Hello, the sample size required for ultrasonic scanning. Generally speaking, ultrasonic scanning requires that the size of the sample should be not less than 2mm and not more than 200mm, and the shape of the sample should be regular, without too many irregularities, otherwise the accuracy of the test results will be affected. In addition, the surface of the sample should be smooth without too many stains, otherwise it will also affect the accuracy of the test results.