• 한국정밀공학회지
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• 제16권8호
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• pp.178-185
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• 1999

In tool condition monitoring systems, parameters should be set to a certain threshold. In many cases, however, the threshold is dependent on cutting conditions, especially the radial immersion ratio. In this presented is a method of on-line estimation of the radial immersion ratio in face milling. When a tooth finishes sweeping, a sudden drop of cutting force occurs. The force drop is equal to the cutting force that acting on a tooth at the swept angle of cut and can be acquired from cutting force signals in feed and cross-feed directions. Average cutting force per tooth period can also be calculated from cutting force signals in two directions. The ratio to cutting forces in two directions acting on a tooth at a certain swept angle of cut and the ratio of average cutting forces in two directions per tooth period are functions of the swept angle of cut and the ratio of radial to tangential cutting forces. Using these parameters, the radial immersion ratio is estimated. Various experiments are performed to verify the proposed method. The results show that the radial immersion ratio can be estimated by this method regardless of other cutting conditions.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1109-1115
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• 2023

The shell and tube-type heat exchanger was the most utilized in industrial field because of its simple structure and wide operation conditions and so on. This study was performed to investigate the characteristics of behavior of thermal flow according to operation condition of small-sized shell and tube-type heat exchanger. The operation conditions, here, were set up to flow rate of hot air with temperature of 100℃, number of baffle and cut rate of baffle(BCR) using numerical analysis. As the results, both mean relative pressure and relative pressure drop was increased with quadratic curve in case of less than BCR 25%, however, decreased linearly in case of more than BCR 25%. The collision with first baffle by flow velocity and temperature, of hot air, respectively, was depended on BCR. Further it showed that the behaviors between flow velocity and temperature were almost similar.

• 한국생산제조학회지
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• 제6권3호
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• pp.17-25
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• 1997

This paper aims to clarify the effects of grinding conditions on the grinding force, ground surface and chipping size of workpiece in surface grinding of various ferrites with the resin bond diamond wheel. The main conclusions obtained were as follows: In a constant peripheral wheel speed, the specific grinding energy is fitted by straight lines with grinding depth coefficient($\delta$) in a logarithmic graph. The effect of both depth of cut and workpiece speed on grinding energy becomes larger in the order of Mn-Zn, Cu-Ni-Zn and Sr. When using the diamond grain of the lower toughness, the roughness of the ground surface becomes lower. The ground surfaces show that the fracture process during grinding becomes more brittle in the order of Sr, Mn-Zn and Cu-Ni-Zn. The chipping size at the corner of workpiece in grinding increases with the the increases of the depth of cut and workpiece speed, and the decrease of peripheral wheel speed. The effect of both depth of cut and workpiece speed on chipping size becomes more larger in the order of Sr, Mn-Zn and Cu-Ni-Zn.

• 한국초지조사료학회지
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• 제5권2호
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• pp.111-115
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• 1985

본(本) 시험(試驗)은 예취시기(刈取時期)를 달리하여 조제(調製)된 건초(乾草)를 이용(利用)하여 예취시기(刈取時期)와 섭취량(攝取量)이 소화율(消化率)에 미치는 영향에 대하여 검토(檢討)하였다. 목초(牧草)는 6월(月) 4일(日)(영양생장기(榮養生長期))과 6월(月)30일(日)(출수기(出穗期))에 예취(刈取)된 1 번초(番草)로 건초(乾草)를 조제(調製)하였으며 이 건초(乾草)는 제한급여(制限給與)와 수준(水準)으로 급여(給與)하였다. 그 결과(結果)를 요약(要約)하면 다음과 같다 1. 예취시기(刈取時期)가 지연(遲延)됨에 따라 조단백질(粗蛋白質) 및 조지방함량(粗脂肪含量)은 감소(減少)하였고, 섬유질(纖維質) 및 lignin함량(含量)은 증가(增加)하였다. 2. 조기예취건초구(早期刈取乾草區)와 만기예취건초구(晩期刈取乾草區)의 건물섭취량(乾物攝取量)은 각각(各各) $82g/W_{kg}^{0.75}$과 $68g/W_{kg}^{0.75$이였다. 3. 조기예취건초구(早期刈取乾草區)에서 제한급여(制限給與)와 자유채식간(自由採食間)의 건물소화율(乾物消化率)에서는 유의차(有意差)가 없었으며, 배분상태(排糞狀態)를 고려(考慮)하지 않은 무제한급여(無制限給與)에서는 현저하게 감소하였다. 그리고 조단백질(粗蛋白質), 유기물(有機物) 및 섬유질소화율(纖維質消化率)에서도 유의차(有意差)는 없었으나 자유채식(自由採食)했을 때가 감소(減少)하는 경향을 보였다. 4. 만기예취건초구(晩期刈取乾草區)의 경우 조단백질소화율(粗蛋白質消化率)을 제외한 전성분(全成分)의 소화율(消化率)이 섭취량(攝取量)의 증가(增加)에 따라 유의(有意)하게 감소(減少)하였다. (P<0.05 혹은 P<0.01) 5. 조기예취건초구(早期刈取乾草區) 와 만기예취건초구간(晩期刈取乾草區間)의 소화율(消化率)을 비교하면 1%수준(水準)의 유의차(有意差)가 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권10호
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• pp.1465-1471
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• 2004

A trial was conducted to determine the effect of abrasive strips and abrasive paint in layer cages on claw length and claw sharpness, foot condition, feather cover and mortality of hens. During the preparation of the cages for the experiment it was simpler and took less time to apply the pre-prepared paint with a spatula to the egg guard compared to sticking the abrasive strips onto the egg guard. Fitting the strips took longer because it had to be cut from a 25 mm roll, cut into the appropriate lengths, the tape backing removed and then stuck onto the egg guard section. Abrasive paint was more effective as a claw shortener than abrasive strips. The birds using the abrasive paint had the shortest (p<0.05) claw length and lowest (p<0.05) claw sharpness. One of the original reasons for reducing claw length with claw shorteners was to reduce mortality by minimising skin skin abrasions caused by the claws. Surprisingly hen mortality from prolapse and cannibalism was higher (p<0.05) in cages fitted with abrasives. There are no other reports in the literature showing an increase in prolapse and cannibalism from hens using abrasives.

• 화약ㆍ발파
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• 제26권2호
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• pp.99-107
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• 2008

본 발파시공사례는 터널노선 상단부에 위치한 주택구조물 근접지역에서 구조물 진동피해 저감을 위해 당초 설계의 발파공법과 결부시켜 시공성과 경제성이 양호한 진동제어발파방법(다단식발파, 선대구경 심빼기, Line Drilling공법 등)들을 조합하여 단계적으로 추가시키는 굴착공법들을 검토 적용한 터널발파의 진동 저감사례이다. 따라서 시공에 대한 적용성은 발파방법이나 지반조건 등에 따가 진동 저감에는 다소의 차이는 있을 것으로 사료되나 유사조건의 현장 적용은 매우 유용할 것으로 판단된다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.567-572
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• 2000

From the experimental study of W-EDM for alloyed steel, the characteristics such as Hand Drum Form and surface roughness have been observed and evaluated for various conditions. In square hole, the increase of IP as to made condition, the calculate high value of surface roughness. Also compare dimensionless square hole with circle hole' graph, In circle hole, if a value of surface roughness IP 6 in a side of circle it show a 0.4${\mu}{\textrm}{m}$ and in IP 8, 0.6${\mu}{\textrm}{m}$, in IP 10, 0.7${\mu}{\textrm}{m}$, in IP 12, 0.8${\mu}{\textrm}{m}$ higher than before. This figure show the surface roughness is higher than before, because a table move in either X-axis or Y-axis in square hole, on the contrary, in circle there table move in X-axis and Y-axis at the same time. hand drum form getting small when wire tension increase 1000gf to 1500gf, at the same working conditions. The smaller of off time, the maller of hand drum form in same condition and same wire tension. but if you compare square hole with circle hole' graph, hand drum form displayed in maintained term of working condision, on the contrary, in case of square hole variation of hand drum form is more increase than a grow of IP

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.192-197
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• 2002

In this study, examined the cutting characteristics of alumuminum alloy AC8A-T6 that is used to present car piston materials. And in been holding materials machining empirically escape as result that experiment comparison changing the cutting speed and feed on various condition to choose efficient machining condition. The following results can be summarized from this research. 1. As the cutting speed decreased, principal cutting force and thrust cutting force is increased, and reason that cutting force interacts greatly in the low cutting speed is thought by result by BUE's stabilization. 2. The feed speed and cutting speed increase, friction factor is decrescent and the cause appeared the thrust cutting force is fallen than cutting force relatively because chip flow according to increase of the feed rate is constraint. 3. Though specific cutting resistance grows cutting area and the feed rate are few, the cause was expose that shear angle decreases by rake face of tool gets into negative angle remarkably as wear of a cutting tool or defect part of workpiece is cut. 4. Cutting speed do greatly depth of cut is slow, surface roughness examined closely through an experiment that becomes bad, and know that it can get good surface that process cutting speed because do feed rate by 0.1mm/rev low more than 250m/min to get good surface roughness can.

• 한국생산제조학회지
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• 제7권3호
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• pp.43-50
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• 1998

In the use of CNC machine tool, the unmanned production system has been growing in the manufacturing field. Thus, it is necessary to monitor adequate tool fracture during the cutting process efficiently. This experimental study is intended to investigate the development of flank wear in sysnchronous turning of differential materials(Aℓ/GC) which is used in industrial application and it is acknowledged as a machine to difficult material. In cutting process change of velocity, change of feed, and change of depth of cut were investigated on the effect of flank wear, and slenderness ratio is also investigated. The conclusions of this paper are summarized as follows; 1.Under the high cutting speed condition, the flank wear is affected by the feed and depth of cut. but the influence of feed on the flank wear is larger than the depth of cut and that is reduced when the velocity is low. 2.Under the high cutting speed, as the smaller slenderness ratio is, the shorter tool life is under the lower cutting speed, the effect of slenderness ratio on the flank wear is low. 3.Using the characteristics of cutting force, the flank wear of a tool can be detected 4. Investigating the development of flank wear, there are almost no differences between the characteristics of cutting force and feed force. Finally, these data from the differntial materials cutting process will be used in the basic field of precision and economic cutting process.

• 대한기계학회논문집
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• 제18권9호
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• pp.2225-2233
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• 1994

In order to improve the cutting ability of face mill, a model for optimal cutter shape was developed to minimize resultant cutting force by combing cutting force model and optimal technique. Wear test and surface roughness test for optimized and conventional cutter were performed. The new optimized cutter shows longer tool life of 2.29 times than conventional cutter in light cutting condition and 2.52 times in heavy cutting condition. The surface roughness of workpiece by optimized cutter is improved in heavy cutting condition, but deteriorated in light cutting condition in comparison with conventional cutter. The surface profiles of workpiece were analyzed by Fourier transformation. The distribution of cut lay left on workpiece by optimized cutter is more regular than that by the conventional cutter.