Static Error Measurement For Rotary Axes Of Five-axis CNC Machine Tools Based On Touch-trigger Probe

The machine tool is the machine that manufactures other machines.The machine tool is the working machine.The precision of the machine tool is the basis for the precision of other machines,which affects the improvement of the industrial level to a certain extent.The five-axis CNC machine tool has a large inventory and is widely used in fields where high precision is required.The research and application of the linear axis error of the five-axis CNC machine tool has been mature.Now the important source of the error of the five-axis CNC machine tool is the error of the rotating shaft.Therefore,this paper focuses on the modeling and measurement of the static geometric error of the rotating shaft of the five-axis CNC machine tool.According to the arrangement form of the five-axis CNC machine tool and the motion relationship of each axis,the kinematics model of the machine tool is established by using the homogeneous coordinate transformation matrix.The static geometric error of the rotating axis is preset in the model.The static geometric error of the rotating axis is identified according to the proposed identification algorithm.The error of the preset error and the identification error is compared to verify the effectiveness of the identification algorithm.The five-axis machine tool is divided into two types: the rotary axis on the workpiece side and the rotary axis on the tool side.The identification algorithm is designed according to its characteristics to identify the static geometric error of the rotary axis.The static geometric errors of the rotatry axis have different effects on the actual output coordinate values.The relationship between the error of the rotating shaft and the actual coordinate value is established.Then the errors are integrated and the static geometric errors of the rotating shaft are obtained according to the geometric relationship.In the measurement,the touch probe to be used is the standard ball.The probe is a high-precision measuring instrument with simple operation,high precision and wide application.The standard ball is a high-precision sphere with excellent geometric properties.The standard ball is free to measure position,making it easy to implement the measurement position required by the identification algorithm.In the process of measuring the standard ball with the touch probe,the probe and the standard ball are highprecision instruments,and interference should be avoided to prevent damage to the instrument.The safety measurement area is also proposed based on the geometric relationship between the measurement path and the instrument designed by the identification algorithm.The static geometric error of the rotating axis is preset in the model.The static geometric error of the rotating axis is identified according to the proposed identification algorithm.The error of the preset error and the identification error is compared to verify the effectiveness of the identification algorithm.Using the three-dimensional simulation software Vericut to add different rotation axis geometric errors to the five-axis CNC machine tool,the verification identification algorithm can safely,quickly and effectively identify the static geometric error of the rotary axes of different forms of five-axis machine tools.