Analysis of the electro discharge dressing (EDD) process of large-grit size cBN grinding wheels

The application of non-conventional truing/dressing (T/D) methods to the recovery of conductive-bond superabrasive wheels has been a matter of great interest in the last years, especially in the case of small-grit size wheels. However, when it comes to the dressing of large-grit size superabrasive wheels, applied in roughing operations, little information is available. The electro discharge dressing (EDD) process can be optimally applied in these cases. In this work a description of the particular mechanisms involved in bonding material removal in the EDD of large-grit size cBN wheels is presented. Indicators are defined in order to quantify the stability and efficiency of the process, and the influence of the main process variables (wheel speed, electrode size and electrical settings) is analyzed. Practical application shows that very important improvements in the grinding performance of the wheels can be obtained by maximizing grit protrusion while avoiding grain loss using this technique .