What kind of flaws are relevant to plastic pipe production?
Methods for flaw detection require a precise definition of what the term “flaw” means. Unfortunately, production sites very often speak different languages on this matter. Wall thickness measurement itself could be taken as a kind of flaw detection, as when tolerances are exceeded or fall below the minimum; this is a kind of control, too. However, this is not what is meant by the “classical” use of the term “flaw detection,” and wall thickness measurement is already a standard for in-line gas pipe testing (it saves raw material costs!). We will not concentrate on this here, but refer you to the article, “Ultrasonic for Plastic Pipe Extrusions (by R. Diederichs)”[1] that describes the state of the art and outlines some basic problems of ultrasonics applied to plastics. The statistical/spiral wall thickness in-line measurement should be a precondition that is applied with a separate system. This function could also be integrated into the flaw detection system as it is established. Wall t
