The term LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers can be designed to deliver a large amount of energy to a very small area. In laser welding and laser cutting operations, this energy can heat metals quickly to very high temperatures. Much of the radiation that strikes the workpiece can be reflected into the environment, creating hazards. Mostly laser light used in laser welding equipment is invisible for the human eye (INFRARED-A), so the hazard may not be readily apparent.

One aspect to remember about laser welding safety is the variety of hazards associated with the systems which are also prevalent in many other forms of equipment. Basic safety training should mean workers are already familiar with some of these issues, but employers should be aware of:

• intense visible and invisible light
• Compressed gasses
• Intense radio frequency energy

Let’s take a look at each of these individually:

• Some pulsed lasers also utilize a flowing gas design, which requires connection to a cylinder of compressed gas. Most of the gases used for laser systems are extremely safe, though since pressurized cylinders can pose a risk, their transportation and usage should occur only when the cylinders are properly restrained.
• As for radio frequency energy, severe burns can result from the improper servicing of units which use RF generators, such as sealed lasers. Anyone servicing such units should be trained in the unit’s safety procedures, and the connections for RF energy should not be touched during operation.

Light Hazards

Due to the laser engraving safety checks in place for welding systems, units are designed in such a way to prevent operators from coming into direct contact with the laser beam.

One of the issues that can arise, however, involves unintentional reflected light, which falls into the following categories:

• Diffuse Reflections – This type of reflection occurs when a reflective surface’s irregularities create a scattering of light in all directions. Of the types of reflections, this is the safer of the two since energy is being divided in many directions and weakened.
• Specular Reflections – This type of reflection is produced in a way that is more mirror-like, recreating close to 100% of the original light compared to the scattered light of diffuse reflections. Though there is a higher danger associated with this form, it is much less common and laser welding systems are often designed to eliminate specular reflective surfaces that would come across the beam’s path.

With proper safety procedures in place, and by following guidelines which accompany your laser welding systems, these hazards should be greatly minimized.

Skin and Eye Hazards

Due to laser engraving safety checks in place, the effects of lasers on skin are usually considered of secondary importance. Compared to laser welding and engraving systems, high-powered infrared lasers utilized in applications for welding and cutting pose a much greater risk of injury.

Some potential effects that can occur if safety procedures are not followed include mild reddening, blistering, and charring, all of which are usually reversible or repairable. Other potential issues could include ulceration, scarring of the skin, depigmentation and damage to underlying organs.

In regards to eye safety, some forms of laser beams operate at a wavelength which if exposed to the eye can pass beyond to the retina. With no pain indicators present and the beam being invisible, someone exposed can be unaware at the time of occurrence.

This is just another reason why utilizing industry-standard laser safety glasses is so vital to maintaining a safe and healthy workspace.

Electrical Hazards

An additional hazard that can be posed when using laser systems is that of electrical shocks. Some of the ways shocks can occur is through contact with:

• Exposed utility power utilization
• Device controls
• Power supply conductors operating at potentials of 50+ volts

Operators and service workers for laser welding systems must be especially careful to avoid these dangers by following standard safety protocols. These hazards could be experienced during:

• Set-up and installation
• Maintenance and service
• Troubleshooting, if equipment protective covers are removed

The electrical injuries that can be sustained from improper and haphazard use of laser systems can include everything from a slight tingle to serious bodily injury to death. To avoid accidental contact with these energized conductors, laser welding units utilize a barrier system within the equipment.

Safety Classifications

Depending upon the risk of a specific type of laser, it is graded from Class I to Class IV. Laser welding machines tend to be graded as Class IV lasers, making laser welding safety all the more important.

Two important additional classifications to keep in mind are the Maximum Permissible Exposure (MPE) and Nominal Hazard Zone (NHZ) designations.

• Maximum Permissible Exposure – This is the highest level of laser radiation an individual can be exposed to without receiving harmful physical effects to the eye or skin. Control measures for laser welding systems are in place to ensure any laser radiation emitted falls below the MPE.
• Nominal Hazard Zone – To create conditions for flexibility in laser welding applications, the laser beam of the unit is often not fully enclosed for practicality reasons. In these instances, it is necessary to define an area of potentially hazardous laser radiation, which is the NHZ. Control measures are then put into place for this area to ensure safety during use of the laser system.

Being fully aware of these classifications and their rationales are vital to ensuring proper workplace laser welding safety.