Liquid (Dye) Penetrant Inspection
Liquid (or dye) Penetrant Inspection (LPI) is used for detecting surface-breaking flaws on any non-absorbent material surface. This method can be used to detect casting, forging and surface defects such as surface porosity, fatigue and hairline cracks or leaks. Penetrating liquid (dye) is applied after the area is cleaned (degreased), excess penetrant is removed, and a developer applied. The area is then visually inspected to identify any defect areas. Fluorescent penetrating liquid (dye) can be used for more intricate parts.