Improving surface integrity and economics of grinding by optimum coolant application, with consideration of abrasive tool and process regime

Abstract

As compared to machining, the chip thickness in grinding is small and the specific grinding energy is generally much higher than the specific cutting energy in machining. With such small chip thickness values, a lot of heat is created by non-chip removal interactions, such as ploughing and rubbing. These interactions occur between the chip and grain, chip and bond, and the chip and the work. Identification and manipulation of these interactions can allow the engineer to minimize the thermal limitation, improve surface finish, increase wheel life, etc. This paper discusses the thermal energy partitioning that occurs with different modes of grinding, and guides the reader towards processes with a lower specific energy and more desirable energy partitioning with respect to the energy that enters the final workpiece surface. The high efficiency deep grinding regime, is compared to creep-feed and shallow-cut grinding. The paper also looks at the cooling effect of grinding fluids and how they can be applied more effectively to cool and lubricate the workpiece surface. Best practices will be presented, based on analytical models and field experience. Flowrate and pressure models are used to optimize the main fluid jet that is applied to the grinding process. The heat transfer characteristics of superabrasive wheels, as compared to conventional abrasives, will also be presented and discussed. Finally, a case study is presented, that clearly shows the economic and technological advantages of coherent-jet nozzles over a more conventional approach.