Posted By: Steve
Link to AJR
Published: 06/12/
Times Read:
The general lighting industry has embraced LEDs as the preferred technology of choice over incandescent and fluorescent bulbs due to higher flexibility and fewer safety concerns. However, the nondestructive testing community has trailed in adoption of LEDs due to the special lighting requirements and challenges posed by fluorescent methods such as liquid penetrant testing or magnetic particle inspections.
With regulatory exemptions for NDT expiring in recent years and advancements in LED technology and manufacturing, high-intensity LED UV-A light sources are now the go-to solution for NDT professionals.
While flexibility is one of the main advantages to LED technology brings to NDT, it also means more details are required to specify the right performance for nondestructive testing. For a lamp to be useful in fluorescent penetrant or magnetic particle inspection, many factors must be considered.
Peak Wavelength & Emission Spectrum
Peak wavelength is the most important factor when selecting an LED lamp for fluorescent inspection.
When the formulas for penetrants and magnetic particle materials were created, the default UV-A source was mercury-vapor, which produce a single UV-A peak at 365.4 nm, the elemental emission line of mercury. Therefore, all fluorescent penetrants and magnetic particle materials are tuned to fluoresce under UV-A at 365 nm.
With LEDs, the peak wavelength is variable and depends on the individual LEDs used when the UV lamp is manufactured. To make sure that an LED UV-A lamp produces fluorescence in penetrants and magnetic particle materials, the LEDs must have a peak wavelength within the range 360-370 nm.
It is also important to consider the UV-A emission spectrum since the UV-A emission of an LED is much wider than that produced by mercury-vapor. At the tail end the spectrum includes some emission in the visible light range above 400 nm which can be observed as a deep violet glare from the lamp. Fluorescent penetrant and magnetic particle inspections are performed in a dark environment to increase contrast, and visible light contamination will degrade the inspection. For inspections to aerospace specifications, like ASTM E, Nadcap AC and Rolls-Royce RRES , this deep violet glare is not acceptable. For that reason, any lamp used for aerospace inspection, such as the EV, must include a UV-A pass filter to block visible emission.
Beam Profile & Working Distance
With LED lamps, you are not limited to a single configuration to perform all NDT inspections. Lamps can be designed for specific applications and uses.
Lamps designed for close-up inspection will have a focused intense spot, but a small beam area. The beam area of an LED UV-A lamp is the measure of how much surface is above the minimum 1,000 µW/cm2 irradiance required for inspection. To achieve a wide beam area, an array of LEDs is needed.
However, if an array is used too close to the inspection surface, patterns of bright and dim spots will result. This is the trade-off between working distance and beam area.
Lamps with a small beam area are useful for inspecting tight areas like holes, weld joints, and internal surfaces. But when used on large structures, a small beam can create &#;tunnel vision&#; where the inspector is focused on a single area and indications just outside of the beam area can easily be missed.
A lamp with a large beam area will provide UV-A irradiation to the area peripheral to the inspection. This allows the inspector to quickly locate and identify fluorescent indications in the peripheral area for closer inspection.
The working distance of an LED UV-A lamp is the minimum distance required to provide even coverage.
When placed very close to a surface, individual LEDs in an array will project separate beams with dim areas in between. Such uneven coverage degrades the quality of the inspection, and could lead to missed indications. But as the lamp is moved away from the surface, the beams from individual LEDs will merge into a smooth, even profile.
Inspection should only be performed when the lamp is positioned farther than minimum working distance.
Power Supply
Working at low voltage, an LED UV-A lamp can operate on battery power for several hours. This makes the lamp very portable, and field inspections become quick and simple.
However, there is a concern with battery-powered lamps because LED intensity is directly related to supply voltage and current. As a battery is used, the voltage and current drops, giving a characteristic discharge curve. With an LED UV-A lamp, this can result in decreasing intensity over time, eventually dropping below the minimum 1,000 µW/cm2 requirements.
Advanced lamps incorporate constant-current circuits that monitor the battery discharge. These lamps will automatically turn off if they are not able to maintain 1,000 µW/cm2 minimum intensity. Knowing the type of battery and the discharge curve is important to ensure quality inspections with battery-powered LED UV lamps.
Certification Requirements
Different industries have different inspection requirements and tolerances.
The aerospace NDT industry, including fluorescent penetrant and magnetic particle inspections, have high level specifications on all aspects of the process. After five years of study, the aerospace requirements for LED UV-A lamps were established in ASTM E. This standard provides baseline performance for lamp manufacturers to meet for use with fluorescent inspections.
An LED UV-A lamp that is certified by the manufacturer to ASTM E, like the EV hand-held UV lamp, is acceptable for use by all aerospace primes and OEMs, and meets Nadcap audit criteria. However, these requirements only apply to lamps used for final aerospace inspection. Lamps used elsewhere in the process, such as penetrant wash or rinse stations, typically do not require full ASTM E certification.
For non-aerospace industries like welding, energy, pipeline or field inspection, there are fewer certification requirements. More rugged industrial inspections are often done in less-than-ideal conditions so more intense UV-A is needed to make fluorescent indications visible. However, research has shown UV-A intensities above 10,000 µW/cm2 at 15 inches / 38 cm can cause fading of fluorescent dyes and pigments.
An LED lamp for industrial applications, like the newly released EV dual-light UV lamp, should include a manufacturer&#;s certificate of conformance that includes the maximum UV-A intensity, regulated below 10,000 µW/cm2. The certificate should also include peak wavelength within the range of 360-370 nm to ensure the lamp has the proper emission spectrum to induce fluorescence.
Wrap-Up
LED lamps are a valuable advancement to nondestructive testing by providing greater flexibility in design and application, and improved safety. However, there are many considerations to choosing the right LED UV-A lamp for use in fluorescent inspection. Factors such as emission spectrum, beam area and power supply must be considered when using LED lamps. Certification requirements are also a consideration for aerospace and other high-spec industries.
By carefully considering their testing needs before investing in a LED UV lamp, NDT professionals can be confident they are getting the right tool to help make their fluorescent penetrant testing and magnetic particle inspections faster and more efficient.
Source:
Geis, David. "How to Select the Right UV-A Lamp for Your NDT Needs." Magnaflux Blog, 8 April ,
https://www.magnaflux.com/Magnaflux/Blog/Select-LED-UV-Lamp-for-NDT
Labino NDT UV lights: An innovative, versatile, and penetrant resistant UV light solution
Non-destructive testing solutions are often designed as a one-size-fits-all product, but that might not capture all of your unique industrial applications and demands. Whether you work in the military, aerospace, oil & gas, manufacturing, criminal investigation, or another sector, your testing conditions and requirements might be so specialized that you have had difficulty finding an NDT UV light supplier that understands you.
Labino &#; the global leader in NDT UV lights &#; was formed with that exact mission in mind. Their range of original, first-to-market UV inspection lights and measurement instruments have had a major impact on the NDT testing industry in recent years.
GX Orion is the world&#;s first waterproof overhead UV inspection light for NDT
Up until Labino launched their penetrant resistant UV light, the GX Orion, NDT professionals lacked an overhead UV light that could operate in inspection areas prone to water intrusion. The GX Orion &#; certified with an ingress protection marking of IP68 waterproof and dustproof &#; can be used to cover large areas because of its modular design. The oil & gas industry is just one example of where a light such as this is a critical addition to NDT testing capabilities. Most impressively, since launching four years ago, there have been exactly ZERO LED failures recorded in the field with an installed base in over 50 countries.
The GX also has the endorsement of numerous certifications, including:
When selecting your GX Orion, you can choose from three models, all of which come with a PLC interface:
GX Orion Remote (&#; 1,500 &#; 7,000 μw/cm2)
GX Orion UV & White Light (&#; 7,000 μw/cm2)
GX Orion UV Only (&#; 4,500 μw/cm2)
Remarkably, the UV light beam profile is homogenous without any footprints showing from the LEDs, shades, dark spots, or other disturbing defects. Further, your GX Orion series NDT UV light will come with a 3-year warranty.
BB 2.0 Series handheld penetrant resistant UV light is the most powerful beam on the market
Labino&#;s BB 2.0 series gives you a new handheld UV light system with 8 UV LEDs. It boasts the largest, smoothest, and uniform (lacking parallelism) beam profile on the market, with the BB 2.0 Artemis currently the world&#;s strongest beam. One unique feature about the BB 2.0 is that it is 100% free from UV-B and emits almost no white light. The U.S. Military and oil & gas industries have already reaped the benefits.
The BB 2.0 Series also has the endorsement of numerous certifications, including:
ASTM E-
Rolls-Royce RRES
Airbus AITM6-
Pratt &Whitney
The Boeing Co
ISO -12
USAF requirements
Penetrant resistant
IP68 Waterproof
When selecting your BB 2.0 Series, you can choose from three models:
Ikaros (&#; 4,000 μw/cm
2
, 10.6&#; Beam diameter > μw/cm
2
)
Helios (&#; 9,000 μw/cm
2
, 11&#; Beam diameter > μw/cm
2
)
Artemis (&#; 22,000 μw/cm
2
, 10.25 &#; Beam diameter > μw/cm
2
)
All three models are lightweight, penetrant resistant, and come with an instant-on function, so they are easy to work with and you get full power immediately.
Apollo 2.0 UV & White Light Meter is high-tech and easy to use
Rounding out Labino&#;s recent offerings is the Apollo 2.0 UV and White Light Meter, which takes accurate UV-A irradiation and visible light measurements simultaneously. A key component of this product is the fully non-fluorescent bandpass filter. With auto-ranging and concurrent visible light UV-A measurement, you will get back fast measurements. It is a perfect complement to the BB 2.0, MidBeam 3.0, and UVG3 2.0 on the Olympos Stand.
Additionally, Apollo 2.0 is:
The Apollo 2.0&#;s sensors take measurements and utilize Bluetooth to transmit readings. With the wireless sensor, you can measure from a distance of up to 16 feet. You can choose from either a single kit or double kit, the latter including an extra wireless sensor unit.
Berg Engineering is here for all your Labino NDT UV light needs
Berg Engineering is proud to be a Labino service center. We offer you a full package of support to make sure your Labino NDT UV LED Lighting experience is a success, including sales, training, and support. We offer Magnetic Particle Inspection (MPI) and UV training both remotely and at your worksite. We have invested our time and expertise to ensure this product delivers as promised. At each step of your purchasing journey, from product research to purchase, to post-purchase support and training, we are by your side ensuring things run smoothly.
According to Stephen Berg, CEO of Berg Engineering, &#;Labino&#;s GX Orion demonstrates exactly why Labino has had such an impact in the NDT industry. It is the world&#;s first waterproof overhead UV lamp. We&#;ve already seen our clients succeed with this release, and we can&#;t wait to see what problem Labino will solve next!&#;
Resources
Berg Engineering
Labino
Berg Engineering
Berg Engineering and Sales Company has been supplying nondestructive and material testing equipment since . We represent the world&#;s leading manufacturers of nondestructive testing (NDT) testing devices. We publish articles that cover topics of interest for current and future members of the NDT community.
view their site
Want more information on Surface Roughness Tester Manufacturer? Feel free to contact us.
Comments
Please Join Us to post.
0