Effect of Stem Diameter, Moisture Content and Cutting Speed on Cutting Force for Groundnut Harvesting.

To design,and develop harvesting machines, the most important optimized parameter is the cutting force.The study was conducted to investigate the effect of stem diameter, moisture content, and cutting speed on the cutting force required for cutting groundnut stalks. The cutting force was measured using the reciprocating cutter bar test rig. Experiments were carried out at three levels of moisture content (40 - 47, 47 – 53, and 53 – 60 %) (wet basis), three levels of crop stem diameter (15- 17, 17 – 19, and 19- 21 mm) and three levels of cutter bar speed (0.80 – 0.90, 0.90 – 1.00 and 1.00 – 1.10 ms-1). The cutting force required for cutting groundnut crop stem was calculated for all the treatments. It was observed that increase in stem diameter, the cutting force increased by 19.83 % and increase in moisture content and cutter bar speed,the cutting force decreased by 37.57 %, and 34.11 %, respectively. The required cutting force (100 - 120 N) and energy (1.5 - 2.0J) was minimum at the cutter bar speed of 1.00 - 1.10ms-1 for 53 – 60 % moisture content, 15 - 17 mm stem diameter and they were maximum at cutter bar speed of 0.80 – 0.90 ms-1 (140- 160 N and 2.5 – 3.0 J)for 40 – 47 % moisture content, 19 – 21 mm stem diameter. The results showed that the cutting force requirement was increased with an increase in stem diameter and decreased with an increase in moisture content and cutting speed.