The Ultrasound-based Precision Measurement Method Of Cavity Size

With the continuous development of the recent manufacturing technology and the rapidly growing demand for cavity components of precision parts, its application continues to grow in the areas of aerospace, steel industry, weapon industry, railway transportation industry, machinery manufacturing industry, nuclear industry, medical science, oil exploration and other areas. The inner scales measuring technique for precision workpiece provide a strong test guarantee for the manufacturing and processing of cavity components of precision parts and thus it plays an important role in the development of new technologies.On the basis of in-depth study of modern non-destructive testing technology, We propose the ultrasound-based precision measurement method of cavity size and develop a set of real-time display system which is called the ultrasound-based precision measurement method of cavity size.Based on the problems that the photoelectric detection method and the X-ray testing method cannot provide the ideal accuracy when they are applicated to detect the cavity of small workpiece with diameterΦ6mm and the general probes cannot stretch to the internal of the workpiece, we propose a high-frequency ultrasonic reflection technique which is used to measure the cavity size of diameter tube. The method uses ultrasound to measure the thickness by reference to wall thickness. It can convert the problem of measuring inner dimension into the problem of measuring the thickness of the wall. It can extract information about the wall size of workpiece through signal processing, feature extraction and other methods. By using this information, we can measure the size of cavity. Compared with the test results showed by a venire caliper and screw micrometer, we can get the conclusion that the immersion focusing probe with center frequency of 10MHz can accurately detect the cavity of the workpiece. The experiment shows that the method gives consideration to the accuracy and computational efficiency of the workpiece’s cavity parameters. It can get data supplely and effectively. There are other advantages of this method such as stable performance, easy installation, and lower power consumption and penetration ability. This method truly achieves the precision measurement of the workpiece.In summary, the system meets the requirements and conditions of customers and merchants, and has made good application effect.