The Auto-Darkening Helmet
One of the more profound and game-changing developments in welding technology has been the auto-darkening helmet. So what are auto-darkening welding helmets and should you get one?
Safety is critical when welding and your helmet is one of the most important parts of your equipment. The arc created when welding is incredibly bright and gives off radiation across a broad range of the electromagnetic spectrum. A few seconds of direct exposure (without eye protection) will cause “arc eye” or “welder’s eye”, a painful and potentially damaging form of inflammation.
The first welding helmets designed contained a fixed opaque glass to protect the users eyes from this radiation. This glass is very effective while welding but almost impossible to see through while positioning your electrode or welding gun. Subsequent designs used a flip mechanism allowing the operator to setup with the helmet up and then quickly flip it down with jerk of the neck.
What Is an Auto-Darkening Helmet?
An auto-darkening welding helmet as the same suggests, automatically darkens or lightens its glass when it detects a source of bright light. Initially developed by Hornell International in 1981, the technology was branded ‘SpeedGlas’ (now owend by 3M). The modern auto-darkening helmet is a marvel of engineering housing all its components in a design that’s not much bigger or heavier than traditional helmets.
Why Use Auto-Darkening Helmets?
The answer to this question is simple: protection and convenience. An auto-darkening helmet provides as good or better protection compared to its manually operated cousin. Instead of constantly flipping a helmet up and down (even for small re-positioning), the auto-darkening helmet can remain in place always in front of the operators eyes.
The convenience of always having your helmet in place also means increased productivity. It allows a welder to make fluid transitions between welding and non-welding activities. Users of auto-darkening welding helmets always have their eyes on target and protected whether starting a bead or making adjustments to the welding machine.
How Do Auto-Darkening Helmets Work?
Auto-darkening welding helmets are made up of a number of different components that sense light and react to it. They are designed to darken instantly in milliseconds, and block out a number of different wavelengths of light. As soon as the sensors stop detecting a light source, the lens becomes fully transparent.
They have several different filters and components that engage when exposed to the light from a welding arc or similar bright source.
Ultraviolet and Infra-red Filter
The first is the ultraviolet and infra-red filter. This filter blocks out both types of rays even when the auto-darkening lens isn’t activated. It consists of a very thin layer of glass that is itself made up of five silver layers and six aluminum oxide layers.
These layers filter out the infra-red radiation and protect other parts of the lens from damage. The ultraviolet filter works along with the polarization filter and the metallic filter to protect your eyes from UV radiation.
The Polarization Filter
An auto-darkening helmet actually contains three polarization filters to protect you from UVA radiation. The first of these filters is located behind the ultraviolent and infra-red filter. The other two are located behind the next two layers.
Combined, they protect from the visible light put off by a welding arc. The first polarization filter is set at a 90 degree angle so that it darkens as much as possible.
Liquid Crystals Cells
Behind the first polarization filter and between filters two and three are the liquid crystal cells. These cells actually bend light away from them when exposed to electricity. Light is regulated through the cells by altering the amount of electrical current directed to them. These cells are what actually darken and lighten the most in an auto-darkening helmet.
Sensors
Finally, your helmet contains a number of arc and light sensors. These sensors determine the intensity and brightness of the light coming in. They control the electric currents that are sent to the cells. The more light the sensors pick up, the more electricity is sent to the cells, and the darker they get. Light sensors focus on the amount of light present while Arc sensors detect how intense the light is.
Auto-Darkening Helmets: What to Look for
Both beginners and professionals can benefit from an auto-darkening helmet. They truly make the entire welding process easier and more efficient. Let’s examine some key features to look for before purchasing.
How Light Sensitive Is It?
If the arc and light sensors in the helmet aren’t fairly sensitive, the lens may not darken quickly enough or to the right degree, leaving your eyes unprotected. The better helmets on the market have multiple arc sensors for better detection and response time.
Controls
Most helmets on the market are equipped with several controls for adjustment and customization. High quality helmets give the user fine grained control over:
Light Sensitivity – how much light reaches the welder’s eyes. The user can select different shade levels.
Delay Control – how long the lens will remain dark after an arc is no longer detected. Gives the welder a way setting an ‘adjustment’ period for his/her eyes.
Response Time – how quickly the lens auto-darkens when exposed to an arc. Most are rated in milliseconds and all are certainly faster than flipping down a traditional helmet.
Greater adjustability gives the welder more flexibility when working different lighting conditions or along side other welders.
The Viewing Lens
Helmets that have full coverage lenses are the easiest to use and the most comfortable. A larger viewing lens is also beneficial when not welding as it allows for wide angle views and less eye strain.
A larger lens can also help when performing out-of-position welds or when reaching tricky joints. Most will agree that bigger is better when it comes to lens size.
Power Source
There are a few different ways these helmets are powered. Most are battery powered with user replaceable (or rechargeable) batteries. Battery life indicators are found on high quality models as well. Solar powered models are powered by either natural or artificial light sources.
Conclusion
Auto-darkening helmets may seem like an overly high-tech solution to a problem that has already been solved but its benefits really add up. Purists may swear by traditional flip up helmets but why not keep your eyes where they’re meant to be?
An auto-darkening welding helmet makes the entire process faster and more efficient. The fact that these helmets are quite affordable and offer outstanding protection for your eyes makes them a necessity for every welder’s equipment kit.
