Atividade

Lapping

Finished steel balls, including middle carbon steel ball.The last step in the process is to lap the balls. Lapping is a superfinishing process that improves the surface finish or geometry and removes small amounts of material so that the balls attain the tight, required tolerances.

The balls are rolled between two hardened steel plates, with one fixed and one rotating at a low speed. The balls are now perfectly round and have a mirror-like finish.

Washing and sizing

Now that the manufacturing process is complete, they are washed to remove any leftover residue. Lastly, the clean balls are inspected for scratches and sized. Even though the balls all have the same nominal outside diameter, small variances still occur. The ball grade defines the geometric tolerances of the bearing. The lower the grade number, the tighter the tolerances. The number of the grade is related to the sphericity and diameter variation of the balls. The tolerances are extremely tight and the variation between balls is quite small.