Temperature control in CBN grinding

Abstract

The main advantage of CBN grinding wheels is the long wheel life owing to the hardness of the CBN abrasive. Recent research has confirmed another advantage of CBN, which is cooler grinding. The new research allows the temperature in grinding to be predicted based on experimentally validated CBN thermal properties. This work also provides for in-process prevention of thermal damage in grinding. A well-documented feature of CBN grinding is the reduced risk of thermal damage to the workpiece. This advantage can allow a marked increase in removal rate whilst maintaining surface quality of the component compared to grinding with conventional abrasives such as aluminium oxide. The reduced risk of thermal damage in CBN grinding is sometimes attributed to the lower grinding specific energies. While lower specific energies when achieved are an advantage, this explanation ignores a fundamental advantage of the CBN abrasive. The experimental investigation has shown that a major advantage of CBN grinding is that a substantially lower proportion of the total grinding energy enters the workpiece compared to grinding with alumina wheels. The results further indicate that the effective thermal conductivity of CBN grains is considerably lower than its reported theoretical value of 1300 W(mK)⁻¹.