Prediction of Machining Accuracy of 5-Axis Machine Tools with Kinematic Errors

Abstract

Kinematic errors due to geometric inaccuracies in 5-axis machine tools cause deviations in tool positions and orientation from commanded values, which consequently affect geometric accuracy of the machined surface. The present research work studies the prediction of machining accuracy of a 5-axis machine tool with its kinematic errors. First, kinematic errors associated with linear and rotary axes of a 5-axis machine tool with tilting rotary table types, are identified by a DBB method. By using an error model of the machine tool, erroneous tool position and orientations are computed. Then, machining error with respect to the nominal geometry is predicted and evaluated. With the aim to improve the geometric accuracy of a machined surface, an error compensation for tool position and orientation is also presented. As an example, the machining of a tilted taper cone by using a straight end mill, as described in the standard NAS979, is considered in a case study to experimentally verify the prediction and the compensation of machining errors in 5-axis machining.