Seibu's unique stone lapping methods make optimal use of the characteristics of machine tools, lapping stones, and control systems; we have established our own unique stone lapping methods.
Our machine tools are built rigidly with minimal vibrations. Stones, with ultrafine abrasive diamond or CBN grains, are retained by rigid holders, and the stones are also rigid. The stones are oscillated (vibrated minutely) in parallel with workpieces under low pressure through the use of our uniquely developed air bearings.
Consequently, Seibu's unique stone lapping methods generate low heat, and produce profile accuracy as well as nano-level accuracy of finished surface roughness.
It has also been confirmed that Seibu's unique stone lapping methods produce negative residual stress on the surface layers of workpieces. Seibu will continue research, development, and investigation on physical properties, in addition to study of profile accuracy, to verify the issues relating to residual stress.
In the case of using an oscillation guide which uses air bearings, the grinding ratio of a lapping stone having a lower level of hardness can increase by 2 to 3 times compared to a guide using a rolling element.
With the above results, the oscillation movement becomes a figure-eight movement in relation to the generating line, leading to a smaller encircling angle and reduced form-adjusting capability conforming to the prior process.