Grinding is a common method of semi-finishing and finishing and the grinding wheel is a common cutting tool. The basic characteristics of grinding are as follows:
1. High cutting speed in grinding leads to high grinding temperature. The speed of ordinary cylindrical grinding is about 35m/s, while the speed of high-speed grinding is generally greater than 50m/s. 80% ~ 90% of the cutting heat generated by grinding is passed into the workpiece (10% ~ 15% is passed into the grinding wheel, 1% ~ 10% is taken away by the grinding chip).Plus, the poor thermal conductivity of the grinding wheel is easy to cause burns and microcracks on the surface of workpiece. Therefore, a large amount of cutting fluid should be used to reduce the grinding temperature.
2, High machining accuracy and small surface roughness can be obtained by grinding. And the grinding wheel can not only be used for finishing, but also roughing grinding and heavy duty grinding.
3. High thrust grinding force. Due to the big negative rake angle of the abrasive grain and the cutting edge roundness, the thrust grinding force is bigger than the tangential grinding force which resulting in a larger contact width between the grinding wheel and the workpiece. That will lead to the elastic deformation of workpiece, fixture and machine tool, which will also affect the machining accuracy. Therefore, when machining the workpiece with poor rigidity (such as slender shaft), corresponding measures should be taken to prevent deformation of the workpiece.
4, The grinding wheel has self-sharpness. In the grinding process, the abrasive grains are broken to produce new sharp edges and corners, and the abrasive grains will fall off form grinding wheel to reveal new sharp edges, which can partially restore the cutting ability of the grinding wheel. This phenomenon is called the self-sharpening effect of the grinding wheel, which is conducive to grinding.
