• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.204-205
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• 2004

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.29-37
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• 2002

The wavelet transform is a popular tool for studying intermittent and localized phenomena in signals. In this study the wavelet transform of cutting force signals was conducted for the diagnosis of grinding conditions in grinding process. We used the Daubechies wavelet analyzing function to detect a sudden change in cutting signal level. STD11 workpiece was 85 times of machined pieces cut by the WA wheel and a tool dynamometer obtained cutting force signals. From the results of the wavelet transform, the obtained signals were divided into approximation terms and detailed terms. At dressing time, the approximation signals were slowly increased and 45 machined times noticed dressing time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.19-27
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• 2011

A weaving machine for texture industry uses a lot of needles and the nib of these needles is necessary to be kept with sharp edge. The re-grinding of the needle by a special purpose of the grinding wheel can be selected for achieving this aim. This study focused on the manufacture and performance assessment the special grinding wheel. A forming mold for the grinding wheel was designed and a sintering process for furnace process control was established. Manufactured wheels were tested for determining suitable grade of the wheel. The selection of optimal grinding conditions was achieved by a response surface method and a genetic algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.381-386
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• 2004

A flexible disk grinding system process has been introduced that utilized varying disk orientation with respect to workpiece along with the applied feed speed. A known process model methodologies has been used to fomulate processed surface profiles. Various process conditions including cutting speed, maximum feed speed and orientation angles could applied to observe process outcomes. Even though continuous and constant feed speed has been applied to the process, the results from the trapezoidal input velocity profiles would be observed and compared. Based on the control strategies including neural network methodologies, several output results were compared to find the optimum process condition.

• Journal of Power System Engineering
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• v.4 no.2
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• pp.25-30
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• 2000

The grinding process is very complex and relates many parameters to control the process. As this reason, a theoretical analysis and a quantitative estimation of the grinding process has not been well established. In this study, the in-process monitoring system was suggested by applying the neural network for monitoring and shooting the malfunction of cylindrical plunge grinding process. This system used the power signals from the electric power meter. This neural network was composed of processing elements [4-(5-5)-3] with 4 identified power parameters. Because sensitivity is blunted some minute vibration components, the simulation result of this system has appeared about 10% erroneous recognition in the uncertain pattern and the average success rate of the trouble recognition was about 90%. Consequently, the developed system, which applied to the power signals, can be recognize enough to monitor the grinding process as in-process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.309-314
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• 2004

A flexible disk grinding system process has been introduced that utilized varying disk orientation with respect to workpiece along with the applied feed speed. Various process conditions including cutting speed, maximum feed speed and orientation angles could applied to observe process outcomes. Even though continuous and constant feed speed has been applied to the process, the results from the trapezoidal input velocity profiles would be observed and compared. Based on the control strategies including neural network methodologies, several output results were compared to find the optimum process condition. Two axis control results were displayed showing better performance with higher trajectory error for larger training epoch.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.374-378
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• 2003

From linear motor feed system model, two axis control rules have been applied. As an application process, a flexible disk grinding system process has been also introduced that utilized varying disk orientation with respect to workpiece along with the applied feed speed. A known process model methodologies has been used to fomulate processed surface profiles. Various process conditions including cutting speed, maximum feed speed and orientation angles could applied to observe process results sensitivities. Even though continuous and constant feed speed has been applied to the process, the results from the trapezoidal input velocity profiles would be observed and compared.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.1
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• pp.9-13
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• 1993

Micro-electronics를 핵으로 하는 기술혁신의 물결이 눈부시고, 우리 주변의 일상생활이 하루가 다르게 변해 가고 있다. Leading-edge technology, high technology, advanced technology 등으로 호칭되는 일군의 새로운 기술의 절대적 level이 현재 어디에 위치해 있는지 확인 조차 하기 어렵고 첨단기술 제품의 성능에 넋을 잃을 지경이 지만 고려청자나 이조백자에 대해서는 현재의 기술을 가지고도 그 재현이 곤란하다. 이와 같이 시차의 이중성 속에서 제품의 부가가치를 높이고 생산성을 올리기 위해서는 가공기술의 고도화를 가하지 않으면 안된다. 어떤 소재를 설계된 모양대로 변화시키는 일련의 과정을 가공이라 한다면 이에는 변형가공(주조, 소성가공), 부가가공(용접), 제거가공(절삭, 연삭)등을 생각할 수 있으며 이들 사이의 가공정도의 개략치는 다음과 같다. (그림.1 가공공정에 따른 가공정도) 공작물에 요구되는 가공정도는 시대의 변천과 더불어 level up되고 이를 위한 기술 개발이 부단히 이어오고 있다. 1960-70 년대의 생산가공 기술은 .mu. m 단위인 $10^{-5}$--$10^{-6}$m의 범위의 가공정도를 생산 line으로 실현하는 것이 중점 개발 목표였다. 그러나, 현재는 $10^{-5}$--$10^{-7}$m를 목표로 한 submicron 가공정도 실용기에 들어서고 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.61-67
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• 2017

Research into the selection of suitable materials and the development of fast processing methods for press die manufacturing is absolutely necessary to reduce the production time and cost. In particular, knowledge of its heat properties must be considered whendeveloping a long press die. Generally, as the main component materials of press dies, Cr, W low alloy tool steel, high carbon-high chrome steel, high speed steel, etc., are used as thetooling steel for the cold die. Machine tools and wire-cut electric discharge machining are mainly used for processing the press die parts. There are many differences in the machining time and life cycle of die parts depending on the machining process. The parts produced by milling and grinding have a high manufacturing time and cost with a long life cycle, while thosemade by milling and wire-cut discharge machining have areduced manufacturing time and cost,whereastheir die life cycle is reduced. Therefore, in this study, we will discuss amethod of improving the life cycle of the die parts by using heat treatment as a processing method that reduces the manufacturing time and cost. SEM, EDS analysis and the surface roughness analysis of the surface and center of the workpiece are used for analyzing the specimens produced by three machining methods, viz. milling - grinding, milling - wire cut discharge, and milling - wire cut discharge - heat treatment. A method of making die parts having the same life cycle as those produced by milling - grinding is developed with the milling - wire cut discharge - high temperature tempering method.

• Proceedings of the Optical Society of Korea Conference
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• 1997.08a
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• pp.85-85
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• 1997

Czochralski 방법에 의해 육성된 Nd:YAG 단결정으로부터 CW mode의 1064nm laser를 발진시켰다. 육성된 단결정은 직경 50mm, 길이 120mm 이었으며, Nd 이온 농도는 O.2~0.9at% 이었다. 육성된 단결정 boule로 부터 결정학적 결함부위인 core 및 facet가 없는 양질의 단결정 부위를 Twyman-Green interferometer로 선빌하였다. 추출핀 부위는 절단, 가공, 연마공정 및 코팅 공정을 통해 직경 6.35mm, 길이 lOOmm의 laser rod를 제작하였다. 절단은 core drill, 또는 원통 연삭기를 사용하여 rod 형태로 가공하였으며, 상$\cdot$하면 polishing은 평행도 10", 직각도 5', 평활도 $\lambda$/10 수준까지 실험실에서 자체 가공하여 일반적인 laser 발진용 rod의 spec.을 만족시킬 수 있었다.