SURFACE FINISH PRODUCED BY A VIBRATING TOOL DURING TURNING

Using an electro-hydraulic vibrator, a carbide lathe tool can be made to vibrate either in the horizontal or vertical direction at frequencies up to 125 c/s while cutting a mild steel workpiece. In the horizontal direction (parallel to the workpiece axis), provision is made for the synchronization of the tool vibration with the workpiece rotation so that the phase angle between the tool path on successive revolutions of the workpiece can be set at a number of known values. No synchronization is provided in the vertical direction. Tests are carried out for a number of cutting speeds and feeds with both horizontal and vertical vibration and the surface finish obtained is compared with that obtained using a static tool under the same conditions. Theoretical expressions for the CLA value of surface finish under dynamic and static conditions are developed, and using these, theoretical and practical values of surface finish are compared. Reasonable agreement between these values is found. As predicted by the theory, the surface finish produced by the vibrating tool is generally worse than in the static case, the only exception being at very low cutting speeds where the vibration appears to prevent the formation of a built-up edge and the consequent tearing of the workpiece surface. © 1969.