Monitoring of the condition of diamond grinding wheels using acoustic emission technique

The grinding of hard materials depends mainly on the condition of the grinding wheel. A blunt wheel leads to contact with the workpiece resulting in an increase in the grinding forces, which affects the surface integrity and strength of the final product. An imprint of the profile of the grinding wheel was the method used in this work to measure the surface condition of the wheel. This was carried out by taking one grinding pass on mild steel specimens and measuring their roughness. Different levels of truing and grinding wheel speed ratios and directions were investigated for different bond types and grit sizes of diamond grinding wheels. An acoustic emission sensor with a high frequency sampling of 1.25 MHz was attached to the mild steel specimens to monitor the wheel condition. The raw AE signals generated from the grinding wheel/specimen contact were then analysed using a fast Fourier transform. The AE spectral amplitude of different grinding wheel bond types, grit sizes and their conditions represented by grinding wheel/truing speed ratios were then compared with the surface roughness (Ra) of the ground mild steel specimens.