Non-contact method of thickness measurement for thin-walled rotary shell parts based on chromatic confocal sensor

In this paper, a non-contact method of thickness measurement for thin-walled rotary shell parts based on chromatic confocal sensor is presented. To obtain thickness, a flip method is applied to acquire surface profiles from both sides of the workpiece. The decentration and tilt errors of the workpiece are measured by a centering system consisting of a laser interferometer and a collimated tube. By establishing a unified reference coordinate system, the external and internal surface profiles are reconstructed and the thickness is calculated. A measurement experiment for a sapphire spherical shell workpiece was conducted on a four-axis measurement system and the result is 2.99341 mm. A wavelength-tuning interferometer and a dynamic interferometer were utilized to measure the sapphire spherical shell and an aluminum concave sphere and the results show in good agreement.

Automated summary

This paper presents a non-contact method of thickness measurement for thin-walled rotary shell parts based on a chromatic confocal sensor. The method involves using a flip method to obtain surface profiles from both sides of the workpiece, measuring the decentration and tilt errors of the workpiece using a centering system, establishing a unified reference coordinate system, reconstructing the external and internal surface profiles, and calculating the thickness. Experimental results show that the method can accurately measure the thickness of a sapphire spherical shell workpiece and is consistent with measurements of other materials.