Design And Implementation Of Special Detection Software For Large Size Thread

Thread is widely used in mechanical engineering,aerospace and other fields.The precision of thread will affect its parts interchangeability,reliability,air tightness and other characteristics.There are many detection methods for thread,and the development is fast.But for the detection of large diameter(>l80mm)thread,the traditional detection method requires a full set of measuring gauges,and there are many problems,such as large quantity of gauges,heavy weight,high manufacturing cost and large labor intensity.In this paper,based on the research of thread measuring equipment at home and abroad,the non-contact triangle laser method is adopted to detect the thread,designs and develops a large-size thread detection system with coordinate machine as frame,rotating platform and laser displacement sensor as main components,and designs the corresponding special detection software of large size thread?In order to solve the problem of time synchronization of data acquisition between different hardware devices in the detection system,a data acquisition synchronization controller is developed to synchronize the time acquisition of coordinate machine and laser displacement sensor measurement data.In the calculation of thread parameters,digital filtering algorithm is used to process the original thread profile data collected.Then,the filtered thread profile scan data is segmented by using the trigonometric Fourier fitting method.The segmented data are obtained by using the first-order linear regression equation to obtain its slope,intercept and other parameters,Refer to the thread of major diameter,pitch diameter,minor diameter,half of thread angle,thread angle,pitch of geometric parameter definition to calculate of thread parameters,Compared with the parameters obtained from the query of the standard thread database,finally gives the eligibility of test thread to judge the results.