HELLING is a specialist in the design and manufacture of LED lamps equipped with UV-A LED, white light LED and also blue light LED. UV-A LED lamps are used in penetrant and magnetic particle testing with fluorescent test agent.
The increasing lifetime of the UV LED has contributed to today's widespread acceptance in surface inspection with fluorescent detection media (penetrant and magnetic particle testing). This also applies to the aviation industry sector.
LED manufacturers now guarantee a constant output intensity for a period of approximately 10,000 operating hours. UV LED area lights can be switched on and off as needed and without delay. They do not require any warm-up time and do not have to be in operation permanently. This further reduces the low energy consumption and increases the service life and service life expectancy accordingly.
Inhomogeneity visible under UV irradiation during penetrant testing with fluorescent test medium.
Magnetic particle testing with fluorescent test medium: under UV irradiation, the crack indications are clearly visible.
Advantages of the UV-A LED lamp compared to the conventional high-pressure mercury lamps used in the past are primarily:
- Significantly longer operation life
- Lower energy consumption
- Immediate operational readiness after switching on
HELLING Handheld UV-Inspector 150 for use in penetrant and magnetic particle inspection
Meanwhile, HELLING offers various designs of UV-A LED lamps:
- Stationary lamps in modular design
- Hand lamps with battery or mains operation
- Compact, handy pocket lamps
- Lamps with controll functions
- Lamps for specific industrial sectors (aviation, automotive, ...)
UV radiation (ultraviolet radiation) is electromagnetic radiation invisible to the human eye with a wavelength of 100 nm to 380 nm. This range is divided into UV-A (380 nm - 315 nm), UV-B (315 nm - 280 nm) and UV-C (280 nm - 100 nm) (DIN 5031).
UV radiation is used in various industrial applications due to its high radiation intensity, such as for hardening of films, plastics, varnishes and paints. In NDT, one predominantly uses the excitation of in the visible spectral range fluorescent substances (penetrant and magnetic particle testing).
Since UV radiation can damage the human eye and skin, the limits for permissible irradiation must be observed (see German UVV). Also, UV protective goggles should always be worn!
HELLING also limits the UV radiation of its lamps with appropriate filters. All UV-A lamps are subject to careful quality control.
Spectral distribution of an A source
At the customer's request, a certificate of analysis of spectral irradiance can be issued. This is carried out in the in-house measurement laboratory.
UV LED pocket lamps
UV LED hand lamps (battery)
UV LED hand lamps (mains)
UV LED stationary lamps
UV LED stationary lamps have also become indispensable for non-destructive materials testing in the aviation industry sector. They can be found at the test stations where fluorescent testing products are used in penetrant and magnetic particle testing.
Fig. 1: Spectral irradiance of a UV LED lamp type ZERO 500/5 AITM
Two versions of the stationary lamps series ZERO - standard or AITM
As standard, the ZERO type stationary lamps are offered in two different versions:
The "AITM" design can be certified according to AITM6-1001. The certifications are carried out in HELLING's measurement laboratory. You can find more information here.
A major difference in the design of a certifiable UV LED lamp is the choice of filter.
Tab. 1: Overview ofthe design of "ZERO" series stationary lamps, "Standard" and "AITM" versions
As standard, the stationary lamps of the ZERO series are equipped with clear glass filter. Optionally, they can be equipped with UG2A filter. For certification to AITM6-1001, they must be equipped with UG2A filter. MUGLED filter can be requested.
The following functions are no longer required by the regulations, but are still possible at the customer's request:
- Defect detection by means of a control LED and shutdown of the UV LED stationary lamp, over/under voltage control (e.g. in case of failure of an LED)
- Temperature control : Shutdown of the UV LED stationary lamp when the ambient temperature drops below 10 °C or rises above 50 °C.