• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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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.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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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.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.111-115
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• 1985

This experiment was conducted to investigate the effects of maturity and intake on digestibility of grass hay harvested at different dates. Hay was prepared from first-growth forage which cutting dates were: 4 June (vegetative, called early-cut) 30 June (heading, called late-cut). The grass hay fed to wethers at restricted and ad libitum levels of intake. The results obtained are summarized as follows: 1. As delay in cutting date, contents of crude protein and crude fat decreased, while fibre and lignin increased. 2. On ad libitum feeding of early-cut and late-cut hay, the DM intake were $82g/W_{kg}^{0.75}\;and\;68g/W_{kg}^{0.75}$ respectively. 3. There was no significant difference in dry matter digestibility of early-cut hay between restricted and ad libitum feeding, but dry matter digestibility was decreased markedly in ad libitum feeding when leaves fecal condition out of account. Digestibility of crude protein, organic matter and fibre contained in early-cut hay were tended to decrease slightly in ad libitum when compared with restricted feeding, but were not significantly. 4. Digestibilities decreased significantly with increase of intake in late-cut except for crude protein (P<0.05 or P<0.01). 5. In the comparison of digestibility for all composition, early-cut hay was higher (P<0.01) than late-cut hay.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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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.

• Explosives and Blasting
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• v.26 no.2
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• pp.99-107
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• 2008

This study, to reduce a ground vibration damage of the structures in an area adjacent to housing structures located closely above the tunnel section, is the ground vibration reduction instance of a tunnel blasting selectively applied the ground vibration-controlled blasting method (delay time applied blasting method, large center hole cut method, Line Drilling method, etc) with an originally planned blasting method connected, but with it's workability and economic efficiency is satisfactory, so, the results says the ground vibration-controlled blasting method on a similar condition is very effective, even if the applicability is depend on the blasting method and ground condition of the work area.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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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

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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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.