Strength & Application Of Ultrasonic Immersion Thickness Measurement

Water immersion thickness measurement is a method of ultrasonic principle thickness measurement, which is characterized by the use of water as a coupling agent between the workpiece and the probe. This detection method is suitable for irregular workpieces or other workpieces that are difficult to couple. Detection of the workpiece and the probe together into the water, the probe needs to be a certain distance from the workpiece (known as the thickness of the water layer). After the ultrasonic wave is emitted, it goes through the water to the surface of the workpiece and then turns into the inside of the workpiece, and then the thickness of the workpiece can be correctly displayed through the adjustment of the A-scan waveform on the display screen.

Ultrasonic thickness gauge is based on the principle of ultrasonic pulse reflection to carry out thickness measurement, when the ultrasonic pulse emitted by the probe through the object under test to reach the material interfaces, the pulse is reflected back to the probe by accurately measuring the ultrasonic propagation time in the material to determine the thickness of the material under test.
Ultrasonic water immersion thickness measurement method is to put the probe into the water, its emitted ultrasonic waves will produce a number of water interface reflection wave, at the same time the object to be explored also produces reflected waves, due to the ultrasonic propagation speed in the water and the material to be measured is different, through the adjustment of the probe and the object to be explored by the thickness of the water layer between the object to be explored, so that the bottom of the object to be explored is located in the secondary water interface reflection wave before.

There are two general approaches to water immersion: partial water immersion and whole water immersion.

1.Partial Water Immersion System

The partial water immersion system can increase work efficiency.

2.Whole Water Immersion System

This kind of system uses immersion probes to measure the tubes and bars,it is suitable for automated measurement of workpieces with rough surfaces, complex shapes and poor coupling conditions, such as tubes and bars.

We received a sample cartridge material from a customer (diameter 30-40mm, wall thickness 5-9mm or so), the cartridge is sintered at high temperature and high pressure and has a microporous distribution. The customer requested to measure the wall thickness to check the uniformity and minimum thickness.

Due to the special structure of this material, conventional ultrasonic thickness measurement method is difficult to receive the bottom echo, can not realize the measurement. After practice, usingYUSHI PM5 Gen2 ultrasonic thickness gauge for the water immersion thickness measurement , the waveform is clear and the thickness value is very accurate.

In the daily ultrasonic measurement work, there are some workpieces that cannot be measured by the common direct contact method for ultrasonic thickness measurement due to special reasons such as rough surface and irregular shape. In order to focus the sound energy, should be used to focus the probe, probe frequency is selected according to the material characteristics. Water immersion thickness measurement is highly sensitive, liquid coupling loss of sound energy is small, water immersion thickness measurement can overcome the roughness of the surface of the workpiece or the surface shape of the loss of acoustic energy caused by the factors. And because there is no need for close coupling, it improves the working efficiency of the measurement and is suitable for the secondary development of online measurement.