Better safe than sorry: unmasking dangerous lasers

By Bhalchandra Chorghade, Editor, CNCTimes.com

Carelessly built enclosures, fake safety glass, bridged light barriers - anyone working on the wrong laser is living dangerously. Unfortunately, not all suppliers meet the justifiably high standards for laser safety. This is especially true for solid-state lasers. Incorrectly installed, their radiation can injure eyes, cause blindness and lead to burns. Five characteristics that indicate when a system is laser-safe:

ENCLOSED BEAMS

If the enclosure of a machine has no gaps, it protects against laser beams. This is the case with systems that can be loaded and unloaded outside the machine body, such as 2D laser cutting machines from TRUMPF. This is yet more difficult with punch laser machines - here, more design know-how is required. Operators must be able to load and unload them directly at the work table with the laser cutting head. Automatically raised protective walls are one measure to intercept dangerous radiation. Once the machine has finished its work, they go down again, allowing the operator to approach the machine directly.

HOODS FOR SHIELDING

In order to intercept as much radiation as possible directly at the source, reputable manufacturers rely on additional measures for machines without a closed enclosure. With punch laser machines from TRUMPF, for example, this job is performed by hoods that are placed over the processing heads. On laser tube cutting machines, several layers of strips cover the enclosure of the work area on the unloading side. This curtain is designed to prevent laser light from escaping while the machine guides the tube out of the processing chamber.

LASERS ONLY SEEN THROUGH PROTECTIVE WINDOWS

In many systems, the production process can be monitored through a window. To ensure that the operator remains unharmed, the plastic window must not allow any radiation to pass through. This is not just a matter of the light of the original laser beam. Because while cutting with solid-state lasers, so-called secondary beams in other frequencies can be generated in addition to this infrared cutting beam. For example, ultraviolet (UV) rays can be formed during the processing of metals. The pane must also reliably shield this light. Laser-safe windows can usually be identified by their green color. But be careful: not every pane is automatically safe. In addition to a CE marking, a laser-safe pane also bears other information, such as its protection level.

THE INTERVENTION OF LIGHT BARRIERS AND SENSORS

If a person enters the processing area of a laser cutting or welding system, the machine must stop immediately. The laser beam must be switched off. Light barriers and safety switches should be available for this purpose. The same applies to worn equipment: if the cable that guides the laser light to the cutting head is damaged, sensors automatically switch off the laser. Protective devices take care of this. In addition, sensors in the laser light cable detect whether it is connected to the cutting head without any gaps, so that radiation does not escape anywhere.

THE CLEAN EXTRACTION, FILTERING AND DISPOSAL OF HAZARDOUS SUBSTANCES

Hazardous substances are generated during laser material processing. We are talking about tiny particles and gases. They can damage equipment and are dangerous for people and the environment. For this reason, the machine must be equipped with an extraction system. It captures the hazardous substances and feeds them to a filtration system. Thanks to it, pollutants can be separated from the air and disposed of cleanly.

https://www.trumpf.com/en_IN/newsroom/stories/better-safe-than-sorry-unmasking-dangerous-lasers/

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