Grinding wheel grit refers to the size of abrasive particles, which is just one unit; particle size refers to the actual diameter of small particles. Particle size is divided into two categories: abrasive grains and micron powders.
Grinding wheel size is expressed in terms of the number of holes per inch of screen through which the abrasive grains pass.
1. Grit classification
Abrasive grade 2000 - 40μm [micron]
Micron grade 40 - 0.5μm [micron]
Abrasives with a particle size greater than 40 μm are called abrasive grains. Classified by screening method, the particle size number is expressed as the number of holes in the inch length of the screen through which the abrasive particles pass. For example, 60# abrasive grains are just the right size to pass through a sieve with 60 holes per inch. Abrasives with a particle size less than 40 μm are called micropowder. The microscopic measurement method is used for grading. W and the number after it are used to represent the particle size number. The value after W represents the actual size of the micropowder. For example, W20 indicates that the actual size of the micropowder is 20 μm.
2. Grit range
Rough grinding 80#-120#; Semi-fine grinding 120#-180#; Fine grinding 180#-W40; Polishing W40-W1
Rough grinding (high efficiency, low surface finish)...24#, 30#...180#, 240#, W40... (good finish, low efficiency) Polishing
3. How to choose grinding wheel grit
It mainly depends on what kind of surface finish and dimensional accuracy the workpiece to be ground should achieve, what kind of grinding efficiency should be achieved and the hardness of the object being ground.
The choice of grinding wheel grain size affects the surface finish and grinding efficiency of the workpiece; generally as long as the surface finish of the workpiece is met, we can choose a coarser grain size to save time.