• 대한기계학회논문집
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• 제7권2호
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• pp.161-167
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• 1983

In this study the phenomenon of cutting stress which arises on cutting tools and work pieces in cutting process is investigated by rake angle of cutting tools and feed for this measurement, P$_{s}$-1 (high modulus, photolastic Inc.) was used as a cutting tool, P$_{s}$-3 (medium modulus, photolastic Inc.) was used as work piece and reduction apparatus was attached to the head stock, and orthogonal cutting was adapted as a cutting method and transparent glass was used to block the strain in the orientation of thickness. The followings are the results of this study. (1) Photoelastic experimental equipments have made it possible to make dynamic measurement and analyze stress distribution in cutting tool and work piece surface which has hitherto been conducted only in static measurement and analyzing method. (2) The maximum stress arising at tools and work pieces in cutting process is on the tool edge tip, and the maximum stress arising on the tip of cutting tools is equal to that on the contacting area of work pieces in values. (3) The distributions of maximum shear stress on certain parts of the cutting tools and work pieces are as follows; for cutting tools, .alpha.=12.deg., .alpha.=0.deg., .alpha.=-12.deg. in order, and for work pieces, .alpha.=-12.deg., .alpha.=0.deg., .alpha.=12.deg. in opposite order.der.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.84-91
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• 2003

In metal cutting operation, it is very important that predict cutting force and work surface. Vibration is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. When vibration on, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in machining center without cutting fluid to investigate the phenomenon of vibration. In the experiments, accelerometers were set up at the tail stock and tool holder and signals were picked up. Surface roughness profiles are generated under the ideal condition and the occurrence of vibration based on the surface shaping simulation model.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.184-189
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• 2003

In metal cutting operation, it is very important that predict cutting force and work surface. Vibration is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. when Vibration occurs, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in machining center without cutting fluid to investigated phenomenon of the Vibration. In the experiments, accelerometers were set up at the tail stock and tool holder and the signals were picked up. In this paper, surface roughness profiles will be generated under the ideal condition and the occurrence of the vibration based on the surface shaping simulation model.

• 한국작물학회지
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• 제46권3호
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• pp.176-179
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• 2001

Source와 sink의 상대적 크기가 다른 고구마 품종간 이면접목을 통하여 생육에 미치는 고구마의 source와 sink의 상호관계를 분석함으로써, 고구마의 품종육성 및 재배법개선에 필요한 기초자료를 얻고자 수행한 결과를 요약하면 다음과 같다. 1 만장, 괴근수는 접목에 의하여 감소되었으며, 접목조합에 따라서 차이가 있었다. 2. 지상부의 생육은 접수, 지하부의 생육은 대목의 영향을 많이 받았다 3. 주만장과 괴근수에 대한 접목효과, 접수와 대목의 효과와 이들 간의 상호작용은 모두 유의성이 있었다. 4. 상저비율은 보통삽식＞자가접목＞이면접목 순으로 높았다.

• 산업경영시스템학회지
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• 제33권3호
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• pp.30-39
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• 2010

This paper considers a problem of optimizing torch paths to cut stock plates nested with open contours. For each contour, one of the two ending points is to be selected as a starting point of cutting with the other being the exit point. A torch path is composed of a single depot and a series of starting and ending points of contours to be cut. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem. To solve the problem, a hybrid genetic algorithm with the local search of torch paths is proposed. The genetic algorithm is tested for hypothetical problems whose optimal solutions are known in advance due to the special structure of them. The computational results show that the algorithm generates very near optimal solutions for most cases of the test problems, which verifies the validity of the algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.552-552
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• 2000

In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problem. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional cutting stock on the Auto-CAD system. Therefore, this research can be called "pre-nesting"

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.1068-1072
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• 1997

This work deals with on investigation the influence of various additives to a base stock cutting fluid in order to develop a better deep hold drilling. This investigation has been aiming at developing an oil which gives a maximum cutting efficiency at a minimum wear rate of the tool and the guiding pads. The purpose of study is to analyze how guide pad of tools, workpiece and the change of contained quantity of extreme pressure additive in cutting fluids have effects on the hold over size of cutting hole, surface roughness of workpiece,wear rates of guide pad and roundness during the deep hole machining of SM55C with solid BTA drill by using BTA drilling system through experiment. Conclusion reached is as follows. It has been proved that the contained quantity of surphur more affects machinability than that of extreme pressure additive of chlorine of cutting fluid in BTA drilling during Deep Hole Drilling. Considering its base oil, the the contained quantity of extreme pressure assitive of surphur can be different, but it's judged that the range of 1.5 ~ 2.0% is suitable to machinability for workpiece in BTA drilling. Regarding guide pad, it's judged that the reduction of wear is possible in propotion to the contained quantity of exrreme pressure additive of chlorine against supporting of cutting force and Bumishing operation of machining parts in cutting.

• 대한기계학회논문집A
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• 제29권10호
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• pp.1416-1429
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• 2005

In order to meet the increasing competitive pressures coupled with higher demands for component quality, whirling machines have been at the cutting edge of the automobile industry for more than 25 years. The hard whirling process can save on machining time and operation elimination. Hard whirling is done dry, without coolant. The chips carry away nearly all of the heat during cutting, leaving the workpiece cool and minimizing any thermal geometry variations. The surface finish and profile accuracy are close to grinding quality. Whirling machines usually consist of four major parts; 1) loading system that requires the necessary axial speeds, 2) head stock that needs high precision clamping and positioning system at the chuck and tailstock, 3) whirling unit that demands the high cutting speeds and cutting power fer cutting deep thread profiles and 4) unloading system that requires an easy workpiece unloading. Also, capabilities of the whirling machine can be improved by attaching a vision system to the machine. Most of whirling machines in Korean automobile industry are imported from the Leistritz company, Germany and the Hasegawa company, Japan. Tn this paper, a basic research will be performed to improve and enhance the existing whirling machines. Finally, a new Korean whirling machine will be proposed and developed.

• 한국컴퓨터정보학회논문지
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• 제18권7호
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• pp.149-155
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• 2013

일반적으로 재료절단 문제는 재료를 절단할 수 있는 패턴을 찾고 선형계획법으로 최적의 패턴 수를 찾는다. 그러나 패턴 수는 일반적으로 지수적으로 증가하기 때문에 사전에 모든 패턴을 고려하는 것은 비현실적인 것으로 알려져 있다. 본 논문은 Suliman의 실현 가능 패턴을 구하는 방법을 적용하여 사전에 패턴을 구하는 방법을 적용하였다. 또한, 실현 가능 패턴들을 대상으로 선형계획법이나 근사 알고리즘을 적용하지 않고 정확한 해를 다항시간으로 얻는 방법을 제안하였다. 제안된 방법은 실현 가능 패턴들 중 모든 요구의 1st 발생 빈도가 손실량 0에 모두 분포하는 경우와 다양한 손실량에 분산되어 분포하는 경우로 구분하여 패턴 수를 분배하는 방법을 적용하였다. 제안된 알고리즘을 2개의 데이터에 적용한 결과 모든 데이터에서 정확한 해를 구하는데 성공하였다.

• 대한안전경영과학회지
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• 제3권4호
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• pp.113-122
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• 2001

This study is to examine the effect of layoff on shareholders' wealth. Firms make layoff decisions by reason of cost cutting, lower performance, demand decline, restructuring. Therefore, I think that stock market responds to layoff positively, since the firm's labor productivity and profitability is improved after execution of layoff, I find that layoff variables effect on abnormal return positively in regression analysis. This means that layoff sends positive signal to the stock market for the firm's future performance. Therefore, layoff has a good effect on shareholders' wealth.