• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.57-65
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• 1997

In this study, a cutting force in the Ball-end milling process is calculated using Z-map. Z-map can describe any type of cutting area resulting from the previous cutting geometry and cutting condition. Cutting edge of a ball-end mill is divided into infinitesimal cutting edge elements and the position of the ele- ment is projected to the cutter plane normal to the Z axis. Also the cutting area in the cutter plane is obtained by using the Z-map. Comparing this projected position with cutting area, it can be determined whether it engages in the cutting. The cutting force can be calculated by numerical integration of cutting force acting on the engaged cutting edge elements. A series of experiments such as contouring and upward/downward ramp cutting was performed to verify the calculated cutting force.

• Korean Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.161-167
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• 1998

Cutting forces in ball-end milling of slanted surfaces are calculated. The cutting area is determined from the Z-map of the surface geometry and current cutter location. The obtained cutting area is projected onto the cutter plane normal to the Z-axis and compared with cutting edge element location. Cutting force is calculated by integration of elemental cutting forces of engaged cutting edge elements. Experiments with various slanted angles were performed to verify the proposed cutting force estimation model. It is shown that the proposed method predicts cutting force effectively for any geometry including sculptured surfaces with cusp marks and surfaces with pockets and holes.

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.13-21
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• 1995

This study was conducted to investigate the cutting mechanism of reciprocating knife of combine harvester. The cutting operation of reciprocating knife with the arrangement of the low-cutting and the double-cutting was demonstrated through cutting pattern diagram which was drawn by computer graphics. Various kinds and dimensions of reciprocating knives were analyzed using the developed program. The results are summarized as follows (1) The low-cutting type reciprocating knife was represented similar cutting characteristics to the standard type, but the maximum stalk-deflection was decreased as 1/2 level of the standard type. And the first ledger plate should be designed shorter than the second ledger plate. (2) The bunching area and the maximum stalk-deflection for the double cutting knife almost were not changed since cutting velocity ratio of 0.6, but the secondary cut were occurred at ratio of 0.8 and increased rapidly over these ratio. (3) The double cutting knife was recommended for the high speed combine, because its bunching area and the maximum stalk-deflection were decreased as 1/2 level of the standard type. (4) In order to maintain the proper cutting mechanism characterized by the bunching area, the maximum stalk-deflection and the secondary cutting length etc., the adequate cutting velocity at forward speed of 0.5㎧ to 1.2㎧ was from 0.3㎧ to 0.96㎧ for the double cutting knives.

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.3-12
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• 1995

This study was conducted to investigate the cutting mechanism of the reciprocating knife of combine harvester. The cutting operation of reciprocating knife was demonstrated through the cutting pattern diagram which was drawn by computer graphics. Various kinds and dimensions of standard-type reciprocating knives were analyzed by the developed program. The results are summarized as follows : (1) For the 50mm standard reciprocating knife, the bunching area and the maximum stalk-deflection were decreased rapidly according to the increase of cutting velocity ratio by 1.0 and decreased very slowly over this ratio. But, the secondary cut was occurred at ratio of 1.0 and increased rapidly over this ratio. (2) The 76mm standard knife showed better cutting mechanism than the 50mm, in two respects : the larger cutting area per one stroke and the lower revolutional speed of crank shaft for the same cutting velocity. (3) In respect to the bunching area and the secondary cutting length, the adequate height of 50mm standard reciprocating knife was 45~50mm. (4) In order to maintain the proper cutting mechanism, the adequate cutting velocity at forward speed of 0.5㎧ to 1.2m/s was from 0.4m/s to 1.2m/s for the standard knife.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.17-22
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• 2006

Zirconium is widely applied in industrial area. In this study, the exeperiments are performed to investigate the differences in cutting characteristics of zirconium coated material which deposited on cutting tool using physical vapor deposition(PVD). For comparison, TiN coated tool is used to compare with zirconium coated tool. Experimental results were compared for tool wear, surface roughness and cutting force. The tool wear of PVD coated bites is affected by the various cutting conditions. This new stuff 'zirconium coated tool' wears $33\%$ less and improves surface roughness $23\%$ more in various cutting conditions. Cutting force is analyzed by using various workpiece, and the research strongly confirms that 'zirconium' remains better condition than 'titanium'. As a result 'zirconium' coated tool can be performed far better than 'titanium' coated tool on metal cutting.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.212-219
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• 1998

During machining of dies and molds with sculptured surfaces. the cutter contact area changes continuously and results in cutting force variation. In order to implement cutting force prediction model into a CAM system, an effective and fast method is necessary. In this paper. a new method is proposed to predict mean cutting force. The cutter contact area in the spherical part of the cutter is obtained using Z-map, and expressed by the grids on the cutter plane orthogonal to the cutter axis. New empirical cutting parameters were defined to describe the cutting force in the spherical part of cutter. Before the mean cutting force calculation, the cutting force density in each grid is calculated and saved to force map on the cutter plane. The mean cutting force in an arbitrary cutter contact area can be easily calculated by summing up the cutting force density of the engaged grid of the force map. The proposed method was verifed through the slotting and slanted surface machining with various inclination angles. It was shown that the mean force can be calculated fast and effectively through the proposed method for any geometry including sculptured surfaces with cusp marks and holes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.67-71
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• 2012

The purpose of this study is to investigate cutting characteristics and wear behavior in FCD500 ductile cast iron turning with different cutting tools, tungsten-carbide and CBN. Mechanical property, cutting characteristics and the application to the real industrial area is the final purpose. FDC500 ductile cast iron is now widely used in the various commercial vehicle parts for increased machine abilities which accrue more tensile strength with lower hardness. Several studies have been fulfilled for the material and heat-treatment area, but few with the cutting characteristics and wear behavior in the turning area.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.73-81
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• 1993

In recent years, mould industry in machining requires to increase machining productivity and to reduce costs, To adapt this trend it is necessary to optimize machine condition, Even though many researches in this area introduced various way to set the optimal condition, still there are not enough. Therefore this research was done to select the optimal cutting condition for industry, and to develop the computer program to select the optimal cutting condition automatically. The result of this research will contribute to increase machining productivity of various mould companies with the automatic selection of optimal cutting condition.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.3
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• pp.203-212
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• 1993

This experiments were carried out to estimate the optimum final cutting date in autumn and the selection of highly adaptable varieties in mountainous pastures of Taekwalyong area. The evaluations were based on the data of varietal differences of dry weight of plant(DW) and yield components of the 1st cutting as affected by various final cutting dates of last autumn. Nine varieties of tall fescue Barvetia, Fuego. Demeter, Safe. Barcel, Forager, Johnstone, Enforcer and Stef. were used and 4 final cutting date of autumn were $C_1$, cut on 30 Sept. $C_2$, on 14 Oct. $C_3$, on 28 Oct. and $C_4$. on 11 Nov.. respectively. The results obtained were as follows: I . Between the dry weight of plant(DM) and yield components of 1st cutting were different by various final cutting dates of autumn. The dry weight of plant(DW) was significantly positive correlated with heading characteristics of the 1st cutting in earlier cuttings($C_1- C_3$) of autumn, but there was not significant correlated with heading characteristics of the 1st cutting in the latest cutting($C_4$) of autumn. 2. The variety of Forager with heavier weight of heading tiller(HTW) and dry weight of tiller(WT) showed the highest dry weight of plant(DW) of the 1st cutting in earlier cuttings($C_1-C_3$) of autumn, whereas the variety of Barcel with high number of tillers per plant(NT) showed a high dry weight of plant(DW) of the 1st cutting in the latest cutting($C_4$) of autumn. 3. Optimum final cutting date and critical period of mountainous pastures in Taekwalyong area were estimated in late September($C_1$) and middle October($C_2$), sespectirety. 4. The dry weight of plant(DW) of the 1st cutting was significantly negative correlated with final cutting dates in growth period of autumn.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1269-1278
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• 2013

The cutting area changes periodically in the end-milling process because of its form generation mechanism. In this study, the effects of the cutting area on end-milled side walls are studied by developing a cutting area model that simulates the area formed by engagement between a workpiece and a cutting edge of the end mill. To do this, the straightness profile of the side wall in the axial direction is investigated. Models for estimating the cutting area and the transition point, where the slope of the straightness profile changes suddenly, are verified from real end-milling experiments under various radial and axial depth of cut conditions. Through this study, it is confirmed that the final end-milled side wall is generated in the regions where cutting areas are constant and decreasing in the down-cut. Similarly, in stable up-cut, it is also generated in the regions where cutting areas are increasing and constant. It is found that the transition point appears when the region changes.