Design, Fabrication and Evaluation of Electric Forage Chopper with Adjustable Helix Angle

Authors
M. Jamshidpouya 1
G. Najafi 2
T. Tavakoli Hashjin 2
1 Mechanics of Biosystem Engineering Department, Agricultural faculty, Tarbiat Modares University
2 Department of Biosystems Engineering, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
Abstract
In this study, we aimed to design and make an electric forage chopper having a cylinder type cutterhead. In recent years, several models of forage chopper have been manufactured but each of these machines has had problems such as type of power supply system, type of cutting mechanism and feeding mechanism, lack of safety, etc. These problems were solved in this study. In the device that was manufactured in this research, feed rolls rotational speed, rotational speed of the cutting cylinder, blades’ helix angle and blades’ rake angle was adjustable. So, with these capabilities, these variables can be optimized for any kind of forage, and this information can be used to design and construct suitable machines for crushing any kind of forage. Alfalfa was used to test the machine, where its test matrix was determined using Response Surface Methodology (RSM) modeling method. The results showed that, on average, power requirements for chopping alfalfa was decreased from 12.6 to 9.7% by increasing the helix angle from 0° to 10° and from 10° to 20°, respectively. As rotational speed of the cutting cylinder increases from 500 to 800 rpm, the power used for chopping forage increases by about 56 W. In the conducted tests, maximum power requirements for chopping alfalfa was roughly equal to 200W, which was associated with 158.5 rpm feed rolls rotational speed, 800 rpm rotational speed of the cutting cylinder, and helix angle of zero. Contrarily, minimum power requirements for chopping alfalfa was 114W which was related to 158.5 rpm feed rolls rotational speed, 500 rpm rotational speed of the cutting cylinder, and 20º helix angle. Optimizing test results showed that the most suitable values for the feed rolls rotational speed, rotational speed of the cutting cylinder, and helix angle were 150 rpm, 677 rpm, and 9.22º, respectively, provided that power requirements and particle size are minimized and device capacity is maximized.

Keywords

Subjects

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Journal of Agricultural Science and Technology
Volume 20, Issue 5
July and August 2018
Pages 923-938