Tooth surface-finishing method using the plasticity material was developed to improve the production efficiency and obtain the high surface durability of automotive power transmission gears. In the plasticity material, the volcanic-ashes, oil clay and mineral oil were mixed together. First, the test gear tooth was finished by plasticity material which flowed on the tooth surface. Secondly, the surface of test gear tooth was investigated using a scanning electron microscopy and a surface texture measuring instrument. From these experiments, the following results are obtained: By applying the designed tooth surface-finishing method to the shaved and case-carburized gear tooth, the mark of the shaving almost disappears. The asperity on the tooth surface becomes smooth. The absolute value of surface roughness decreases with the increase of the operating distance. Therefore, it is found that the tooth surface-finishing method have advantageous process from the viewpoint of resource saving, energy saving and environmental protection.
