• 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.

• 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 the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.182-188
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• 1994

This expermintal study is intended to investigate he development of flank wear in turning os SUS304 which is used in industrial applications and is acknowledged as a machining difficult material. In cutting process, change of velocity, change of feed, and change of depth of cut were investigated about the effect of flank wear, and slenderness ratio is also investigated. The variations of unit cutting force with the change of rake angle and the change of uncut chip area are observed. The friction angles are calculated for the change friction force and observed. The friction angles are calculated for the change friction force and normal forcd on the different rake angles. From this experimental study, the following results can be said. 1. Under the high cutting speed condition, the flaank wear is affected by the feed and depth of cut, but the influence of feed and depth of cut to the flank wear is reduced when the velocity is low. 2. The smaller slenderness ratio is, the shorter the tool life results in high cutting speed, and the lower cutting speed is, the lower the effect of slenderness ratio to the flank wear is. 3. Using the characteristics of force-RMS, the flank wear of a tool can be detected. There are almost no differences between the RMS characteristics of cutting force and feed force.

• 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.

• Food Engineering Progress
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• v.21 no.2
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• pp.110-115
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• 2017

This study aimed to identify milling characteristics depending on the number of a cutting roller's air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be $38{\pm}0.5$ in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and $14.6^{\circ}C$ which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.

• Geomechanics and Engineering
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• v.29 no.3
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• pp.359-368
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• 2022

Undercutting using an actuated disc cutter (ADC) involves more complex cutting mechanism than traditional rock cutting does, requiring the application of various new cutting parameters, such as eccentricity, cutter inclination angle, and axis rotational speed. This study presents cutting-edge laboratory-scale testing equipment that allows performing ADC tests. ADC tests were carried out on a concrete block with a specified strength of 20 MPa, using a variety of cutting settings that included penetration depth (p), eccentricity (e), and linear velocity (v). ADC, unlike pick and disc cutting, has a non-linear cutting path with a dynamic cutting direction, requiring the development of a new method for predicting cutting force and specific energy. The influence of cutting parameters to the cutter forces were discussed. The ratio of eccentricity to the penetration depth (e/p) was proposed to evaluate the optimal cutting condition. Specific energy varies with e/p ratio, and exhibits optimum values in particular cases. In general, actuated undercutting may potentially give a more efficient cutting than conventional pick and disc cutting by demonstrating reasonably lower specific energy in a comparable cutting environment.

• Journal of Welding and Joining
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• v.5 no.1
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• pp.23-33
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• 1987

Plasma arc cutting is a fusion cutting process in which a gas constricted arc is employed to produce high temperature, high velocity jet at the workpiece. Even though the plasma arc cutting has been wid¬ely used in the industry, very little work has been done on the analysis of the process. In this paper, the kerf width was numerically analyzed by soving the temperature distribution in base metal under consideration of the latent heat effect. In modelling the heat flow problem, the heat intensity of the plasma arc was assumed to have a Gaussion distribution in the transverse direction and expone¬ntially decreasing in the thickness direction. The thermal efficiency and the heat input ratio of the top surface were experimentally deterimned for various thickness and cutting conditions, and used in numerical calculation of the kerf width. The experimental results were in eonsiderabely good agreement with the theoretically predicted kerf width.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.57-58
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• 2006

A Simulation model is developed to minimize the path tracking errors when the non-circular cutting is done by a VCM(voice coil motor) driven tool. The relationship between PWM(Pulse Width Modulation) duty ratio and velocity of voice coil motor is theoretically derived from combining the circuit equation for the coils and the motion equation for the magnetic rod of the voice coil motor. The path tracking errors are showed differently according to the rotational speed, the number of segments and the control period in digital control. Given a required accuracy in the non-circular cutting, the optimal values for those parameters are determined based on the developed simulation model.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.576-581
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• 2012

A 23 W continuous wavelength $CO_2$ laser system exited by a high-frequency LCC resonant converter is adapted to cut a biodegradable rope fabricated with polybutylene succinate. As the biodegradable rope consists of three twisted strands, the thickness changes relative to the position of the laser beam and we thus propose a method to determine exact cutting depth. In order to obtain the parameters related to the rope cutting, the experimental and theoretical cutting depths are compared and analyzed for a range of laser heat sources. The melted thickness and groove width of the cut biodegradable rope are also examined. The proposed theoretical cutting depth depends on the incident power and target velocity ratio. From these experimental results, the biodegradable rope with a diameter of 22 mm can be cut with a heat source of 50 J/cm resulting in a melted thickness of 1.96 mm and a groove width of 0.65 mm. The laser system is shown to be perfect tool for the processing of biodegradable rope without the occurrence of raveling.

• Journal of Biosystems Engineering
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• v.30 no.4 s.111
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• pp.220-228
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• 2005

This study was conducted to investigate the main factors that contain a rotating velocity ratio between wheel and conveyor belt, a tilt angle of conveyor belt and a rotating velocity of a dick cutter for mechanization of Chinese leek harvest. In the survey on the cultivation of Chinese leek, row spacing of 350 m and cutting height of 10 mm from the ground were set up for field tests. Test equipment was designed to cut, pick up and convey Chinese leek one row by one row. From the results of material tests, pick-up height of conveyor belt was set up at $60\~90m$ from the bottom, and the strain and stress at rupture of Chinese leek was 0.487 m/m and 0.01078 MPa. An elastic coefficient of the rubber (Neoprene) of conveyor belts was 1.1077 under the strain of 0.3 nym. from the results of field tests, the tilt angle of conveyor belt was the range of $25^{\circ}\~30^{\circ}$ under consideration far space of container, the velocity ratio between vehicle and conveying belt was 1 to 2.4~1.7 at 0.1~0.3 m/s of vehicle, and optimum rotating velocity of the disk cutter was 34.8 m/s or more under consideration for soil friction.