Angled and serrated blades reduce damage, force and energy for a harvester basecutter

Mechanical cane harvesters cut the cane at its base by way of an impact cut, using multiple blades mounted on a rotating disk. A knockdown roller bends the cane stalks prior to cutting by the basecutter, and feeding them into the feed train. Knockdown and basecutting are responsible for damage and losses of the stalk, and disturbance of the stool with possible damage to the root systems. Another major problem for the mills is the dirt incorporated in the cane supply by the action of the basecutter. A series of cutting tests using serrated blades has been carried out at the Sugar Research Institute in Mackay, Queensland. An experiment was conducted using a factorial design with two types of blades (backward and forward), five angles and four edge micro shapes plus a standard blade and four repetitions for each test. Only two cutting speeds were used, equivalent to a disk speed of 450 and 600 r/min. Backward and forward blades show significant difference for energy in all parameters investigated (cutting speed, type of serration, and angle). Damage and forces were different across cutting speed and types of serration. The variation of angle shows differences in damage for forward blade and force for backward blade. Intuitively, the main problem with serrated edges for basecutter blades, used right at the soil level, is one of rapid wear. To avoid this problem, it is planned to use a serration with long pitch and small tilt angle facing down that can be sharpened by the soil surface. Two field tests have been used to assess the effectiveness of serrated blades and forward angled blades fitted in a dished basecutter. Angled and serrated basecutter blades can represent a practical and economical solution for reducing cutting forces, energies, stool damage and dirt entry.