Analysis of blockage and wrapping by leaves in the cutting mechanism of a sugarcane leaf shredder

Abstract

Sugarcane leaves are long and have high flexibility. A machine to pick-up, shred and return sugar cane leaves to the field has been designed. It consists of a roller which picks up leaves and feeds them into a cutting mechanism where they are then shredded. The working width of the cutting mechanism of the machine is less than the feeding width of sugarcane leaves and this can easily cause blockage and wrapping of the cutting mechanism. To address this issue, the blade roller of the machine was improved by adding anti-wrapping pipes and using bent blades. Based on a theoretical analysis of sugarcane leaves in different feeding states, it was shown that the structural parameters of the blade roller, wrapping length of sugarcane leaf and forward speed of machine were the key factors influencing blockage and wrapping. By simulating the cutting process of sugarcane leaves using LS-DYNA in two feeding states, the average displacement of sugarcane leaf elements in contact with the anti-wrapping pipes and bent blades was obtained. The simulation results showed that the average displacements of sugarcane leaf elements under two feeding states were greater when the blade roller had anti-wrapping pipes and bent blades, which indicated that the improved blade roller was more conducive to cutting sugarcane leaves. High-speed photography of the cutting process showed that cutting sugarcane leaves in the transverse feeding state was an improvement and only a small amount of leaves in the longitudinal feeding state were wrapped around, and adhered to the rotary blades and anti-wrapping pipes. However, there was little wrapping of the bent blades. The experiment showed that the average cutting rate and its standard deviation were 91.68% and 1.58% respectively, and the average wrapping rate and its standard deviation were 1.13% and 0.37%, respectively. • Cutting mechanism with bent blades and anti-wrapping pipes developed. • Three feeding states were identified for sugarcane leaves in cutting mechanism. • Bent blade and anti-wrapping pipe reduce blockage and wrapping in cutting mechanism. • Improved cutting mechanism enhance the performance of sugarcane leaf shredder.