Press There are many different forms of NDT/NDE. Some are considered volumetric, and others are categorized as surface only.
Visual Testing, Magnetic Particle and Liquid Penetrant Inspections are surface only, whereas Ultrasonic and Radiographic are considered volumetric, meaning that they are able to “look” inside the component to find defects that would not be visible without cutting into the component.
Source: Types of Non-Destructive Testing & Their Advantages | Saskarc Group
