run to Run control scheme has been applied to the micro mold polishing in this study. Also, to fully understand the effect of parameters on the surface roughness a design of experiment is performed. By linear approximation of main factors such as gap and rotational speed of micro quill, EWMA (Exponential Weighted Moving Average) gradual mode controller is adopted as a optimizing tool. Consequently, the process converged quickly at a target value of surface roughness Ra 10nm and Rmax 50nm, and was hardly affected by unwanted process noises like initial surface quality and wear of magnetic abrasives.