Development of non-contact automatic thread measuring instrument

The principle and implementing method of non-contact thread parameter inspection based on laser triangular measurement principle were presented. An inspection instrument was designed and produced, which included axial displacement measurement module, transverse displacement measurement module and a module to deal with, control and assess the data in the upper system. The algorithm for inspecting the main parameters of the thread was given. The inspection and estimate of the thread contour curve were completed by using laser gauge to measure the dimension of the thread contour curve in the transverse section, and using raster to measure the axial displacement of the precision worktable under the thread test criterion. The inspection resolution of the equipment is 1.5 μm, which can meet most requests from customers. This instrument can solve the distortion problem caused by contact measurement, control the manufacturing quality of the thread, and improve the inspection precision and efficiency.