Design and near net shape casting of an AA6061 automotive rocker arm with electrochemical performance evaluation

Abstract

The increasing demand for sustainable and cost-effective automotive spare-part production has encouraged the adoption of near-net-shape manufacturing techniques. This study presents the CAD modelling, finite element analysis, floor-mould casting, and electrochemical evaluation of an internal combustion engine rocker arm produced from Aluminium Alloy 6061. The rocker arm geometry was developed from OEM-derived field measurements and analysed under a representative static valve load of 500 N. The FEA results showed a maximum von Mises stress of 96.3 MPa at the neck region and a minimum factor of safety of 2.87, indicating that the component remained within the elastic design limit under the assumed loading condition. The component was fabricated by sand casting with minimal machining, showing the feasibility of near-net-shape production. Electrochemical testing in 3.5 wt% NaCl solution revealed that the cast AA6061 sample had a lower corrosion current density than the OEM specimen and a substantially higher polarization resistance. These results suggest that locally produced NNS-cast AA6061 rocker arms can provide acceptable structural performance under the investigated static loading condition and higher electrochemical corrosion resistance under the investigated laboratory chloride exposure condition, supporting decentralized production of lightweight automotive spare parts in developing economies. This implies that NNS casting is a highly feasible, resource-efficient, and structurally viable process for producing lightweight automotive spare parts.