Patent ID: 9535040
Date: 2017-01-03
CPC Classifications: G01N

Claim:
1. A method of testing a connection between a metallic workpiece and a plastic compound for the presence of a cavity in the connection, said method comprising: exposing the plastic compound to ultrasonic signals of a predefined test frequency and pulse length from a metal side of the workpiece, using at least one ultrasonic probe; detecting the ultrasonic signals reflected by a flaw in the plastic compound; converting the ultrasonic signals into electrical signals; subjecting the electrical signals to a threshold observation to determine whether the flaw indicates the presence of a cavity, wherein the test frequency of the ultrasonic signals is set in a range of 1 to 10 MHz such that attenuation of the ultrasonic signal is minimal after traveling through a plastic skin of the plastic compound; and exposing the plastic compound to ultrasonic signals from the metal side of the workpiece and using the at least one ultrasonic probe with test frequency and pulse length which are readjusted such that the presence of the cavity is determined by a signal amplification or signal weakening of electrical signals in comparison to the electrical signals generated by a flawless plastic compound as a result of interference between the readjusted ultrasonic signals reflected from a top side of the plastic skin at an interface between steel and plastic skin and from a bottom side of the plastic skin at an interface between plastic skin and cavity.