EDM Notch Reference Standards
In the world of NDT, our ability to consistently assess the severity of discontinuities relies on the use of NDT reference standards. We can think of them as comparators or constants against which other things are measured. Because it would be impossible to obtain samples containing real and consistently reliable defects for use as reference standards, the NDT industry must rely on manufactured samples; intact parts containing artificial discontinuities. By careful comparison to these, a technician is able to make a pass or fail determination. Like any other gage, the accuracy of NDT reference standards is critical, and knowing exactly what has been machined, and to what extent, is vital.
PH Tool is highly-specialized in producing artificial discontinuities known as electrical discharge machined (EDM) notches. EDM notches are typically produced from an otherwise acceptable production item supplied by the manufacturer of the part or the test lab performing the inspection. A length of tubing, a section of wheel, a turbine blade (almost anything imaginable!) can be shipped to PH Tool for machining of EDM notches.
The EDM process is a nonconventional machining process in which material is removed very precisely under carefully controlled conditions. The cutting is done with an electrode that is configured to yield the artificial defect desired. The flexibility in electrode manufacture allows us to create complex shapes that can follow irregular part geometry with a high degree of accuracy. See some examples of EDM Notch Reference Standards in the gallery below:
For more information on the EDM notching process, please follow this link: What is EDM?