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Chapter 17: D. Testing Methods 181
• To ensure customer satisfaction through ensuring product reliability
and integrity
• To ensure the safety of the end user
• To compete within the currently evolving market by maintaining
reputation through high quality products and better product design
• To minimize waste, which leads to minimizing overall manufacturing
cost and maximizing profit
• To ensure the flexibility and adaptation of products to market changes
Methods of Nondestructive Testing
The National Materials Advisory Board (NMAB) Ad Hoc Committee on Nondestructive
Evaluation has adopted a system that classifies methods into six major categories:
visual, radiation, magnetic-electrical, mechanical vibration, thermal, and
chemical-electrochemical (ASNT 2008) (Wenk and McMaster 1987) (McMaster
and Wenk 1951). Within these categories the most commonly used methods are:
visual, X-ray, Eddy current, ultrasonic, magnetic, and liquid penetrant.
Visual Method. The visual method is the oldest and most common method of
examination; it is used in a variety of industrial and commercial applications (Aircraft
NDT 2008). Usually the examiner follows procedures that might vary from
simple to very complex. Visual tools also vary from using the naked eye to very
complex remote-controlled equipment. Figure 17.1 shows one type of the equipment
that might be used to inspect products or materials. Some visual tools can
be controlled with a robot for inspecting hazardous or tight areas such as nuclear
Part III.D.1
Figure 17.1 Visual inspection ensures consistency.