Magnetic particle inspection using hand yoke and UV-Yoker

by T. Elias, Technical Sales Manager, MR-Chemie

Benefits of Hand Magnets:

The well-known advantages of hand magnets, such as their versatile applications, short setup times, and comparatively low acquisition costs compared to, for example, high-current generators, often lead to purchasing decisions.

Disadvantages of Hand Magnets:

The inspection with a hand magnet, especially in fluorescent crack testing, often presents a challenge to operational processes due to resulting waiting times in production. Additionally, the operation of the three essential components – hand magnet, testing material, and UV light – usually requires two hands constantly switching. This may sound unspectacular, but during an 8-hour shift, one quickly realizes the challenges.
In practice, this way of working has resulted in high inspection times and often frustration for the user, as there always seems to be a need for a third hand to work fatigue-free and efficiently.


Fortunately, there is now a remedy in the form of smart solutions, one of which I would like to introduce to you, as I have been more than convinced of it since my time as a user.

The marriage of magnet and UV lamp!

This idea is as simple as it is ingenious and has been implemented with our hand magnets of the MR-50 and MR-56 series and the complementary UV yokers of the MR-90 and MR-94 series for both fluorescent and daylight testing.
This combination significantly reduces testing times and renders the helpful third hand unnecessary, which should also eliminate frustration for the user.

Figure 1: MR® 50 Hand yoke with UV Yoker MR® 90
Figure 2: MR® 56 Hand yoke with UV Yoker MR® 94

The yokers are mounted using a clamp connection (MR-94), ensuring retrofitting of older hand magnets, or in combination with the new generation of hand magnets, optionally through a screw connection (MR-90) directly on the hand magnet. If the modules are not needed at any time, disassembly is quick and easy.

The housings are made of aluminium in the MR-90 version and robust Pertinax in the MR-94 version, designed for daily use even in demanding work areas. The yokers are powered by integrated electronics immediately upon switching on the hand magnet. Due to the thoughtful selection of materials, the additional weight is kept within acceptable limits at 61g or 217g.

With an average lifetime of >5000 hours for the LEDs you are well prepared for intensive testing. At a distance of 10 cm from the test surface, these little helpers provide a more than adequate irradiance of 25 W/m² or 3000 lux illuminances with a light distribution of approx. Ø120mm.

Figure 3: Crack-like indications under UV-light using MR® 50 Hand yoke and MR® 90 Yoker. Fluorescent magnetic powder suspension MR® 761F.

!!At this point, an important note on occupational safety!!

The UV version of the lamps is classified in risk class 2 according to DGZfP data sheet EM 06, so please always ensure that all necessary protective measures are taken.
Hint: Our MR-480 UV Light Dosimeter can be used to reliably monitor UV exposure in the workplace.


The advantages of a combination of hand yoke and yoker are evident in many application areas with shortened testing times and ergonomic operation. Working with the mounted yokers does not restrict freedom of movement. The easy handling, minimal weight, and performance of the yokers are good arguments for those who want to work smartly and reliably in the future.

Your contact

Picture of Thomas Elias

Thomas Elias

Technical Sales Manager

02303 95151-25


With high quality products for
Non-Destructive Testing, 3D Laserscanning
and the hygienic sector


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