Wear assessment of microcrystalline and electrofused aluminum oxide grinding wheels by multi-sensor monitoring technique

Combining the manufacturing processes with a sophisticated monitoring system is becoming more frequent in industry, following the trend in ‘smart manufacturing’. Multi-sensor monitoring techniques can enhance the efficiency and precision of the manufacturing process. Although many studies have been focused on the grinding process, we are still a long way from a complete understanding, which represents a challenge to the scientific community. The aim of this research was investigate the wear behavior of microcrystalline aluminum oxide grinding wheels, in comparison with a conventional electrofused aluminum oxide grinding wheel, through acoustic emission (AE) monitoring and the use of force transducers. The difference between the two cases is that in the manufacture of microcrystalline aluminum oxide grinding wheels microcrystalline abrasive grains are added to the composition (representing 45 %). A specific experimental rig was assembled for the measurement of the grinding cutting force and AE during the external cylindrical plunge grinding process. Two specific material removal rates were selected for the grinding of nodular cast iron GGG70 workpieces. The experimental rig allows the radial grinding wheel wear to be determined employing an AE-based contact recognition procedure. The wear behavior of the grinding wheel is evaluated by correlating the ground workpiece surface roughness measurements with the post-process analysis of both the grinding force components and AE signals. The results show that the wear behavior of the grinding wheels was dependent on the specific material removal rate used and was characterized by micro and macro-wear mechanisms. It was found through the surface roughness measurements and process characteristics that the addition of microcrystalline aluminum oxide grains has a significant influence on the wear behavior of the grinding wheel. Specifically, the microcrystalline grinding wheel presented lower magnitudes of radial wear when compared to the electrofused grinding wheel. The proposed monitoring method can be widely used to evaluate the wear of grinding wheels during the grinding process.