Aluminium (Al) based metal matrix composites (MMC) have many potential engineering applications. There has been a critical need for casting of cost-effective MMC. Not much work hitherto been reported for casting of Al based MMC with vacuum moulding. An approach to macro-model the micro hardness and dimensional accuracy for casting of MMC of Al and its alloys have been proposed and applied. Relationship between micro hardness, dimensional accuracy and other parameter has been deduced by using Taguchi’s technique L9 orthogonal array (OA). Results indicate that the hardness of MMC developed depends significantly on the component volume, pouring temperature and composition. The comparison with experimental results will also serve as future validation of the model.