The application and research of high-frequency ultrasonic reflection technique used in the measurement of small diameter’s tube 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 diameter Φ6 mm 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. 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 10 MHz 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. It is suitable for the precision measurement of the workpiece.

► We design the structure according to the chip size of probe and its focal length.
► Making detection by using two single-probes fixed in the same horizontal line.
► Using scanning spiral belt formed by rotation to cover the pipe.
► Achieving coupling between probe and small diameter’s tube through full immersion.
► Using real-time detection to response cavity information of small diameter’s tube.