• 한국정밀공학회지
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• 제23권4호
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• pp.146-152
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• 2006

In micro electrochemical machining (ECM), electrodes should be prevented from unfavorable oxide and Passive layer formation on the machined surface or overall corrosion of the entire surface. Generally, metal electrodes corrode, passivate or dissolve in the electrochemical cell according to the electrode potential. Therefore, each electrode must maintain its stable potential. Tn this paper, the stable electrode potentials of tool and workpiece were determined using the potentiodynamic polarization test and verified experimentally considering machining stability and surface quality. Stable workpiece electrode potentials of two different passive materials of 304 stainless steel and nickel were determined in the 0.1 M sulfuric acid. Experimental results show good machined surface and fast machining rate using the determined electrode potentials.

• 한국정밀공학회지
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• 제21권9호
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• pp.196-203
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• 2004

SL(Stereolithography) part is made by piling up thin layers which causes the stair stepping effect at the surface of SL parts. The effect brings about excessive surface roughness and cuts down the merits of using SL part. Hence, additional post-machining finishing such as traditional grinding is required. But the traditional post-machining is detrimental to part geometry and time consuming. In this study, therefore, a paraffin coating and grinding post-machining is newly proposed to improve the surface quality of SL fart. The paraffin which has suitable properties for the proposed post-machining is coated all over the part surface. By grinding the only over-coated paraffin based on boundary of the SL part surface, the surface roughness can be improved without any damage on the part. Also, it is verified that SL part finished by the proposed post-machining process can be applied for rapid tooling as pattern through manufacturing silicon rubber molding and casting test.

• 한국정밀공학회지
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• 제27권8호
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• pp.91-97
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• 2010

Micro-abrasive Jet Machining is one of the new technology which enables micro-scale machining on the surface of high brittle materials. In this technology it is very important to fabricate a mask that prevents excessive abrasives not to machine un-intend surface. Our previous work introduced the micro-stereolithography technology for the mask fabrication. And is good to not only planar material but also for non-planar materials. But the technology requires a 3 dimensional mask CAD model which is perfectly matched with the surface topology of parent material as an input. Therefore there is strong need to develop an automated modeling technology which produce adequate 3D mask CAD model in fast and simple way. This paper introduces a fast and simple mask modeling algorithm which represents geometry of models in voxel. Input of the modeling system is 2D pattern image, 3D CAD model of parent material and machining parameters for Micro-abrasive Jet Machining. And the output is CAD model of 3D mask which reflects machining parameters and geometry of the parent material. Finally the suggested algorithm is implemented as software and verified by some test cases.

• 한국공작기계학회논문집
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• 제17권2호
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• pp.128-134
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• 2008

This paper presents a machining error compensation methodology due to deflection of micro cutting tools in side cutting processes. Generally in order to compensate for tool deflection errors it is necessary to carry out a series of simulations, cutting force prediction, tool deflection estimation and compensation method. These can induce numerous calculations and expensive costs. This study proposes an improved approach which can compensate for machining errors without simulation processes concerning prediction of cutting force and tool deflection. Based on SEM images of test cutting specimens, polynomial relationships between machining errors and corrected tool positions were induced. Taking into account changes of cutting conditions caused by tool position variation, an iterative algorithm was applied in order to determine corrected tool position. Experimental works were carried out to validate the proposed approach. Comparing machining errors of nominal cutting with those of compensated cutting, overall machining errors could be remarkably reduced.

• Design & Manufacturing
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• 제11권2호
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• pp.46-50
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• 2017

EPS used in lost foam casting elastic modulus is extremely low. So it is necessary to derive machining conditions for effective cutting. Therefore this study were analyzed end-milling machining conditions to affecting the surface roughness of EPS foam. The machining conditions were set to depth, feed, and RPM at 3-level. And 18experimental conditions were derived using mixed orthogonal array. The most important condition for surface roughness is RPM. In addition, RPM machining condition range test that can realize surface roughness less than $10{\mu}m$ was performed. he range of RPM conditions is more than 15,000. However the range of RPM conditions is a condition that is difficult to use in actual field. In the future variance analysis and experiments are needed to derive the range of machining conditions available.

• 한국정밀공학회지
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• 제18권12호
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• pp.177-184
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• 2001

C3M(chemical mechanical micro machining) is applied for diminishing the size of burr and fabricating the massless patterning for aluminium wafer(thickness of 1${\mu}m$). It is difficult to perform the micro size machining with the radically increased shear stress. While the miniaturization and function-orientation of parts has been needed in the many field such as electronics, optics and medicine. etc., it is not enough to satisfy the industry needs in the machining technology. In this paper feasibility test of diminishing burr and fabricating maskless pattern was experimented and analyzed. In the experiment oxide layer was farmed on the aluminium with chemical reaction by ${HNO_3}$(10wt%), then the surface was grooved with tungsten carbide tool for the different condition such as the load and fred rate. The result was compared with the conventional machining to show the improvement of C3M with SEM for burr diminish and XPS for atomic existence, AFM for more precise image.

• Design & Manufacturing
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• 제17권2호
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• pp.15-21
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• 2023

In this study, a diamond turning machine and a laser-assisted machining module were utilized for the complex combined cutting of aspheric shapes and fine patterns on the surface of high-hardness brittle material, silicon. The analysis of material's form accuracy and corrective machining was conducted based on key factors such as laser output, rotational speed, feed rate, and cutting depth to achieve form accuracy below 1 ㎛ and surface roughness below 0.1 ㎛. The cutting condition and corrective machining methods were investigated to achieve the desired form accuracy and surface roughness. The rotational speed of the spindle and the linear feed rate of the diamond turning machine were varied in five stages for the cutting condition test. Surface roughness and form accuracy were measured using both a contact surface profilometer and a non-contact surface profilometer. The experimental results revealed a tendency of improved surface roughness with increased rotational speed of the workpiece, and the best surface roughness and form accuracy were observed at a feed rate of 5 mm/min. Furthermore, based on the cutting condition experiments, corrective machining was performed. The experimental results demonstrated an improvement in form accuracy from 0.94 ㎛ to 0.31 ㎛ and a significant reduction in the average value of the surface roughness curve from 0.234 ㎛ to 0.061 ㎛. This research serves as a foundation for future studies focusing on the machinability in relation to laser output parameters.

• 한국융합학회논문지
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• 제9권11호
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• pp.277-284
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• 2018

최근 다축 가공을 통한 정밀가공의 수요가 크게 증대되고 있다. 그러나 5축 이상의 다축 공작기계는 기하학적 관계가 복잡하여 공작기계의 기하학적 정밀도 평가와 분석이 어렵다. 본 연구에서는 먼저, 여러 가지 규정으로 분산되어 있는 KS/ISO 규격을 정리하여 다축 공작기계의 기하학적 정밀도 평가 항목을 체계화하였다. 또한, 다축 공작기계의 정밀도를 평가하고 분석하기 위해 표준공작물을 제안하였고, 표준 공작물을 사전에 정해진 방법과 절차에 따라 가공한 후, 가공면을 3차원 측정하여 분석하였다. 그 결과 표준공작물의 가공 결과와 공작기계의 정밀도가 정성적 및 정량적으로 매우 유사함을 확인하였다. 이 결과로부터 다축 공작기계의 정밀도 분석이 표준공작물의 가공만으로 가능함을 확인할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.26-31
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• 1994

The analysis of acoustic emission signals generated during machining has been proposed as a technique for studying both the fundamentals of the cutting process and process and as a methodology for detecting tool fracture on line. In this study, AE signals detected during End Milling were applied as the experimental test to sensing tool fracture on the CNC vertical milling machine. Because automatic monitoring of the cutting condition is one of the most important technologies in machining, the in-process detection of cutting tool life including fracture has been investigated by performing experimental test.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.127-128
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• 2009