To promote sustainable manufacturing process, the use of coolant during machining should be controlled in order to reduce environmental pollution and health problems. Furthermore, the amount of coolant used in the conventional flooded technique is quite huge that caused an increment in production cost. It is believe that the amount of the coolant supply during machining process need to be reduced and controlled in order to solve the problems. The aim of this study is to investigate the effectiveness and the performance of a proposed automated coolant supply system with the use of PLC to control the amount of coolant supply through timing control in order to minimize the use of cutting fluid. The performance of the automated coolant system has been assessed based on surface roughness when machining Aluminium alloy and the results are compared to the one with conventional flooded coolant system. The experimental evidences show that surface roughness for 5 second on-off coolant supply is higher than conventional flooded cooling technique while the surface roughness for 10 second to 20 second on-off coolant supply is largely improved and much better than conventional flooded cooling technique. However, the roughness results for 25 second on-off coolant supply is slightly worse than 20 second on-off coolant supply but it still better than conventional flooded cooling technique. The results of this research work indicated that automated coolant supply system can replace the conventional flooded cooling technique in machining operation without any significant negative effect on the surface roughness result.