Analytical and experimental investigation of coolant velocity in high speed grinding

Use of water-base coolant is a pre-requisite in an high speed grinding process to avoid thermal damage and to achieve better surface integrity as well as higher grinding ratio. However, the presence of hazardous chemical additives in the coolant causes environmental problems. As a result, stringent government legislation is being practiced for the coolant use and disposal, which consumes 7–17% of the total machining cost. This paper reports the coolant flux minimization through controlled jet impingement so as to prolong the coolant replenishment cycle. Control of coolant flux was achieved through development of a “metered quantity coolant” (MQC) nozzle which supplies the required amount of coolant to the grinding zone. Also, this investigation has shown that coolant velocity has a significant influence on the high speed grinding performance. When the coolant velocity is inadequate, coolant could not penetrate into the grinding zone. The increase in coolant velocity was realized with reduction in nozzle opening area and does not use a large quantity of coolant. This is of significance to reduce environmental pollution and machining costs through extended coolant replenishment period.