A simple Explanation of Laser Safety Classifications within a Laser Marking or Laser Cutting Machine

Almost all manufacturing equipment has inherent safety risks. For most types of machinery these risks are obvious, easily identifiable through visual or audible inspection.

The laser source within a laser marking or laser cutting machine cannot be monitored by the user visually or audibly without the use of special equipment. Therefore, there are specific safety classifications given to laser devices so that the degree of hazard can be understood and the risks mitigated to avoid accidents.

All laser devices must be labelled to identify the level of laser safety hazard, called the laser safety class.

There are 4 laser safety classes according to the degree of risk with Class 1 being the lowest risk and Class 4 being the highest risk. Within some of these classes are a number of sub-classes specific to the system configuration, in particular the laser wavelength and/or its AEL (Accessible Emission Limit) i.e. the degree of power emitted from the laser and the exposure time before it becomes hazardous.

By far the greatest hazard to the user is the risk of damage to eyesight. This can be permanent or temporary depending on the power and wavelength of the laser as well as the AEL.

Other risks relate to damage to materials biological, for example damage to skin, or non-biological as well as the risk to cause fire and/or explosion when coming in to contact with flammable or combustible materials such as petroleum, flammable gases, etc.

Within a laser marking, laser engraving, or laser cutting machine the laser source at any wavelength is always Class 4. The Class 4 laser hazard can be reduced by the addition of extra safety measures and devices built around the laser source.

Class 1 defines the laser marking machine or laser cutting machine as being of the lowest risk. A Class 1 laser machine can be operated in almost any environment suitable for an electronic device and emits no harmful laser radiation whatsoever.

To meet the requirements of Class 1 the laser hazard must be contained within a 'light tight' enclosure with all access panels being used for general operation interlocked and all service panels being secured with screws, or similar semi permanent fixings, so that opening of the service panels requires the use of a tool.

When an interlocked access panel is open an indicator must show that the system has moved from Class 1 to Class 4 and power to the laser must be removed so as to prevent accidental operation.

Class 2 is essentially the same as Class 1, however, this type of machine incorporates a visible guiding laser at <1mW. Typically this will be a red guiding laser at the 655nm wavelength.

Class 3 is not typically applicable for a laser marking or laser cutting machine and is more commonly found assigned to equipment incorporating a very strong, visible guiding laser typically at 5mW.

Class 4 is the most dangerous of all the laser safety classes. A Class 4 laser marking machine exposes the user to potentially immediate and harmful laser radiation as well as adds risk for damage to materials that can combust and/or explode. Use of a Class 4 laser must be restricted to a specifically designated and appropriately signed area, segregated from the general work area. Operators of Class 4 lasers should be specially trained and advised of the risks as well as wear specifically configured PPE while working in the designated Class 4 area.

In a perfect world only Class 1 or Class 2 laser marking or laser cutting machines would exist but in some circumstances the safety enclosure becomes an obstacle to the process. In such case Class 4 lasers are required, however, a Class 4 laser should never be operated without the owner and user being fully aware of the safety risks and having in place safety measures to prevent unnecessary accidents.

At Lotus Laser Systems we manufacture a wide range laser marking and engraving solutions ideally configured for laser cutting, laser marking and laser engraving all types of materials. Our experts would be happy to recommend which configuration best suits your application.