The technological leap from discharging lamp-based UV-Radiation
sources to LED-based ones in NDT is equal to the change from the
annoying, uncomfortable, unloved, but necessary step-child to the
high-quality, professional and powerful tool
with additional features!!!

Subsequently you will receive information about technological and practical backgrounds as well as the absolute essentials for an appropriate specification, parameterisation, qualification, certification and approval of UV-LED-Lamps for non-destructive testing (NDT), to ensure the necessary inspection quality in fluorescent leak detection.

The fluorescent magnetic particle testing (MT) and penetrant testing (PT) are the most powerful NDT-procedures when it comes to finding even the smallest surface defects.

The UV-Radiation source has, amongst other things, a significant role for the error detection as it directly depends on the conformist function and reliability of the UV-Lamp.

If, for instance, the UV-Radiation source does not deliver the necessary intensity in the required wavelength range and in the required „technical“ quality, relevant indicators will not become visible and the inspector misjudges the faulty, highly critical safety parts and constructions as error-free as he cannot see the real existing indicators.

The quality of the UV light source is of fundamental importance for an optimised, safe, reliable and inexpensive audit.

The non-destructive, fluorescent testing is the by far most demanding area of application for UV-LEDs, as a malfunction of the lamp can barely be noticed by the inspector, error indicators do not become visible and no further instance reviews the testing process.

Perfectly adapted UV-LED luminaire systems can not only drastically improve the testing process as well as the working conditions, but also offer a long-term reduction in costs and drastically improve the work safety.

You can find a compact overview by Marc Breit in the NDT-Newspaper 139 by the German Society for Non-Destructive Testing (DGZfP).

Download the specialist article specialist article in the NDT-Newspaper (April 2014) (PDF) or read it directly on the DGZfP Website.

In the upcoming weeks you will be receiving further details, information and explanations behind the links between the individual paragraphs all about the topic of UV-LED-Technology in NDT.

Should you have any questions on short-call, need any information or support, do not hesitate to contact RIL-CHEMIE through the above-mentioned contact details.

I. Basic Information

a. The testing practice and the currently mild standards (State 5/2014)

b. Technical basics of the fluorescent magnetic particle testing (MT) and penetrant testing (PT)

c. Top priority of fluorescent leak detection processes in NDT:
optimum, high contrast perceptibility of indications for the human eyesight

d. The human eyesight

e. Technological and optical requirements for light and radiation sources for visual evaluation

f. What is UV-A-Radiation and visible light?
The spectral emission of a lamp and its importance for fluorescent leak detection

g. Risks associated with the usage of inadequate UV-Lamps

h. Responsibility for the fulfilment of the requirements and liability of the auditors

i. Practical- and occupational safety risks using traditional UV-Radiation sources

II. The change in technology from the simple discharge lamp (mercury-vapour lamp, xenon-lamp, metal halide- or halogen burner) to semiconductor UV-LEDs as a radiation source for NDT and its meaning for the testing process.

a. The difference between a simple electronic device and an electronic system

b. Quasi standard in bulb-based lamps and the compelling necessity of an extensive qualification and parametrisation of UV-LED-Lamp systems

c. technical basics of LED-Technology

d. Characteristics of using UV-LEDs

e. Requirements for UV-LED luminaire systems for NDT

f. Parameters to describe and specify UV-LED-Lamps

g. UV-Intensity-Stabilisation: a simple parameter to check that gives a clear indication about the quality of the UV-LED, its lifetime as well as wavelength stability, practicability, processing quality and condition of the overall system.

III. Advantages using adequate UV-LED-Radiation sources in fluorescent crack detection

a. General advantages of LED-Technology

b. Technical advantages of LED-based UV-Radiation sources

c. Practical advantages of using high quality UV-A-LED-systems

d. Advanced functionality that only just becomes available through LED-Technology

e. Extended occupational safety

f. Commercial advantages when using optimised UV-LED-Technology instead of traditional discharge lamp-based UV-Lamps

g. Additional advantages when using UV-LED-Lamp-Systems with secu-chek®-Technology by RIL-CHEMIE

IV. Relevant parameters to describe UV-LED-Sources for NDT

a. UV-Intensity

b. Spectral emission

c. Visible emission and white light proportion

d. UV-Intensity-Stability, degradation and lifetime

e. Minimum working distance

f. Uniform distribution of radiation

g. Intensity behaviour at the edges

h. Perceived and illuminated area

i. Allowed operating conditions

j. Recommended operation purpose

k. Constancy and residual ripple of UV-Radiation

l. Maintenance and overhaul cycles

m. Number of LEDs

V. Requirements for the qualification and specification of UV-LED-Lamps for NDT

a. Type testing and sample inspection

b. Testing every individual lamp

c. Specification and certification through the manufacturer

d. Qualification and approval of the UV-LED-Lamp for the specific application and testing requirements through the testing responsible person.

e. Working ergonomics and stress-free vision

f. Why only flicker-free, non-pulsing UV-LEDs with minimal residual ripple are acceptable

VI. State of the standardisation (Beginning of 2014)

a. DIN / EN / ISO 3059 (Foundation for DIN / EN / ISO 9934 (MT) and DIN / EN / ISO 3452 (PT))

b. ASTM / AMS / SAE (American standardisation)

c. NADCAP (Accreditation for suppliers of the aviation industry)

d. AIRBUS

e. MTU Aero Engines

f. Rolls-Royce and ADS SIG NDT UK

g. Pratt & Whitney (P&W)

h. General Electric Aviation (GE)

i. SAFRAN Group (Turbomeca, Snecma. Hispano-Suiza)

VII. Tabular comparison between the new and the old technology

Protection Notice:

This technical information and the content of this website and the following ones are intellectual property of RIL-CHEMIE Marc Breit.

The usage, exploitation, publication and sharing of the content or parts thereof is prohibited if not explicitly stated otherwise. In the event of contraventions compensation for damages will be claimed. All rights for designs, registered designs or industrial designs are reserved for RIL-CHEMIE Marc Breit.

© RIL-CHEMIE Marc Breit 2014