How to measure the accuracy of rotary shaft of cradle type five axis machining center?

Release time:

2021-12-02

Precision measurement of rotary shaft of cradle type five-axis machining center

Traditionally, the calibration of the rotary axis of a machine tool requires an automatic precision turntable to be installed at its center of rotation in order to perform the rotary axis calibration. The rotary shaft rotation center (C.O.R.) of the cradle-type five-axis machining center is limited and has no coupling parts, resulting in the need for more complex brackets and alignment procedures to calibrate the axes, which may increase the difficulty of calibration of the machine.

Solution:

Measurement configuration: SJ6000 laser interferometer host angle lens group WR50 automatic precision turntable eccentric shaft accessory eccentric shaft measurement software.

The WR50 automatic precision turntable is installed on the-axis of the cradle-type five-axis machining center (it does not need to be installed at the center of rotation) and the test is performed. The eccentric shaft measurement software will synchronize linear and rotational movement and maintain the laser beam collimation during the entire test, which can significantly simplify the installation hardware setting requirements.

Working principle:

The working principle of eccentric shaft measurement is to use the synchronous movement of the linear axis and the rotary axis of the machine tool. As shown in the following figure, each revolution axis movement has a corresponding linear axis movement. Note that even with the same angular axis movement, the linear axis movement intervals will be different to ensure that the laser interferometer remains aligned with the automatic precision turntable.

Note:

Since one of the optical mirror sets is fixed to the moving linear axis, the detected angular axis data may also contain an error of the linear axis, such as the angular error shown below. For this reason, an additional, separate angle measurement should be performed simultaneously along the linear axis at the same stop position as was used during the initial synchronous movement, and then the two error files can be merged, eliminating the effect of the linear axis angle error and thus presenting the true rotation accuracy of the rotary axis.