Laboratory investigation on rotary impact cutter blade parameters for multistep cutting of Paddy straw

The present study focused on the laboratory evaluation and optimization of the chopping unit of straw chopper cum mixture machine for paddy straw management. During the study a laboratory setup was developed for simulating the cutting process of counter-rotating blades of a chopper for cutting of paddy straw. The effect of operational parameters i.e., blade type, rotational and forward speed of the machine, and crop parameters i.e. days after harvesting (DAH) on the power requirement was observed. The response surface methodology was used to develop a statistical model to predict the torque requirement for chopping straw by front attachment of the rotary tiller. The developed model was optimized in order to minimize power required during chopping operation. The results of study showed that the cutting torque was significantly (p≤0.05) affected by the rotational speed, forward speed and DAH of the paddy straw. A straw management system (SMS) serrated blade operating at rotational and forward speed of 900 rev. min⁻¹ and 1 km.h⁻¹ respectively with average cutting torque of 3.8 N-m was found to be optimal for cutting the paddy straw. The paddy straw chopping performed after 1–2 DAH requires minimum power. Hence, it was concluded that the optimized chopping system can be effectively used as cutting unit in rice straw incorporator.