Fluorescent penetrant inspection

With its brilliant yellow glow caused by its reaction with ultraviolet radiation, FPI dye sharply contrasts with the dark background.

Defects can vary but are typically tiny cracks caused by processes used to shape and form the metal.

Sandblasting to remove paint from a surface prior to the FPI process may mask (smear material over) cracks making the penetrant not effective.

This can cause lost time and money in reworking, over-processing, or even scrapping a finished part at final inspection.

The fluorescent penetrant is applied to the surface and allowed time to seep into flaws or defects in the material.

Dwell time varies by material, the size of the indications that are intended to be identified and requirements / standards but is generally less than 30 minutes.

This highly controlled process is necessary in order to ensure that the penetrant is removed only from the surface of the material and not from inside any identified flaws.

This must take place in a dark room to ensure good contrast between the glow emitted by the penetrant in the defected areas and the unlit surface of the material.

Upon successful inspection of the product, it is returned for a final cleaning before it is either shipped, moved on to another process, or deemed defective and reworked or scrapped.