KM bearing | follow the small series to understand the bearing ring superfinishing process
Superfinishing machining can be divided into three stages: cutting stage, half cutting stage and finishing stage.
(1) Cutting stage
The grinding stone surface and rough raceway surface convex peak contact, because the contact area is small, the pressure on the unit area is larger, under the action of a certain pressure, the grindstone first by the workpiece "anti-cutting" action, so that the grindstone surface part of the grinding grain off and broken, revealing some new sharp grinding grain and edge. At the same time, the convex peak of the workpiece surface is rapidly cut, and the convex peak and grinding deterioration layer are removed by cutting and anti-cutting. This stage is called the cutting stage, in which most of the metal is removed.
(2) Half cutting stage
As the processing continues, the surface of the workpiece is gradually ground down. At this time, the contact area between the grinding stone and the workpiece surface increases, the pressure on the unit area decreases, the cutting depth decreases, the cutting ability decreases. At the same time, the pores on the surface of the millstone are blocked, and the millstone is in a semi-cutting state. This stage is called half cutting stage, in the half cutting stage workpiece surface cutting marks become shallower, and appear darker luster.
(3) Polishing stage
This is the final stage of superfinishing. As the surface of the workpiece is gradually polished, the contact area between the grindstone and the workpiece surface is further increased, and, the grindstone and the workpiece surface is gradually separated by the lubricating oil film, the pressure on the unit area is very small, is not enough to make the grindstone self-sharpening, cutting effect is reduced, and finally tends to automatically stop cutting. This stage is called photonic stage. Working surface of smooth finishing stage has no cutting marks and appears overall luster.