Liquid Penetrant Inspection (LPI) is a widely used and low cost inspection method used to locate surface breaking defects in all non porous materials such as metals, plastics and ceramics.
Liquid Penetrant Inspection (LPI) is a widely applied and low-cost inspection method used to locate surface-breaking defects in all non-porous materials (i.e., metals, plastics, or ceramics).
LPI is based upon capillary action, where a low surface tension fluid penetrates into clean and dry surface-breaking discontinuities. A Penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has been allowed, the excess penetrant is removed and a developer is applied. The developer helps to draw penetrant out of the discontinuity so that an invisible indication becomes visible to the inspector. Inspection is performed under ultraviolet or white light, depending on the type of dye used - fluorescent or non/fluorescent (visible).
We perform the test in accordance to ASTM SE 165: Standard Test Method For Liquid Penetration Examination.