Geometric error modeling and tracing of heavy-duty vertical lathe based on virtual machined rotary surface

The machining error of heavy-duty vertical lathes is significantly affected by geometric errors. Thus, this paper investigates the measurement and modeling of heavy-duty vertical lathes for error tracing. Specifically, the heavy-duty vertical lathe geometric error is measured by a laser interferometer, its error value is identified, and the polynomial model of the error value is established using a polynomial high-order fitting method. After that, based on the multi-body system theory, the heavy-duty vertical lathe bed and cutting tool topology is created to describe the pose relationship of each component of the heavy-duty vertical lathe. Then, the geometric error model of the heavy-duty vertical lathe is established using a homogeneous transformation matrix, and the virtual machined rotary surface model is constructed by combining the cutting tool trajectory and the eccentric installation of the workpiece. Each geometric error is input into the virtual model to compare its effect on the machining error of the workpiece. Among the 19 errors traced, the X-direction positioning error of the horizontal slide, the X-direction straightness error of the vertical slide, the X-direction straightness error of the workbench spindle, the X-direction installation eccentricity error of the workpiece, the rotation angle error of the horizontal slide around the Y-axis, and the rotation angle error of the workbench spindle around the Y-axis are the key errors heavily impacting the machining error of the heavy-duty vertical lathe. According to the influence of each key error term, the mapping relationship between the error term and the machining error of the workpiece is established to complete the error tracing.

Automated summary

This paper investigates the measurement and modeling of heavy-duty vertical lathes for error tracing, and establishes the geometric error model of the lathe using a homogeneous transformation matrix. The key errors heavily impacting the machining error of the lathe are the X-direction positioning error of the horizontal slide, the X-direction straightness error of the vertical slide, the X-direction straightness error of the workbench spindle, the X-direction installation eccentricity error of the workpiece, the rotation angle error of the horizontal slide around the Y-axis, and the rotation angle error of the workbench spindle around the Y-axis. The mapping relationship between these key error terms and the machining error of the workpiece is established to complete the error tracing.