• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.302-307
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• 2002

In electropolishing, the ion from the surface of the metal is eliminated by means of an electrical potential and current. Electropolishing is being generally known as a replacement for mechanical finishing. In addition to making a surface smoother, it is a more visible means of brightening, deburring, cleaning, stress-relieving and improving the physical characteristics of most metals and alloys. Therefore, the aim of the present study is to investigate the characteristic of electropolishing STS304 and A12024 in terms of current density, polishing time and electrode gap, etc.

• 반도체디스플레이기술학회지
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• 제17권2호
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• pp.61-66
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• 2018

The objective of this research study is to investigate the optimal process parameters of electrical discharge machining (EDM) on SCM440 steel with copper as a tool electrode. The effect of various process parameters on machining performance is investigated in this study. Modern ED machinery is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat treated tool steels, composites, super alloys, ceramics, etc. This paper reports the results of an experimental investigation by Taguchi method carried out to study the effects of machining parameters on material surface roughness in electric discharge machining of SCM440 steel. To predict the optimal condition, the experiments are conducted by using Taguchi's L27 orthogonal array. The work material was ED machined with copper electrodes by varying the pulsed current, pulse on-time, voltage, servo speed and spark speed. Investigations indicate that the surface roughness is strongly depend on pulsed current.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.49-54
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• 2007

Electropolishing, the anodic dissolution process without contact with tools, is a surface treatment method to make a surface planarization using an electrochemical reaction with low current density. Nitinol is a metal alloy composed of Ni and Ti around 50% respectively which has shape memory effect. Nitinol can be put various applications which require purity and high pricision surface of products. The aim of this study is to investigate the characteristic of electropolishing effect for nitinol workpieces. In order to analyze the characteristics of electropolishing effect, surface roughness and micro-burr size were measured in terms of machining conditions such as current density, machining time and electrode gap. The tendencies about improvement of surface roughness and deburring effect by electropolishing for nitinol workpieces were determined.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.47-54
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• 2004

In this study, the electrorheological (ER) fluid was used as finishing agent. Since the apparent viscosity can be controlled by an electric field, the ER fluid can be one of efficient materials in finishing processes. To finish small 3-dimensional structures such as the aspherical surface in optical elements, the possible arrangement of a tool, part and auxiliary electrode was 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 had been 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 was performed considering the non-uniform electric field. Finally, borosilicate glass was finished using the mixture of the ER fluid and abrasive particles and material removal with field strength and surface roughness were investigated.

• 한국정밀공학회지
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• 제22권4호
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• pp.167-172
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• 2005

In this paper. micro electrochemical machining (ECM) for micro structure fabrications is presented. By applying ultra short pulses. the chemical reaction can be restricted only to the region very close to the electrode. Micro ECM is applied to machining micro structures through electrochemical milling process becasuse it doesn't suffer from tool wear. Using this method. 3D micro structures were machined on stainless steel. It was found that micro machining is possible with good surface quality in the low concentration electrolyte,0.1 M H₂SO₄. In ECM, as the machining depth increases, better flushing of electrolyte is required for sufficient ion supply. Layer-by-layer milling is advantageous in flushing. However, layer-by-layer milling causes taper of structures. To reduce the taper, application of a disk-type electrode was introduced. By electrochemical milling, various 3D micro structures including a hemisphere with 60 ㎛ diameter were fabricated.

• 한국정밀공학회지
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• 제19권4호
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• pp.101-108
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• 2002

A specially-built EMM (Electrochemical Micro Machining) / PECM (Pulse Electrochemical Machining) cell, a electrode tool filled with non-conducting material, a electrolyte flow control system and a small & stable gap control unit are developed to achieve accurate dimensions of recesses. Two electrolytes, aqueous sodium nitrate and aqueous sodium chloridc arc applied in this study. The farmer electrolyte has better machine-ability than the latter one because of its appropriate changing to the transpassive state without pits on the surface of workpiece. It is easier to control the machining depth precisely by micrometer with pulse current than direct current. This paper also presents an identification method for the machining depth by in-process analysis of machining current and inter electrode gap size. The inter electrode gap characteristics, inc1uding pulse current, effective volumetric electrochemical equivalent and electrolyte conductivity variations, are analyzed based on the model and experiments.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.59-64
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• 1998

We need to achieve th mass product through methods of higher efficient, higher precise manufacturing process than those of existing precision abrasive machining. Thus, this study is to develop mirror-like surface machining technique of outer diameter of the piston pin by the compound magneto-electrolytic abrasive polishing system. The procedure of machining is followed as first, fulfill the pre-processing by cylindrical grinder, second, complete mirror-like surface by the method of magneto-electrolytic abrasive polishing used CBN non-woven abrasive pads. In this study, it was found that the best suitable conditions of mirror-like surface polishing were that the electrode density was 0.1A/$\textrm{cm}^2$, the applied pressure 1.5kgf/$\textrm{cm}^2$, the feed rate 0.5mm/rev, and the rotoation velocity of workpiece 80rpm, and that the surface roughness was reduced in this conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1844-1847
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• 2003

Electrochemical micro-machining(EMM) is used to achieve a desired workpiece surface by dissolving the metal workpiece with an electrochemical reaction. This machining method can be applied to metal that is difficult to machining using other methods. The workpiece dissolves when it is positioned close to the tool electrode in electrolyte and current is applied. This aim of this work is to develop electrochemical micro-machining(EMM) technique for micro groove shape by establishing appropriate electrochemical parameters of machining

• 한국공작기계학회논문집
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• 제12권2호
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• pp.17-22
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• 2003

Electropolishing is the electrolytic removal of metal in a highly ionic solution by means of an electrical potential and current. It is normally used to remove a very thin layer of material on the surface of a metal part or component. Electropolishing is able to enhance the material properties of a workpiece and to change its physical dimensions. Also, It is suitable for the polishing of both complex shapes and hardened materials, which are difficult to machine mechanically. therefore, the aim of the present study is to investigate the characteristic of Electropolishing A12024 in terms of current density, polishing time and electrode gap, etc.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.29-35
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• 2003

In this research 4 plate type ER-Valves which have same surface but different width and length are designed and an experimental apparatus is constructed. With this experimental apparatus, flow rate and pressure drop of ER fluid flowing in ER-valves are measured with varying electric field strength of ER-valve, and relation between valve types and pressure drop is also experimented. ER fluid is made silicon oil mixed with 40wt% starch having hydrous particles. If we allow the same electric field in the ER-Valve, we came to how that the pressure drop is effected by the electrode length and electrode width. When the strength of the electric field increased, the pressure drop happened big and the flow rate decreased.