Influence of Cutting Edge Shape on Residual Stresses of Cut Surface* (Effects of Nose Radius and Cutting Edge Roundness)

In order to obtain basic information on the improving the surface integrity of machined surfaces, the relationship between the residual stress of cut surfaces and the cutting edge shapes of cutting tools was examined. Dry facing on a lathe was performed with cutting tools that had various nose radiuses and cutting edge roundnesses. The residual stresses of the cut surfaces were measured by X-ray diffraction method. The results obtained are as follows. When the rake angle was about zero degrees, it found that the nose radius barely affected the residual stresses of the cut surfaces. However, when the negative rake angle was large, the nose radius significantly affected the residual stress. The residual stresses of the cut surfaces shifted compressive side when there was an increase in cutting edge roundness. The residual stress of a cut surface is kept in a high compressive state even though the cutting force decreases greatly due to grinding removing the rake side part of the cutting edge roundness.