Research And Develop Of Online Pneumatic Diameter Measurement

During the manufacturing process of the electrical wire, the diameter of the electrical wire required for accurate measurement in order to reduce the production costs and comply with the national standards. The traditional manual measurement with power shut down and contact measurement cannot realize continuous measurement accurately, not only affects the quality of the electrical wire productions, but also make a waste of energy which results in the great reduction of the production efficiency and the restrictions of the lifetime of the machine. Optical caliper and Ultrasonic caliper gauge usually are used in existing online caliper techniques. The measuring optical path or wave propagation path changed with the jitter of wires and oil or water, dust, bad measurement environments during the measured work process, which leads to the low accuracy of measurement. This kind of measuring instrument is expensive and complex maintenance. Online aerodynamic diameter measuring instrument is a promising diameter measuring technique with simple structure, reliable operation and can work in metal dust, oil and water, radiation, and strong vibration harsh, and many other advantages. Therefore, the research and development of the online pneumatic contactless measurement device for the diameter of the electrical wires have an important creativity and practical significance.Firstly, the range of traditional pneumatic measuring is small and fixed. To conduct round wire diameter measurement requires multiple sets of measuring devices, its work process is relatively complex. A pneumatic conversion device with entrainment back pressure gas line as operating principle is designed in this thesis. Combined with primary and secondary air restrictor path, the measurement range is expanded and the complexity of the round wire diameter measurements is reduced. Meanwhile, drawing die with good wear resistance is used as the measuring device in order to prevent measurement error between the wire and the measuring device, which can ensure the accuracy of long-term continuous operation.Then, the data processing system based on microcontrollers and PC/104 board is structured, which includes hardware circuit electrical pneumatic air caliper conversion, analog to digital signal conversion, digital signal processing and serial communication modules. Software system includes signal acquisition, signal processing and serial communication modules. Average and digital filter algorithm processing can be done for digital signal, which provides the guarantee to achieve the precise measurement of the diameter of round wire in the bad environmentFinally, a prototype is created and multiple sets of measurement experiments were carried out, which proved developed online aerodynamic diameter measurement is stable and reliable, high accuracy, the performance of the instrument meets the design requirements.