How areroller bearingsmade

Oh, that! The balls are being ground inside grooved metal disks at a tremendously high pressure. That’s why the noise is so loud!

How arebearingsmade

That’s because the balls are inside a retort furnace heated to a very high temperature of 800°C or more. Cooling the balls quickly from a high temperature changes the structure of the steel, making it harder. This process is called quenching. However, since the balls are still brittle, they are heated again to a high temperature to further strengthen them. This process is called tempering.

In addition to removing parts decarburized in the heat treatment, this process adjusts dimensional precision and finishes the balls to the stipulated dimensional difference.

You are a clever boy, Kyusuke! The process here uses an ever finer grindstone than the one used in the first lapping process. Processing the balls over and over again produces more spherical, shiny balls!

The dimensional precision of the balls is further improved and they are finished to the specified dimensional difference.

How aremetalballs made

That’s right! Inspecting all of the balls and all of their surfaces ensures that no flawed balls are distributed. From the users’ perspective, inspecting all of the products is assuring, isn’t it? These careful inspections are another reason why Amatsuji products are know as the “World’s No. 1.”

Each box weights 4 kg. This has been set at the weight that a person can lift with one hand. Cardboard boxes weight 20 kg in consideration of the weight a person can safely carry. This consideration for safety after products have been shipped is typical of AKS.

That’s very observant of you. In the previous process, the balls were ground inside metal disks, but here grindstone disks are used. Using a grindstone increases the dimensional precision of the finish. Changing the grinding disk also changes the dimensional precision of the balls.

Bearingmanufacturing process PDF

All of the finished steel balls and all of their surfaces are visually inspected automatically. These visual inspections ensure that the balls supplied to customers have no flaws.

In addition to increasing the balls’ dimensional precision to grade level, this process gives the surface of the balls a smooth, glass-like finish.

It depends on the size of the ball, but the fastest machines can produce around 1,000 balls in one minute. Incidentally, the balls have only been compressed, and so they still have a protruding band around the middle, like a belt. This is removed in the next process.

Even though grinding improves the dimensional precision, this is still a far cry from the precision required in the product. Processing the balls using grindstone with a finer granularity than before increases the precision of the balls and stabilizes product quality.