Measuring coaxiality and perpendicularity of the axis to end plane using optical method

In this paper a novel method of measuring coaxiality and perpendicularity using laser alignment, diffraction imaging and CCD image detecting is proposed. In this method, we use a laser diode fiber alignment beam as the datum reference of straightness, deviation of the center of the hole from this datum, coaxiality, can be detected by a CCD camera. By rotating a penta-prism that makes this alignment beam bend a right angle a scanning datum plane is generated which can be used to detect the perpendicularity of the axis to an end plane. In the paper the factors that affect the accuracy of the system are analyzed. The experiment result shows that the measurement accuracy of the system is 3+2.3×10^-6.