Diamond Grinding Wheel Used for Double Face Grinding of Alumina Ceramic

Ceramic materials are widely used in tools, automotive, aerospace, electronics, communications (fiber), medical and other industries. The market demand for ceramic materials is continuing to rise. The only obstacle is the processing cost. Sometimes processing costs account for 80%-90% of the total manufacturing costs. In order to obtain good surface roughness, ideal non-destructive surfaces and sub-surface layers, the machining of ceramic workpieces requires careful design and implementation of the grinding process to increase production efficiency, surface layer accuracy, finish and surface quality. Double face grinding is one of the most effective methods for finishing flat end faces. The main purpose is to achieve high removal rates and avoid surfaces or tissue damage to meet fine quality requirements. However, high drive power, large noise, and rapid passivation of the grinding wheel and clogging of the air holes inhibit the application of the double face grinding.

Unlike conventional grinding methods, single-end grinding and double-face grinding rely on large-area contact of the workpiece with the grinding wheel to remove the workpiece material at relatively low cutting speeds. During double-face grinding process, multiple workpieces run simultaneously between two grinding wheels horizontally placed , and the ground workpiece is placed in the opening of a specially designed and machined planetary wheel. In addition, three or more planet wheels continue planetary motion around the rotating central axis and the fixed outer ring. Therefore, a unique cycloidal trajectory is formed between the workpiece and the grinding wheel. Carefully calculated by the kinematic parameters, the workpiece is placed eccentrically in the planet gear, which avoids the wear ring of the grinding wheel. A smoother surface and a higher flatness can be obtained by selecting the type of track. Moreover, roughing and finishing can be achieved by controlling the rotational speed of the grinding wheel and the central shaft. The running speed of the workpiece changes alternately make the surface grain more uniform. The analysis results show that the influence of the grinding wheel speed on the surface roughness is significant, while the planetary wheel speed and pressure have no effect. In addition, processing time has a significant effect on the final surface roughness.

It’ll be better to divide into two stages for the double-face grinding process of alumina ceramics ground by vitrified bond diamond grinding wheel, namely short-time wet grinding roughing and several minutes of dry grinding finishing. The length of each stage depends on the workpiece material, the remaining amount and pressure, etc. High grinding wheel speed, low planetary speed, and high workpiece pressure will benefit for improving the grinding efficiency. Better surface roughness will be obtained with high surface speed and short grinding time.