The Science Behind Auto-Darkening Welding Helmet

In those loaded seconds of dark between pulling down welding helmets and the first bright spark of a welding arc, you and your helmet share a private moment. In the blink of an eye - literally, your precious organs of sight are performing very intricate and complex manoeuvers.

According to Welding Headquarters, ‘arc welding produces the full spectrum of UV radiation...The light emitted is so bright that the iris of the eye does not find sufficient time to close and limit the light reaching the retina. Over time, this can create severe problems for the welder.’

The trouble is, it gets tedious having to flip the welding helmet up and down between arcs. Auto-darkening helmets leave your hands free to be where they need to be most - on the job and not fiddling with your welding helmet.

Best of all your electrode pavements becomes accurate reducing all the grinding and reworking. Plus, your view is super-clear.

But how does it work?

The 3 Steps of 3M Welding Hemet Filters

Three main elements in collaboration are what constitute the superior protection in auto-darkening lens (ADL)  filtration technology.

  1. Ultra-Violet (UV)/ Infra-Red (IR) Radiation Filters
    Made from 5 silver, 6 aluminium oxide layers and a thin glass substrate absorbs a pleasing 99.9% of the radiation within the ADL range of shade.
  2. Polarisation FiltersThe UV is filtered out to an exact 99.99997% with the help of polarisation filters. Placed in the perpendicular, the polariser nearest the UV/IR filter at an angle of 90 degrees they are at their darkest.
  3. Liquid Crystal Cells (LCC)Stimulated by the use of electricity, it becomes possible to bend light. Flat-lying LLC’s twist light by 90 degrees.

In the automation application, the LLCs also work to untwist the polarised light waves, which means the lens drops to shade 3 light before striking an arc. However within an astounding 0.1 of a millisecond of an arc being struck the LLC’s activate and the lens becomes dark. When the welding stops, they return to clear status.

Aren’t science and technology fascinating? Just remember, human nature doesn’t change much; we are still left with human error. So, by all means, don your high-tech auto-darkening welding helmets, but diligence, care, and best practice remain non-negotiable.

Contact the Steelmor team for welding requirements, questions, and projects.

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