• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.320-330
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• 2018

Purpose: The aim of this study was to investigate the harvesting performance of a prototype small combine for buckwheat and adlay. Methods: The prototype small combine was designed and constructed. Its ratio of grain loss, ratio of output components in the grain outlet, and field capacity for harvesting buckwheat and adlay were analyzed through field tests. Results: The prototype small combine required a working width of about 0.6 to 0.7 m to harvest buckwheat. The maximum travel speed was about 0.36 m/. The total ratio of grain loss was about 21.6%, which consisted of 8.8% at the header and 12.8% at the dust outlet. The grain and the material other than grain (MOG) ratios at the grain outlet were 94.1% and 5.9% respectively. In the case of adlay harvest, the maximum working width was about 1.2 m, that is, two rows. The range of maximum travel speed was about 0.45 to 0.46 m/s. When adlay was harvested in one row, the total ratio of grain loss ranged from 36.3 to 42.8% according to the cutting height. The cutting height of 30 cm resulted in a higher total ratio of grain loss than 60 cm and 90 cm. When the cutting height was 60 cm, there was no significant change in the total ratio of grain loss according to the number of working rows and the stage of the primary transmission shift. The total ratio of grain loss ranged from 35.2 to 37.7%. The grain and the MOG ratios at the grain outlet ranged from 93.1 to 95.8% and from 4.2 to 6.9%, respectively. No significant difference was observed in relation to cutting height, number of working rows, and the stage of the primary transmission shift. Conclusions: The prototype small combine for harvesting miscellaneous cereal crops showed good potential for the efficient harvesting of buckwheat and adlay. However, to improve the harvesting performance, there seems to be a need to develop new crop varieties suitable for machine-based harvesting and improve the transmissions, reels, separation/cleaning systems.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.52-60
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• 1999

In this study the effect of roundness error with respect to the cutting conditions using the external cylindrical work piece by end mill cutting in a machining center was studied. the end mill used in this study is HSS coated with Ti-N which is of Ø 12-4 flutes. The material of workpiece is SM20C and cutting oil is used as a cooling flued The cutting experiments were carried out for the several cutting conditions(depth of cut height of end mill feed rate revolution per minute and cutting direction) and their roundness effects were compared using the least squares circle measuring method. The experimental results are summarized as follows : 1) The cutting depth is dominant for the roundness of a cylindrical work piece and the cutting speed must be determined precisely when the cutting depth is large 2) When the cutting direction in circular manufacturing is the same with the spindle rotation i.e up-cutting condition the surface roundness is also improved.

• Journal of Welding and Joining
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• v.14 no.5
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• pp.59-68
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• 1996

This study was aimed to characterize the laser cutting process for the cold rolled stainless steel sheet. The principal process parameters of the cutting process were applied to both the continuous wave form and the pulsed wave form for the laser output mode. The laser-oxygen cutting process and the laser-nitrogen cutting process were also considered to characterize the quality and efficiency of the cutting process. The laser-oxygen cutting process revealed the better productivity than the laser-nitrogen cutting process, since the laser energy and the exothermic oxidation energy exerted on the laser-oxygen cutting process simultaneously during the entire cutting process. However, the straightness of the cutting section, which was considered as the most important factors, was inferior to that of the laser-nitrogen cutting process due to the formation of chromum oxide on the cutting surface. Frequency and duration of the pulsed wave form act as the main factors for the better quality, When the frequency increased from 100 Hz to 200 Hz and the duty increased from 20% to 40%, the quality factors such as the height of dross and the surface roughness were improved remarkably. The increase in the frequency from 200 Hz to 300 Hz, on the other hand, revealed the less effective in the cutting quality.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.52-62
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• 2013

In order to obtain the relation between the cutting force and the process parameters in the chamfering process for the gear of a gear shaft, analysis of the process was performed with a simplified model instead of considering the whole actual 3-dimensional cutting situation produced between cutting tool and gear. The model divided the actual situation into the accumulation of hundreds of 2-dimensional layers with a small thickness in the direction of the height of gear and derived cutting force at a cutting position by accumulating each cutting force calculated in a layer. With proposed method to analyze the cutting forces in the chamfering process, it was revealed that the cutting position and size were exactly searched to calculate the cutting force in each layer. The total cutting force was the highest in the corner where the cutter encountered the gear first during the relative motion between them. The cutting forces were changed in proportion to the cutting parameters such as feed rate and trajectory.

• 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.

• Fire Science and Engineering
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• v.26 no.3
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• pp.60-66
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• 2012

In this study, it was evaluated the fire risk during welding cutting tasks. Welding-cutting machines are representatively used at construction sites. Inverter AC/DC TIG welding macnine and inverter air plasma cutting machine were used in experiments. Temperature of spreaded cinders was measured using a thermal camera. Cinder sizes and spread range were measured according to the height and input current. It was also evaluated the fire risk during welding-cutting process, when flammable materials were located around the working area. There were used hay, dust fence, urethane foam, vinyl, paper and oil as flammable materials. Temperature of spreaded cinders was reached at about $450^{\circ}C$. Cinders were spread approximately 4.7 m, when a worker carried out cutting process at 2.5 m height. The possibility of a fire is very high, when flammable materials were located around the working area.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.52-57
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• 1993

In this study, the inclined endmilling process with a 3-axis machining center using inalined jigs is introduced for the purpose of reducing overall Dies/Molds machining time and improving the machining accuracies. In order to analyse the cutting mechanism of a given endmill more accurateky, the unification of the cutting mechanism model of 3-different-kind endmills is examined by using the mose radius as a parameter. By adding radial runouts as a parameter which influences on surface roughness, the superposition method which defines the effective cusp heigh superposing the cutter mark height and the conventional cusp height is modified. And 3-D surface topography predicted in this paper looks like the surface normally observed in practice. Through machining experiments, the adequacy of the superposition algorithm was confirmed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.387-398
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• 1997

This experiment was to investigate the surface coverage, sward height and dry matter yield of 63 perennial ryegrass cultivars with control cultivar, orchardgrass(Potomac) at different cutting dates(May 25, July 5, August 20 and October 5), in order to select the adaptable cultivars of perennial ryegrass in the middle region of Korea. Four perennial ryegrass cultivars, E.V. Meadea, Aberystwyth S101, Raidor and Real, didn't survive afler sowing. Surface coverage of perennial ryegrass cultivars cut in August 20 was lower than others. Sward height of perennial ryegrass cultivars at each cutting dates was lower than that of orchardgrass. There were no significant differences in sward heights of each cutting date. Dry matter yield of perennial ryegrass cultivars cut in August 20 was lower than others. Total dry matter yield of Oakpark 6% Viktoria, Petra, G. Manawa, and Kangaroo Valley was fell in the range of 11.76 and 10.37t/ha while that of orchardgrass was 12.09t/ha. On the basis of total annual dry matter yield, the adaptability of perennial ryegrass cultivars was classfied as following.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.1
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• pp.22-32
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• 1985

Optimum pasture management during the summer season is an important factor to maintain good regrowth and persistence of pasture in Korea. This experiment was carried out to investigate the effects of the cutting management on the dead plant, weed appearance, regrowth and carbohydrate reserves in stubble, and dry matter yield of tall fescue dominated pasture during the mid summer season. For the test, a split plot design with 4 replications was treated with 2 different the third cutting times (July 12 and Aug. 4) as the mainplots, and 3 different cutting heights (3, 6 and 9 cm) at the third cut as the subplots, and the experiment was done at the experimental field of the Livestock Experiment Station, in Suweon, 1984. The results obtained are summarized as follows: 1. Considering the meteorological conditions during the experimental period, the temperature was a little higher by $2^{\circ}C$ than that of average year, especially the first and second decade of August were high. And the precipitation of 1984 tended to be low when compared with the average year. 2. Temperature of soil surface and underground tended to increase by $1-3^{\circ}C$ as the stubble height was low during the summer season. 3. Regrowth leaf length and leaf area after the third cut increased significantly with the high cutting height at the third cut. 4. A significant higher total nonstructural carbohydrate (TNC) content in stubble after the third cut was observed in the high stubble cut on July 12. The results indicate that the high stubble height reserves more carbohydrates for early regrowth stage after the third cut when compared with the low stubble. On Aug. 4, however, the recovery of TNC contents after the third cut was not effective due to high temperature and rainfall. 5. The percentage of dead plant after the third cut was found to be high with the low cutting height during the mid summer season (p<0.05). 6. With the low stubble height on July 12 cut, it was appeared that the percentage of weed was significantly increased (p<0.05), and main weeds appeared after the third cut were Echinochloa crusgalli>Digitaria sanguinalis>Cyperus iria>Rumex crispus, and so on. In case of cut on Aug. 4, weed appearance was no difference at three cutting heights. 7. Dry matter yield at the third cut was increased in the plot of cutting on Aug. 4 and stubble height (p<0.05). However, yields at the fourth and fifth cut were increased with high stubble height (p<0.05), regardless of harvest time. 8. In total dry matter yield after the third cut, there was no significant difference between the cutting time and forage yield. However, total yield on July 12 was increased with the high stubble height (p<0.05). 9. From the above results, it is suggested that the 9 cm cutting height during the mid summer season is the most effective for good regrowth, weed control and forage yield of tall fescue dominated pasture.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.124-131
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• 1995

In order to find out optimum seed production date according to different defoliation and flooding period of Italian ryegrass, this studies with Tetrone were canied out on the experimental field of Honam Crop Experiment Station from 1986 to 1988. Treatments included cutting date of Nov. 20 and Apr. 10 and flooding period of 5-25 days. In soil after experiment, organic matter, phosphate and silicate content increased, but potassium content decreased 0.16% than that before experiment. Heading and maturing date of Nov. 20 cutting were same with those of non cutting, those of Apr. 10 cutting lates 6 days to heading date and 2 days to maturing date. Plant height and culm length of Nov. 20 cutting were sirniller to those of non cutting, those of Apr. 10 cutting were shorter and panicle length have no difference between non cutting and cutting. Lodging of cutting treatment was reduced than that of non cutting. Lodgin was increased as flooding period was long, also loding of all treatment occured at 30 days after heading. Two cutting times of Nov. 20 and Apr. 10 have the most fresh yield, while non cutting have the most dry matter yield. Optimun seed productin date was considered to suitable when 35 days after heading (Jun. 14), at this time, seed production was 1,640 to 2,640 kg/ha. Also if flooding j u r y have, seed production was good between 10 days and 15 days after flooding.