What is the quantitative relationship between the particle size distribution of fiber discs (such as P80 to P1200) and the surface roughness of the processed surface?

There's a close quantitative connection between the particle size distribution of fiber grinding discs and the surface roughness of the processed surface. To put it simply, the coarser the particle size of the grinding disc is, the greater the surface roughness of the processed surface usually is. On the contrary, the finer the particle size, the smaller the surface roughness of the processed surface will be.

Coarse particle size (like P80): The abrasive grains on the grinding disc are larger, and they have strong cutting ability. But the scratches they leave are also bigger, so the surface roughness after processing will be relatively high. This particle size is good for rough grinding and can quickly remove a lot of material from the workpiece surface.

Fine particle size (like P1200): The abrasive grains on the grinding disc are smaller, and their cutting ability is relatively weak. But the scratches they leave are extremely small, so the surface roughness after processing will be very low. This particle size is suitable for fine grinding or polishing and can get a very smooth surface.

It should be noted:

It's not that the finer the particle size, the better. Although fine particle size can get a lower surface roughness, the grinding efficiency will go down, and the grinding disc itself is also easy to get clogged and worn. So, in real applications, the right particle size should be chosen based on the requirements of the workpiece and the production efficiency.

The relationship between particle size and grinding efficiency: Coarse particle size grinding discs have high grinding efficiency but large surface roughness. Fine particle size grinding discs have low grinding efficiency but small surface roughness. So, in the processing, it might be necessary to first use a coarse particle size grinding disc for rough grinding and then a fine particle size grinding disc for fine grinding to get both high efficiency and high quality processing results.

If you need to process a workpiece that doesn't have a high requirement for surface roughness, you can choose a P80 or coarser particle size grinding disc for fast grinding.

If you need to process a workpiece that requires a very smooth surface, like a mirror-like surface, then you need to choose a P1200 or finer particle size grinding disc for fine grinding and polishing.