• Journal of Biosystems Engineering
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• 제33권2호
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• pp.83-93
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• 2008

In order to save labor and cost, direct seeding has been considered as an important alternative to the machine transplanting in rice cultivation. Current direct seeding machines for rice in Korea drill irregularly under various operating conditions. This study was conducted to develope a precision seeder which enables the accurate, even-spaced in row placement of rice seeds at uniform depths of 3-4 cm on dry paddy. Design, construction and performance evaluation of the precision seeder were carried out. The tractor rear-mounted type 8-rows precision seeder which performs seeding in addition to fertilizing, ditching, and rotary tilling works on dry paddy was developed. Main components of the seeder were ditcher and leveller, rotary tiller, powered roller type furrow opener, seeding device, powered roller type furrow covering and firming device, hydraulic unit, seeding speed control system, power transmission system, hitch and frame. Ditching, furrow opening, and seed covering and firming performances were good and seeding depths of 2-4 cm could be maintained. Planting accuracies and planting precisions were within 13.6%, and 31.2%, respectively, for planting space of 15 cm, and seeding velocity of 0.5 m/s. These mean variations of average planting space were within 2.1 cm, and 90% of seeds in a hill were seeded within 4.7 cm of hill length, respectively. Error ratios between setting planting space and measured average planting space were shown within 6.7%. Therefore the seeder showed good planting performance up to seeding velocity of 0.5 m/s in field tests. And field capacity of the seeder was about 0.28 ha/hour.

• 농업과학연구
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• 제41권4호
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• pp.259-264
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• 2014

This research was conducted to find design factors of seed metering device for developing seeder. It can be sowed precisely 1~3 seeds of Foxtail millet & Sorghum. To obtain fundamental information for designing seed metering device, we conducted adaptability test of the existing seeder in Foxtail millet & Sorghum. Major findings were as followings. Except of Model-A which was adapted sorghum(by seeding metering cup of width 3.9mm and length 4.5mm), seeders which were used in experiment showed that high value of miss-planted rates and more than four-planted rates. So to enhance precision of seeding in Foxtail millet & Sorghum, existing seeders were considered necessary by some supplementation.

• Journal of Biosystems Engineering
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• 제28권6호
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• pp.525-530
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• 2003

This study was carried out to develop a vacuum nozzle seeder for the automation of large seeds sowing of fruit vegetables and rootstocks. Moreover, the seeding efficiency was examined to find the optimum operating condition considering high precision seeding. The important operating factors for high seeding rate were typically nozzle diameter and absorbing vacuum pressure. The optimum nozzle diameters were found 1.5, 1.5 and 2.0 mm for Chambak, Tuktozwa and Hukjong while the optimum vacuum pressures were 8.0㎪, 10.6㎪ and 5.3㎪, respectively. Under the optimum operating condition, the results indicated that the maximum seeding rates were 97.6％, 98.8％ and 97.6％ respectively for Chambak Tuktozwa and Hukjong. The vibrating acceleration of the hopper did not make any significant effects on the seeding rate when the vacuum pressure reached 8.0㎪ and the sowing rate became higher with lighter seed. As the seed became heavier, the larger diameter of nozzle was recommended 1.5mm of the nozzle diameter was found to be applied for the experimental seeds. The vacuum pressure was also found 8.0㎪ - 13.3㎪ at that time.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.761-767
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• 1993

A precision planting system using computer controlled technology for mulching cultivation was developed and tested . The system consisting of a micro-computer, several optical fiber sensors and control actuators realized the mechanization of the precision planting operation. The film hole positions, existences of a seed on shutter were detected and the planting speed was measured. The shutter opening mechanism and a seed metering device driven by a stepping motor were controlled, automatically . The planting timing of the shutter opening mechanism were analyzed from a video camera motion analysis, theoretically. The results showed a sufficient accuracy of a seed planted into the center a film hole with a variety of planting speeded. The gravity point positions in film hole of seeds planted by the system just were within the area of +-5mm of the hole center when the hole diameter was 40mm.

• 한국정밀공학회지
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• 제19권2호
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• pp.106-113
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• 2002

Stencil is used normally as a mask for seeder pasting on pad of PCB. The objective of this study is to develop stencil cutting system and determine optimal conditions which make good-quality stencil by using a Nd:YAG laser. The effects of process parameters such as laser power, type of mask, gas pressure, cutting speed and pulse width old the cut edge quality were investigated. In order to analyse fille cut surface characteristics(roughness, kerf width, dross) optical microscopy, SEM photography and roughness test were used. As a result, the optimal conditions of process parameters were determined, and the practical feasibility of the proposed system is also examined by using a commercial Gerber file for PCB stencil manufacturing.

• 한국작물학회지
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• 제26권4호
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• pp.293-297
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• 1981

맥류시험에 있어서 표본추출 체계를 확립하기 위하여 1979/80년 맥류연구소의 포장에서 실시한 몇가지 소맥재배양식에 대한 표본단위의 크기 및 주어진 정도를 위한 표본수 결정을 시도하였던 바 그 결과를 요약하면 다음과 같다. 1. 소맥의 수수에 대한 변이계수는 휴입광철파를 제외하고는 맥류수량의 평균변이계수와 거의 같았다. 2. 수수의 변이계수와 표본단위의 크기에 대한 회귀계수는 유입광철파를 제외하고 모두 1% 수준에서 유의성을 보였다. 3. 표본단위의 크기는 재배양식에 따라 차이가 크며 변이계수 15%를 허용한다면 협폭파, 관행 및 Drill 파는 각각 0.40, 0.17 및 0.11$m^2$, 로 추정되며 답리작의 유입광철파는 0.55$m^2$, 로 추정되었다. 4. 표본단위간 변이가 심하여 시험오차의 분산성분이 영인 조건하에서 CV=12%를 위해서 2반복인 경우는 구당 2개의 표본단위, 4반복민 경우는 구당 1개의 표본단위로 충분한 것으로 추정되었다.