• Journal of Biosystems Engineering
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• 제43권4호
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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.

• 한국생산제조학회지
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• 제8권4호
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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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• 제14권5호
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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.

• 한국기계가공학회지
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• 제12권1호
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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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• 제20권1호
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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.

• 한국화재소방학회논문지
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• 제26권3호
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• pp.60-66
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• 2012

본 연구에서는 건설현장 등에서 주로 사용되는 용접 절단기의 작업시 화재위험성을 평가하였다. 실험에는 인버터 AC/DC TIG 용접기와 인버터 에어프리즈마 절단기가 사용되었다. 용접 절단 작업시 비산되는 불티의 온도를 측정하였다. 작업높이와 입력전류의 변화에 따라 비산된 불티의 크기 및 비산범위를 측정하였다. 또한, 용접 절단기 화재원인 중 가장 높은 비율을 차지하는 가연물 근접방치에 의한 화재위험성을 평가하였다. 가연물로는 건초, 방진막, 우레탄폼, 비닐, 종이, 유류가 사용되었다. 용접 절단 작업시 불티의 온도가 최대 $450^{\circ}C$까지 상승하였다. 2.5 m 높이에서 절단 작업시 불티가 최대 4.7 m까지 비산되었다. 용접 절단 작업시 주위에 가연물이 존재할 경우 비산된 불티에 의해 가연물에 착화되어 화재로 발전할 가능성이 매우 높다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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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.

• 한국초지조사료학회지
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• 제17권4호
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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.

• 한국초지조사료학회지
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• 제5권1호
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• pp.22-32
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• 1985

본(本) 연구(硏究)는 고온기(高溫期) 초지(草地)의 예취관리(刈取管理)에 관(關)한 연구(硏究)로서 여름철 고온기간중(高溫期間中) 예취시기(刈取時期)와 예취(刈取)높이가 tall fescu 우점초지(優占草地)의 목초고사(牧草枯死), 잡초발생(雜草發生), 재생(再生)과 저장탄수화물함량(貯藏炭水化物含量) 및 수량(收量)에 미치는 영향을 구명(究明)하여 고온기(高溫期)의 적절한 예취방법(刈取方法) 모색하기 위해 실시(實施)되었다. 본(本) 시험(試驗)은 3차(次) 예취시기(刈取時期)(7월(月) 12일(日), 8월(月) 4일(日))를 주구(主區)로 하고 3차(次) 예취시(刈取時) 예취(刈取)높이(3, 6, 9cm)를 세구(細區)로 하여 4 반복 분할구 배치법으로 설계(設計)하였으며, 1984년도(年度) 수원(水原) 축산시험장(畜産試驗場) 초지시험포(草地試驗圃)에서 수행(遂行)된 결과(結果)의 요약(要約)은 다음과 같다. 1. 시험기간중(試驗期間中) 기상(氣象)을 요약(要約)하면 기온(氣溫)은 평년(平年)에 비해 $1{\sim}2^{\circ}C$높았으며 특(特)히 8월(月) 상(上) 중순(中旬)의 기온(氣溫)이 높았다. 강수량(降水量)은 7월(月) 상순(上旬), 8월(月) 하순(下旬) 및 9월(月) 상순(上旬)을 제외하고는 평년(平年)에 비해 적었다. 2. 고온기시(高溫期時) 지표(地表) 및 지중(地中)(10cm)온도(溫度)는 3차(次) 예취시(刈取時) 예취(刈取)높이가 낮을수록 높아지는 경향이었다(지표온도(地表溫度) : $2{\sim}4^{\circ}C$, 지중온도(地中溫度) : $1{\sim}2^{\circ}C$) 3. 3차(次) 예취후(刈取后) 예취(刈取)높이별(別) 재생초장(再生草長)과 재생엽면적(再生葉面積)은 예취(刈取)높이가 높을수록 빠른 생장(生長)을 보였다. 4. 3차(次) 예취후(刈取后) 그루터기내(內) 저장탄수화물(貯藏炭水化物)(TNC) 함량(含量)은 7월(月) 12일구(日區)가 8월(月) 4일구(日區)에 비해 회복이 빨랐으며 그 중 9cm 예취(刈取)높이구(區)에서 가장 빠른 회복을 보였고, 3cm구(區)가 가장 늦었다. 8월(月) 4일구(日區)에서는 고온(高溫)과 강우(降雨)로 인해 TNC의 회복이 더딘 것으로 생각되며 3cm높이구(區)에서 회복이 가장 늦은 경향을 보였다. 5. 고온기간(高溫期間)인 3차(次) 예취후(刈取后) 목초고사율(牧草枯死率)은 예취(刈取)높이가 낮아질수록 증가하였다(P<0.05). 6. 3차(次) 예취시(刈取時)에는 전체 시험포장에서 잡초발생(雜草發生)이 거의 없었으나 4차(次) 예취(刈取) 시(時)에는(7월(月) 12일구(日區)) 3cm구(區)에서는 60%의 잡초율(雜草率)을 보여 주었으며 6, 9cm로 예취(刈取)높이가 높아짐에 따라 잡초율(雜草率)은 21, 7%로 각각 감소하였다(P<0.05). 이는 5차(次) 예취시(刈取時)에도 비슷한 경향을 보였으며 주요발생잡초(主要發生雜草)로는 피>바램이>소리쟁이, 방동산이 등의 순으로 나타났다. 그러나 8월(月) 4일구(日區)에서는 예취(刈取)높이별(別) 잡초발생차이(雜草發生差異)는 크지 않았다. 7. 고온기시(高溫期時) 건물수량(乾物收量)(3차(次))은 8월(月) 4일구(日區)가 7월(月)12일구(日區)에 비해 많았으며, 예취(刈取)높이가 낮을수록 증가하였다(P<0.05). 그러나 4차(次)와 5차(次) 예취시(刈取時) 수량(收量)은 刈예취시기별(刈取時期別) 차이(差異)는 없었으나, 3차(次) 예취시(刈取時) 예취(刈取)높이가 높을수록 증가하였다(P<0.05). 8. 재생수량(再生收量)(4 + 5차(次))은 예취시기(刈取時期)에 관계없이 3차(次) 예취시(刈取時) 예취(刈取)높이가 높을수록 증가하였으며(P<0.05). 3, 4, 5차(次) 총건물수량(總乾物收量)을 볼 때 7월(月) 12일구(日區)에서는 예취(刈取)높이별(別) 차이(差異)가 인정되었으나(P<0.05), 8월(月) 4일구(日區)에서는 차이가 없었다. 9. 본(本) 시험(試驗)의 결과(結果)를 종합(綜合)하여 볼 때 여름철 고온기시(高溫期時) 목초(牧草)의 양호(良好)한 재생(再生)과 잡초발생억제(雜草發生抑制)를 위해서는 예취시기(刈取時期)에 관계없이 9cm의 높은 예취(刈取)높이가 바람직한 것으로 생각된다.

• 한국초지조사료학회지
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• 제15권2호
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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.