Zhao Haifeng，Guo Yan，Han Yuchen，Zhang Yu

Abstract:The measurement of form tolerance is an important basis for evaluating the accuracy of parts.In view of the shortcomings of the common testing methods for straightness，flatness and other geometric tolerance of parts，a highprecision photoelectric detector for geometric tolerance of laser plate target is designed.The typical three coordinate walking mechanism moves along the surface of the measured part，laser emission device installed on the Z axis of the emitting laser beam to four quadrant PSD synchronization board target.The signal is amplified and collected by circuit in realtime.The computer record and display the current test value.Compared with the existing measuring devices，the design can be used for online testing and rapid evaluation of straightness，flatness shape tolerances.