A Key Technology for Surface Crack Detection in Modern Industry
In critical industries such as aerospace, automotive, shipbuilding, nuclear power, and precision manufacturing, even the smallest surface crack or defect can lead to catastrophic failure. That’s why Fluorescent Penetrant Inspection (FPI) has become a widely used and highly effective method of non-destructive testing (NDT) for detecting surface-breaking flaws on non-porous materials.
How Does FPI Work?
Fluorescent penetrant inspection works by applying a highly sensitive fluorescent liquid dye to the surface of the test object. This dye penetrates into any open surface discontinuities such as cracks, porosity, seams, or laps. After a dwell time, the excess penetrant is carefully removed and a developer is applied to draw out the penetrant from the defects. When viewed under ultraviolet (UV-A) light, any remaining penetrant glows brightly, revealing the flaw.
The Standard FPI Process Includes:
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Pre-cleaning – Removing oil, grease, and contaminants
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Penetrant application – Applying fluorescent dye
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Dwell time – Allowing dye to seep into flaws
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Excess penetrant removal – Carefully cleaning the surface
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Developer application – Drawing out penetrant from flaws
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Inspection under UV light – Visual inspection in a darkroom
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Post-cleaning – Final cleaning if necessary
Advantages of FPI
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High sensitivity to surface defects
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Cost-effective and easy to automate
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Ideal for complex shapes and critical components
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Applicable to metals, ceramics, plastics, and composites
Applications
FPI is commonly used to inspect:
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Aircraft engine parts (blades, disks, landing gear)
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Automotive components (crankshafts, gears)
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Welds and castings in pressure vessels or pipelines
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Precision mechanical parts and medical devices
About Us – Your Trusted NDT Solution Provider
Nuke NDT is a leading manufacturer of automated fluorescent penetrant inspection machines, magnetic particle testing systems, and custom industrial NDT lines. As a national high-tech enterprise with over 60,000 square meters of manufacturing space, we offer:
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Full FPI inspection stations and conveyor lines
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Manual, semi-automatic, and fully automatic solutions
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Integrated UV lighting systems, drying ovens, and developer booths
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Professional design for aerospace, automotive, fasteners, and more
We provide turnkey solutions tailored to your part dimensions, inspection standards, and throughput requirements.
Looking for a reliable and cost-effective FPI system?
Get in touch with Nuke NDT – where quality meets innovation in non-destructive testing.
