• 대한기계학회논문집A
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• 제38권8호
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• pp.887-892
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• 2014

일반적인 자기연마가공에서 브러쉬는 연마입자와 자성입자 그리고 약간의 절삭유가 혼합되어 형상을 갖춘다. 그러나 공구가 고속으로 회전하게 되면 대부분의 연마입자는 원심력의 증가로 공구에서부터 떨어져나간다. 이러한 현상은 가공 효율을 저하시키는 결과를 야기한다. 이러한 문제점을 해결할 수 있는 방법 중 하나는 절삭유 대신에 실리콘 겔과 같은 고점성의 물질을 사용하여 입자의 구속을 증가시키는 것이다. 연마입자의 과도한 탈락에 대응하는 또 다른 방법은 습식자기연마(WMAP)이다. 습식자기연마는 절삭유가 공작물의 표면에 충분히 공급된 상태의 자기연마를 의미한다. 본 연구에서는 습식자기연마에서 구속된 연마입자의 구속량과 표면거칠기 향상의 상관관계를 분석하였다. 그 결과 습식자기연마에서 연마입자의 구속률이 낮음에도 불구하고 표면거칠기가 더 많이 향상됨을 알 수 있었다.

• 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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• 제12권5호
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• pp.59-66
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• 2003

This study suggests the new ultraprecision finishing techniques for micro die and mold parts using magnetic field-assisted polishing. Conventional magnetic abrasives have several disadvantages, which are missing of abrasive particle and inequal mixture between magnetic particle and abrasive particle. Therefore, bonded magnetic abrasive particles are fabricated by several method. For example, plasma melting and direct bonding. Carbonyl iron powder is used as magnetic particle there silicon carbide and alumina are abrasive particles. Developed magnetic abrasives are analyzed using SEM. Feasibility of magnetic abrasive and polishing performance of this magnetic abrasive particles also have been investigated. After polishing, surface roughness of workpiece is reduced from 85.4 ㎚ Ra to 9 ㎚ RA.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1832-1835
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• 2003

This paper suggests the selective ultra precision polishing techniques for micro die and mold parts using magnetic-assisted machining. Fabrication of magnetic abrasive particle and their polishing performance are key technology at ultra precision polishing process of micro parts. Conventional magnetic abrasives have disadvantages. which are missing of abrasive particle and inequality between magnetic particle and abrasive particle. So, bonded magnetic abrasive particles are fabricated by several method. For example, plasma melting and direct bonding. Ferrite and carbonyl iron powder are used as magnetic particle where silicon carbide and Al$_2$O$_3$ are abrasive particle. Developed particles are analyzed using measurement device such as SEM. Possibility of magnetic abrasive and polishing performance of this magnetic abrasive particles also have been investigated. After polishing, surface roughness of workpiece is reduced from 2.927 $\mu\textrm{m}$ Rmax to 0.453 $\mu\textrm{m}$ Rmax.

• 한국정밀공학회지
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• 제30권12호
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• pp.1253-1258
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• 2013

Ceramic particles as polishing abrasives are often used in a magnetic abrasive polishing process because they have strong wear resistance. Non-ferromagnetic ceramic abrasives should be mixed with ferromagnetic iron particles for controlling the mixture within a magnetic brush during the polishing process. This study describes the application of the ceramic particles for the magnetic abrasive polishing. The distribution of the magnetic abrasives attached on a tool varies with magnetic flux density and tool rotational speed. From the correlation between abrasive adhesion ratio in the tool and surface roughness produced on a workpiece, practical polishing conditions can be determined. A step-over for polishing a large sized workpiece is able to be selected by a S curve, and an ultrasonic vibration assisted MAP produces a better surface roughness and increases a polishing efficiency.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.151-157
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• 2004

In this paper deals with behavior of the magnetic abrasive using sludge on polishing characteristics in a new internal finishing of seamless stainless steel tube applying magnetic abrasive polishing. The magnetic abrasive using sludge-abrasive grain WA and GC used to resin bond fabricated low temperature. And sludge of magnetic abrasive powder fabricated that sludge was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• 대한기계학회논문집A
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• 제34권10호
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• pp.1499-1505
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• 2010

유연성 공구를 가진 자기연마는 고경도 소재 및 자유곡면 형상 표면의 나노메터급 가공이 가능한 강점을 지닌다. 이러한 자기연마에서 자기연마입자는 시간적, 비용적 측면에서 단순 혼합형 입자가 유리하다. 그러나 단순혼합형 입자는 가공 중 공구로부터 쉽게 이탈하게 되어 가공 시간이 증가 할수록 매우 낮은 가공 효율을 가진다. 따라서 본 연구에서는 단순 혼합형 입자에 오일을 대신하여 실리콘 겔을 매개물로 사용하는 자기연마 입자를 연구하고 그 특성을 분석하였다. 그 결과 자기력 향상과 별개로 입자간 응집력을 높여 입자의 이탈을 줄여 표면거칠기의 향상에 효과가 높음을 확인 하였다. 그리고 실험계획법을 이용하여 고경도 소재인 텅스텐 카바이드의 실리콘 겔 자기연마에서 각 공정변수가 표면거칠기의 향상에 미치는 특성을 평가하고 이를 최적화 하였다.

• 한국정밀공학회지
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• 제21권8호
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• pp.34-42
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• 2004

A new polishing technique for three dimensional micro/meso-scale parts is suggested using a micro quill and a magnetic chain structure. The principle of this method is to polish the target surface with the collected magnetic brushes at a micro tool by the non-uniform magnetic field generated around the tool. In a typical magnetic abrasive finishing process magnetic particles and abrasive particles are unbonded each other. But, to finish the three dimensional small parts bonded magnetic abrasive have to be used. Bonded magnetic abrasives are made from direct bonding, and their polishing characteristics are also examined. Alumina, silicon carbide and diamond micro powders are used as abrasives. Base metal matrix is carbonyl iron powder. It is found that bonded magnetic abrasives are superior to unbonded one by experiment. finally, the polished surface roughness is evaluated by atomic force microscope.

• 한국생산제조학회지
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• 제20권3호
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• pp.274-279
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• 2011

In this study, new abrasives that were composed of iron powder and carbon nanotube (CNT) particle were attempted to be abrasives for magnetic abrasive polishing. Because the CNT particles itself are very small ones with high hardness and magnetic strength, these properties are effective for magnetic abrasive polishing of nonmagnetic materials. As an experimental result for evaluating the machining characteristics in magnetic abrasive polishing, the CNT particles showed better performance than the conventional abrasives such as Fe and CBN powder.

• 한국기계가공학회지
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• 제4권1호
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• pp.7-12
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• 2005

An internal finishing process by the application of magnetic abrasive finishing has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, another method of magnetic abrasive machining in which the N and S magnetic poles are vibrated and a workpiece is rotated only is tried in a non-ferromagnetic pipe(SUS304), and its finishing characteristics is experimently investigated by various effective factors such as vibrating frequency and amplitude. From the experimental results, it is found that the vibration effects of magnetic poles on the finishing characteristics are large in internal finishing.