What is flourescent penetrant inspection?

Fluorescent penetrant inspection (FPI) is a non-destructive testing method used for detecting surface-breaking defects in metal, plastic, or ceramic materials. In this inspection technique, a fluorescent dye penetrant material is applied to the surface of the test piece, which is then cleaned and dried. A developer is then applied to the surface, which draws the penetrant out of the cracks, porosity, and other surface discontinuities, making them visible to the inspector under ultraviolet light.

FPI is commonly used in manufacturing, aerospace, automotive, and welding industries to detect defects and cracks in metal parts such as engine components, turbine blades, and aerospace structures. This method is highly sensitive and can detect flaws that are not easily visible to the naked eye.

The primary advantage of FPI is that it is a cost-effective way of detecting surface defects and cracking without causing any damage to the component being tested. Moreover, it is a straightforward and reliable method for conducting inspections. However, FPI has limited sensitivity to subsurface defects and may not detect virgin discontinuities in thick materials.