Research On The On-Machine Measurement Technology Of Taper Thread And System Development

At present,the detection method of tool setting in the process of taper thread repair is mainly by manual testing.It is not only inefficiency,but also difficult to guarantee the accuracy.Aiming at the difficulty in detection of tool setting,a non-contact measuring method on machine based on Hall sensor is proposed,and a matching measuring system is designed.Compared with the previous measurements,this method has the advantage of high efficiency,low cost,strong anti-interference ability,etc.,and lays the foundation for realizing the automatic thread repair.Firstly,based on the in-depth study on the tool setting principle of thread repair and the measuring principle of Hall sensor,the principle of measuring thread by Hall sensor is analyzed,and the feasibility of the Hall rotary position sensor used in measuring pipe taper thread is demonstrated.Then,according to the actual measurement requirements,the system scheme of measuring system is determined,and the selection of single chip microcomputer and the design of hardware circuit are completed.According to the system control requirements,the program design of the communication system is completed,and the sensor data acquisition and storage are realized.Secondly,based on the NC pipe thread repair lathe,the on-machine measuring experimental platform of taper thread is built.The effects of measurement speed and measurement direction,distance measurement,permanent magnet shape and position conditions on measurement data are analyzed by contrast experiments.Finally,according to the quality of the data,the optimal measuring condition of the experimental platform is determined.Finally,through the analysis of the existing data processing methods,combining with the characteristic of the thread profile measuring data,an adaptive window data smoothing algorithm based on the mean deviation is proposed for eliminating noise.Then according to the linear distribution regularities of the smoothed data,the width of the local fitting window is determined.The least square method is used to fit the local data of the window,and the parameters of the feature points are obtained.After that,the algorithm mentioned above is integrated into the single chip microcomputer for on-line debugging.Through comparing the test results with the actual calculation results,the correctness of the algorithm program is verified and the measurement accuracy of the system is determined.The purpose of this research is through measuring thread section profile on machine,to realize the automation of thread processing and repair process,improve the processing efficiency and reduce the labor intensity of workers,so that it can make numerical control pipe thread repair lathe undertake more thread processing and repair tasks.