Selection on Particle Size of Superhard Materials

The selection on particle size of superhard materials is generally based on the surface roughness and machining efficiency of machined workpieces. The selection principles of diamond abrasives and cubic boron nitride abrasives are basically same. If we want to get the same surface roughness, the particle size of abrasives should be finer about 1 ~ 2 size, compared with common abrasives; At the same time, on the premise of meeting the requirements of surface roughness, we should also consider high machining efficiency and satisfactory processing effect, so we should choose coarser particle size as far as possible.

The selection on particle size of superhard abrasives products should also consider the strong and weak influence of bonding ability. For a certain amount of binder, the grinding removal of workpiece materials will increase along with the increase of particle size, and the grinding ratio will also increase. But if the particle size of abrasive grains is too thick, it will sharply increase the abrasive wear and the grinding ratio will also fall instead. It is particularly significant for resin binder with weak bond capacity. On the other hand, if the particle size is fairly fine, the grinding will be reduced and easy to jam the working face of abrasives products,  which will make the temperature risen and cause non-working loss.

For resin bond superhard abrasives products, the overheating working surface will cause thermal decomposition of bond, prompting abrasive wear increased dramatically. Therefore, there is a best particle size range to determine the bond abrasives products. In this range, the grinding efficiency and wear are the best. Usually, the resin bond superhard abrasives products choose the sizes within #100; Ceramic abrasives products choose the sizes within 100# ~ 180#; Metal bond abrasives products choose the sizes within the scope of 80# ~ 240#.

The abrasive particle size selection of different grinding process should be based on machining conditions and requirements and the best particle size range. Recommended particle sizes are as follows: Coarse grinding #80 ~ #120; Fine grinding #120 ~ #180; Grinding and polishing W40 ~ W1.

For the grinding with special requirements, we can choose some abrasives products  with coarser or finer particle sizes. For example, the form grinding can choose finer abrasive grain sizes than the general particle size in order to improve the formability.