Cooling by sub-zero cold air jet in the grinding of a cylindrical component

This paper investigates the cooling effect when using an air jet at sub-zero temperature of ?15 °C in the plunge grinding of a cylindrical component made of high strength steel EN 26. A three-dimensional finite element heat transfer model with a moving heat source was developed to reveal the complexity of the heat transfer mechanism involved. It was found that the use of cold air does not significantly reduce the temperature rise in grinding and that the cooling effectiveness is mainly limited by the following facts: (a) the air jet is difficult to penetrate into the grinding zone, (b) the heat transfer coefficient provided by an air jet is small and (c) cooling is limited by the time which the rotating workpiece surface can be exposed to the jet impingement. The study also showed that the present modelling method can be used as a first tool to assess the feasibility of a new cooling medium for grinding operations.