(FPI) Fluorescent Penetrant Inspection
What Is Fluorescent Penetrant Inspection (FPI)?
Fluorescent Penetrant Inspection (FPI), also called Dye Penetrant Inspection (DPI) with fluorescent dye, is a non-destructive testing (NDT) method used to detect surface-open discontinuities such as cracks, porosity, laps, seams, and cold shuts in materials.
- It's suitable for non-porous materials - metals, plastics, ceramics, glass, etc.
- It provides high sensitivity to small surface breaks.
- The fluorescent dye under UV/black light makes defects highly visible.
UT ULTRA SONIC TESTING
Principle of FPI
FPI relies on the capillary action of a liquid penetrant:
- A liquid penetrant with low surface tension is applied to the test surface.
- The penetrant seeps into surface-open defects (by capillary action).
- After appropriate dwell time, excess penetrant is removed.
- A developer is applied - drawing remaining penetrant out of flaws.
- Under ultraviolet (UV) light, the fluorescent dye glows, revealing defects.
This method does not detect subsurface or internal flaws - only defects open to the surface.
Typical Applications
FPI is widely used in industries including:
- Aerospace - turbine blades, landing gear, fasteners
- Automotive - engine parts, gears
- Manufacturing - welds, castings, forgings
- Railway & Shipbuilding - structural components
- Power Generation - rotors, shafts, valves
It's especially useful for components that are complex shaped and critical in service.
Versatility
Available in both manual and semi-automatic models to suit various testing needs.
High Capacity
Head shot and coil shot capabilities ranging from 1500 Amp to 10000 Amp.
Comprehensive Service
We offer installation services to ensure seamless setup and operation.