The choice of high quality grinding disc
abrasive grain size mainly considers the requirements of grinding efficiency and workpiece surface roughness. Generally, it can be selected according to the following points.
1. The workpiece processing precision is high, and when the surface roughness value is low, the abrasive material with fine abrasive grain size should be selected. The smaller the abrasive, the more abrasives are involved in the cutting, the smaller the abrasive cutting marks remaining on the surface of the workpiece, and the lower the surface roughness value. However, the choice of abrasive particle size must also be considered in conjunction with the grinding conditions employed. If the grinding amount used is small and the depressed grinding disc in stock
is finely finished, the lower the surface roughness of the workpiece can be obtained by using a coarser abrasive grain size.
2. When the contact area between the abrasive tool and the workpiece surface is relatively large, or the grinding depth is also large, the coarse-grained abrasive should be selected. The coarse-grained abrasive and the surface of the workpiece have less friction and less heat. Therefore, when grinding the end face of the high-quality grinding disc, the selected abrasive grain size can be coarser than when grinding the periphery of the depressed grinding disc in stock.
Usually. The grinding of the flat grinding adopts the high quality grinding disc of 36#~46#, and the surface roughness Ra of the workpiece can reach 0.8~0.4μm. If the depressed grinding disc in stock speed vs. is reduced and the grinding depth ap is reduced, the surface roughness Ra of the workpiece can reach 0.4μm~0.2μm. When grinding, the grinding is performed with the abrasive of 150#~240# grain size, and the surface roughness value of the workpiece is Ra. Or lower. In the case of mirror grinding, a graphite high quality grinding disc of a resin binder of a fine powder W10 to W7 particle size is used.
3. When rough grinding, the machining allowance and the grinding depth used are relatively large, and the abrasive grain size should be coarser than that of fine grinding, so as to improve production efficiency.
4. For the cutting and trenching process, abrasives with coarse grain size, loose structure, and high hardness should be used.