This article explores the possibility of improving the design of CANTAS, by focusing on the failure analysis and the design optimisation of its sickle blade. The sickle blade material was replaced with 6262-T8 aluminium alloy. An analysis to inspect the sickle’s mechanical strength against 300 N of cutting force was simulated using the finite element method (FEM) software. The total stress experienced by the new design (i.e., 1204 MPa) exceeded the material’s ultimate tensile strength of 390 MPa; therefore, would break due to mechanical failure. The dimension of the weak point on the sickle was then increased to 25%. The improved sickle design only experienced 314 MPa of stress and did not exceed its ultimate tensile strength. The design was further optimised to reduce its weight. A reduction of 14% was achieved compared to the previous improved design and 69.7% compared to the original spring steel sickle with only 352 MPa of stress experienced. It also can withstand any directional impact force in drop test simulation. The aluminium alloy sickle is also48% cheaper than spring steel sickle. However, a cost per tonne of productivity calculation shows that the performance of both sickle materials is very much the same.