Effective Cooling and Lubrication

The humble coolant nozzle can have a greater impact on the grinding process than you think. In this feature, Dr John A. Webster examines the role coolant plays in the search for a quality surface finish and micron accuracy. Nozzles are an established way of supplying coolant into a grinding process to control the part temperature, keep the wheel clean and open for chip flow, allow the extreme pressure additives in the coolant to do their job, and flush the chips away from the cutting area and into the filter system. Plastic modular nozzles work well at low pressure (2 bar) but can move out of position at the higher pressures that give better grinding. They are easy to aim, but need to be placed close due to the dispersed jet nozzle geometry. Rigid metal tubes—such as copper and steel—are stiffer, but also give dispersed jets that entrain air into the coolant unless the end is accurately swaged or a nozzle tip attached to the end. Aiming and re-aiming them requires frequent bending that ultimately leads to their fracture.