• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.119-124
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• 1996

End milling operation is very important in machining precision components. Deterioration of surface roughness and surface geometry will cause more process for surface finishing. According to the feed rate and the cutting edge geometry, the cusp which is geometrically uncut surface is determined. To reduce the cost for dinishing operation after end milling, the cusp must be remaianed in small size as possible. Due to the cylindrical type of the end mill, tool deflection is one of the main problems in surface generation. The cutting resistance and the rigidity of the end mill will determine the size of tool deflection. One more important factor which deteriorate surface quality comes from the error in manufacturing end mills. Run-out of end mill which is the difference of the radius of each cutting edges will produce the difference of the cusp size in every rotation of end mill. These three major factors to the surface quality will be analized and the result will be compared with experimental ressult.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.329-342
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• 1994

In order to reduce the production cost and improve the quality of dairy feed, several dairy feed mill models suitable for Korean farm size were developed. 6 TMR models were developed for the 1000, 600, 200 head of dairy cattle, and evaluated for capital investments and production costs to suggest the best model. Followings are summary of this study : 1. TMR terminal models were designed that dairy production capacity of TMR1000 models are 40 ton/day, TMR600 model is 20 ton/day and TMR200 models are 10 ton/day. Also, they can be extended their capacity up to twice. 2. Capital investment of TMR terminal models is 145 million won for TMR200-1,205 million won for TMR600 and 609 million won for TMR1000-3 model. 3. The bigger TMR terminal model has the more advantage in production cost. The best model for 1000 head of dairy cattle farm was TMR1000-3 with 10,849 won/ton of production cost, TMR600 for 600 head of dairy cattle farm with 13,829 won/ton, TMR200-1 for 200 head of dairy cattle farm with 16,943 won/ton of production cost, so feed production cost for the 200 head farm was 50% higher than 1,000 head size farm.

• Journal of Biosystems Engineering
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• v.19 no.4
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• pp.343-357
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• 1994

Current commercial dairy feed has various problems in low feed productivity, inadequate formulation and higher feeding cost due to excessive capital investment and non-specialized system for the end product. To solve those problems, 6 TMR terminal models were developed in this study. The developed TMR terminal system consists of TMR terminal, TMR main center and combined system linked TMR terminal and TMR main center. 15 TMR main center models were developed to support 10, 20, 30, 40, 50 TMR terminal(30 ton/day basis) by 3 different types, and evaluated for capital investment and operation cost by the analysis of the newly developed computer program. Optimum model size is analyzed and suggested for each model. Followings are summary of this study : 1. The capital investment costs of TMR main centers were 1,600 to 3,800 million won for type 1, 2,200 to 4,500 million won for type 2 and 2,200 to 4,800 million won for type 3. Also model MACE30 or bigger were justified as the economical models. 2. The feed production costs of TMR main center models were 3,166 to 4,824 won/ton for type 1, 3,816 to 6,182 won/ton for type 2 and 3,990 to 6,263 won/ton for type 3. So feed production cost range was 3,166 to 6,263 won/ton. 3. The bigger production capacity, the less TMR main center production cost. The feed production cost of the biggest model MACE50 was 62~65% of smallest model MACE10.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.273-279
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• 2017

In sheet metal forming numerical analysis, the strain hardening equation has a significant effect on calculation results, especially in the field of spring-back. This study introduces the Kim-Tuan strain hardening model. This model represents sheet material behavior over the entire strain hardening range. The proposed model is compared to other well known strain hardening models using a series of uniaxial tensile tests. These tests are performed to determine the stress-strain relationship for Al6016-T4, DP980, and CP Ti sheets. In addition, the Kim-Tuan model is used to integrate the CP Ti sheet strain hardening equation in ABAQUS analysis to predict spring-back amount in a bending test. These tests highlight the improved accuracy of the proposed equation in the numerical field. Bending tests to evaluate prediction accuracy are also performed and compared with numerical analysis results.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.27-37
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• 2005

Direct writing technology on the silicon wafer surface is used to reduce the size of the chip as the miniature trend in electronic circuit. In order to improve the productivity and efficiency, the real time quality estimation is very important in each semiconductor process. In laser marking, marking quality is determined by readability which is dependant on the contrast of surface, the line width, and the melting depth. Many researchers have tried to find theoretical and numerical estimation models fur groove geometry. However, these models are limited to be applied to the real system. In this study, the estimation system for the line width during the laser marking was proposed by process monitoring method. The light intensity emitted by plasma which is produced when irradiating the laser to the silicon wafer was measured using the optical sensor. Because the laser marking is too fast to measure with external sensor, we build up the coaxial monitoring system. Analysis for the correlation between the acquired signals and the line width according to the change of laser power was carried out. Also, we developed the models enabling the estimation of line width of the laser marking through the statistical regression models and may see that their estimating performances were excellent.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.361-361
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• 2012

사파이어 단결정은 LED 소자의 기판으로 널리 사용되고 있으며 현재 소자 수율을 향상시키기 위하여 6인치 이상의 대구경 웨이퍼를 만들기 위한 많은 노력을 경주하고 있다. 단결정, 특히 반도체 단결정 웨이퍼에서 ($00{\cdot}1$), ($10{\cdot}2$) 등의 어떠한 결정학적인 방위(crystallographic orientation)가 표면과 이루는 각도, 즉 표면방위각(off-cut 또는 misorientation angle)의 크기와 방향은 제조된 LED 소자의 물성에 영향을 끼치므로 웨이퍼를 가공할 때 정확하게 콘트롤해야 한다. 본 연구에서는 고분해능 X-선을 이용하여 표면이결정학적 방향과 이루는 면방위각을 정밀하게 결정하는 측정법을 연구하였다. 기존의 ASTM 의 측정법과는 다른 원리를 이용하고 웨이퍼의 휨(bending)이나 측정고니오 회전축의 편심과 무관하게 표면방위각을 결정하는 새로운 이론적 모델을 제시하고 그 모델을 적용하여 표면의 수직축이 대구경 사파이어 ($00{\cdot}1$) 축과 이루는 표면방위각을 정확하게 측정 분석하였다. 본 연구에서 사용한 6인치 사파이어 웨이퍼에 대하여 표면방위각은 $0.21^{\circ}$이었으며 표면각이 나타나는 방향은 웨이퍼의 primary edge 방향으로부터 $-1.2^{\circ}$ 벗어나 있는 방향이었다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.2
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• pp.223-231
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• 1986

During the past decade, the Quick Tool-Life Testing Method has been studied. However, a generalized theory and testing method for the quantitative measurement of tool wear have not been developed yet. Among many factors to affect the tool wear, the flank wear is regarded as a main factor. In this study, the behavior of the flank wear for carbide tool was studied as a preceding step to present a simple method for Quick Tool-Life Testing, and it was found that the flank wear varies in direct proportion to cutting time, and the following general equation is obtained for the flank wear curves with respect to cutting time and velociety.

• Elastomers and Composites
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• v.44 no.4
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• pp.378-383
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• 2009

In this study, the use of a condensed model is proposed for the simulation of forming of sandwich sheet with pyramid core. A corresponding finite element analysis for L-type bending is carried out to prove the accuracy and the effectiveness. In order to improve the accuracy of forming analysis, more precise modeling of core shape and consideration of work-hardening of previous core forming are carried out. Simulation results are compared with those of experiment. Deformation shape and post-buckling behavior by simulation are in good agreement with those of experiment for the considerable range of deformation. From the comparison of force-displacement curve, it is shown that the proposed model shows good prediction of post-buckling behavior.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.166-175
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• 1996

In recent years, air-conditioning units designed with higher efficiency and more compactness are required due to emphasis on energy efficiency in home electrical appliances. This trend in the air-conditioning industries has accelerated the development of improved heat exchanger with a better performance in heat transfer aspects. In this study, experiments were performed to investigate the shape and configuration of fins affecting on the performance of the conventional fin-and-tube type heat exchanger equipped in a commercial air conditioners. The geometry similtude method was employed to measure the heat transfer coefficient and pressure drop. Experimental results show that this method is very useful to analyze the heat transfer characteristics of the fin-and-tube type heat exchanger. It is also found that the slit fin has better performance than the conventional fin type in the air conditioners. The present results indicate that heat transfer from the fin si influenced by the parameters such as the forming area of the slit fin, the type of interrupted surfaces like a louver or slit, slit patterns and slit raised direction, and it also affects the overall heat exchanger performance.

• JOURNAL OF ELECTRICAL WORLD
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• s.264
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• pp.70-78
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• 1998

석유 등의 화석연료가 연소되면서 발생하는 이산화탄소를 주체로 하는 ''온실효과가스''의 배출량이 점점 더 증가해 감에 따라 지구온난화가 국제적으로도 커다란 환경문제가 되고 있다. 이산화탄소의 배출을 억제하기 위한 구체적인 시책은 바로 자에너지(에너지 절약/ 이용합리화)의 수행이다. 이번에 자에너지를 주목적으로, ISO14001의 환경매니지먼트 모델을 전체적으로 지원하는 공장에너지관리시스템과 조명$\cdot$빌딩분야에서 환경매니지먼트 모델을 지원하는 조명제어시스템 및 빌딩 설비 감시시스템을 구축하였다. 신규개발한 Controller의 소프트웨어는 24시간 가동가능한 OS(Operating System)에 제어미들웨어를 탑재하여 Object설계방법으로 제작된 기능별 어플리케이션 소프트웨어를 각 시스템별로 조합한다. 하드웨어는 퍼스컴과 동일한 DOS/V머신 구성으로 하여 시스템의 주체가 되는 부송부의 하드웨어를 개발하였다. 구축한 각 시스템의 내용은 다음과 같다. (1)공장에너지관리시스템 수집한 에너지사용량 데이터를 관리$\cdot$분석용으로 가공하는 생에너지 지원용 어플리케이션 소프트웨어를 탑재하고있어 환경매니지먼트 시스템(ISO14001)을 실행하는 데에도 유용하다. (2)조명제어시스템 지금까지 단독기기였던 조도일정제어의 조광컨트롤러에 B/NET 전송기능을 탑재하여 스케줄 및 디맨드 감시에 의한 조광제어를 시행하여 한층 더 생에너지를 실현한다. (3)빌딩설비 감시시스템 빌딩의 에너지관리, 조명$\cdot$공조제어에 의한 생에너지화, 보전업무의 효율화$\cdot$생력화를 실현한다.