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Safety First: Your Guide to Using a Laser Engraving Machine Safely

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Laser engraving offers so many benefits for a large number of industries, such as automotive, aerospace and medicine and thanks to systems such as the N-Lase series, a flexible range of options has enabled laser technology and its benefits to be more accessible than ever.

Nonetheless, the ability of lasers to engrave different materials comes with a number of risks to safety that must be considered carefully when purchasing and using a laser engraving machine. In this blog, we provide you with a guide to using laser safely.

 

LAsers - what are the hazards?

 

 

Laser Safety Glasses

The type of hazard posed by a laser system depends on its power and its wavelength (colour). For example, one of the greatest hazards is normally to the eyes. Fiber lasers present one of the highest hazards of any laser because the light is transmitted to the back of the eye but is not visible, meaning that the usual protective responses we have such as blinking or looking away won't help in the way we think they might. In fact, light entering the eye in this way can cause permanent damage to our retina, resulting in a blind spot - or worse still, damage to the optic nerve. Long term exposure to 1µm radiation can also cause cateracts on the cornea of the eye.

It is important to always observe the correct procedures. That being said, we don't mean to scare you - as long as the correct procedures are followed, laser marking machines are safe to use. So, always consult your manufacturers guidance, and always wear your laser safety goggles!

The light from the laser engraving machines can also burn skin and anything else that gets in its way. The laser beam or any scattered light close to the point of scatter can cause skin burns and set fire to flammable substances such as wood, paper or plastics. The beam path is deliberately enclosed to prevent human access to the beam, as well as being there to prevent dust or other airborne debris from contaminating the optics which could permanently damage the laser. All of the removable guards should have interlocks attached to them which need to be activated to ensure they are in place whenever the laser is active. This ensures that the beam path will not come into contact with any surfaces it can damage, such as skin, clothes or workspaces.

Laser Beam Caution Yellow Sign


In addition to the potential hazards for our skin and eyes, lasers pose some 'collateral hazards' that we might not automatically think of, but that still can cause us serious safety concerns if not considered and addressed:

Thermal Hazards

Laser welding, marking and heating are all thermal processes, so they can cause a flame at the surface where the laser is being applied. The process can also generate fine particles which, if they accumulate, can become flammable. Therefore a fume extraction system and a gas cross flow curtain may be necessary. If this is a safety concern, then it may be necessary that a gas curtain and fume extraction be installated and maintained to mitigate this hazard.

Fumes

Cutting and marking processes melt and vapourize the part creating potentially toxic or inflammable fumes. This would be another reason to consider the installation of a fume extraction system.

Electrical

The systems contain mains (230Vac) circuits. These circuits are all fully contained and insulated. These potentially hazardous circuits must be correctly maintained to avoid the risk of electrocution.

Pneumatic pressure

Some lasers use a compressed air supply to assist the laser process, for cooling or as a method to move parts using a pneumatic cylinder. Compressed air supplies must be correctly used and maintained to avoid risk of explosion or air injection through the skin which can be fatal.

 

Laser Safety Classes

 

International safety standards have developed a laser class system which corresponds to the degree of the risks posed by each laser. The European standard is EN60825-1, using Classes 1 to 4. The American standard is ANSI Z136.1 and essentially follows the same principles.

For example, the laser engraving machines that Needham Laser Technologies manufacture are Class 4 lasers BUT can be treated as Class 1 because suitable safety systems and precautions have been implemented.

Here is a summary of the classes:

Class 1

Lasers which are safe under reasonably foreseeable conditions of operation, even when exposure occurs while using optical viewing instruments (eye loupes or binoculars).

Class I also includes high power lasers that are fully enclosed so that no potentially hazardous radiation is accessible during use.

Class 2

Lasers emitting visible radiation in the wavelength range from 400nm to 700nm. Eye protection is normally afforded by aversion responses including the blink reflex. but can be hazardous for deliberate staring into the beam. The time base of 0.25 s is assumed

Class 2M

Laser products that emit visible laser beams and are safe for short time exposure only for the naked (unaided eye). Eye injury may occur following exposure using optical viewing instruments such as eye loupes or binoculars.

Class 3R

Laser products  where the risk of injury in most cases is relatively low because the exposure level could cause injury but injury is unlikely. The risk of injury increases with exposure duration and exposure is hazardous for deliberate ocular exposure

Class 3B

Direct intra-beam viewing of these lasers is always hazardous. Viewing diffuse reflections is normally safe. Class 3B lasers may produce minor skin injuries or even pose a risk of igniting flammable materials. However, this is only likely if the beam has a small diameter or is focused.

Class 4

Lasers which are also capable of producing hazardous diffuse reflections. They may cause skin injuries and could also constitute a fire hazard. Their use requires extreme caution.

 

Laser Safety Officers

 

A laser safety officer (LSO) is an individual designated by a company, university or governmental institution, who has the responsibility to monitor the safe usage of lasers in a work environment by defining the proper control measures according to the different levels of laser hazards.

This person also has the authorisation to enforce these measures in the work environment effect, thanks to his/her knowledgeable evaluation and control of said laser hazards. For all class 4 lasers, the appointment of an LSO is mandatory to ensure that safety procedures are adhered to at all times. 

The duties of an LSO include:

  • Coordinating the acquisition of laser devices or laser systems throughout the company.

  • Keeping records of accidents and reporting them.

  • Coordinating and assuring compliance of all lasers with standards.

  • Carrying out periodic safety inspections of laser areas and laser devices.

  • Recommending necessary changes in safety rules, regulations and procedures as laser technology develops.

  • Providing basic training, educational material and proficiency tests for personnel working with lasers.

  • Supervising the educational and enforcement aspects of Standard Operating Procedure (SOP).

  • Authorising personnel to use lasers or laser systems, after a basic safety training course.

  • Inspecting and approve laser facilities before laser operation begins.

  • Implementing appropriate engineering control, administrative control, personal protective equipment.

  • Reviewing and approving the SOP.

  • Maintaining up-to-date inventory of all lasers in the company.

  • Participating in accident investigations involving lasers.

  • Writing and updating a Laser Safety Manual.

 

CONCLUSION

 

Laser technology is so exciting, and can bring a whole host of benefits to businesses in a wide variety of sectors. That being said, it's powerful technology that does not come without safety risks. Here are some do's or dont's to consider buying and using a laser marking system:

Do:

  • Familiarize yourself with the SOP and safety procedures associated with the laser system.

  • Report any changes or potential hazards of the system to the LSO.

  • Check the guards are all in place and not damaged or displaced.

  • Correctly fit the beam tubes and ensure that the interlocks are in place before using the laser system.

  • Wear necessary PPE when directed to do so by the SOP or when conducting service operations on the system.

Don’t:

  • Use the laser system without the correct training or permissions.

  • Displace or damage any of the guarding or guard panels of the system.

  • Expose yourself to laser radiation within the hazard zone defined by the guarding of the system.

  • Interfere with the control circuits or their safety circuits without training and the correct system documentation.

 

If you'd like to learn more about the laser engraving systems we have to offer, visit our website.