Penetrant testing

Penetrant testing is another test method used globally to detect surface discontinuities. Parts can be locally or fully inspected. It can be used on all metals and other non-porous materials such as ceramics, some plastics and composites. PT can be can be performed manually in situ during maintenance (MRO), or automated close to a manufacturing line (OEM).

How does PT work? A dye solution is applied to the surface to penetrate any surface breaking cavity. Once the excess solution is removed, a developer is applied to draw out any unseen penetrant. With visible dyes, a colour contrast between the penetrant and developer makes the ‘bleed-out’ easy to see. With fluorescent dyes, UV light makes the ‘bleed-out’ fluoresce brightly, allowing imperfections to be seen.