Design of a Dual Operated Cassava Chipper

Abstract

Size reduction of agricultural products is an essential requirement for their processing and transportation. This research designed and fabricated a manually operated and motorised cassava chipping machine, which is adaptable to the local farmers at the cottage level. The design was carried out by empirically computing the threshold force required for cutting the cassava tubers, with a prior knowledge of the length (350 mm) and thickness (1.5 mm) of the cutting blades as influencing indexes. Also, the capacity of the machine was evaluated using six different cutting forces above and below the cutting threshold force (68.99 N). The results show that the cutting force increased exponentially with the length and diameter of the tuber. Also, less force was required to chip cassava tuber with longer length and shorter diameter probably due to the presence of inner and central crack defects, which is capable of forming easy crack initiation points with the slightest blade effort . The size of the electric motor required was a single phase 1 hp (4500 rpm), which is capable of powering the machine to an approximate capacity of 225 kg/h and comparable to the required human effort. The machine was also found effective in chipping cassava tuber to average size of 30 mm.