Top 5 laser engraving mistakes.

Skin burnt by laser engraving machine

We all make mistakes every now and then, it’s only human after all. But how can we avoid and adapt to prevent these mistakes from happening in the first place?

We have decided to write this article to try and help highlight and educate end users of the top 5 mistakes commonly made by both hobbyist users and professionals.

A number of dangers are apparent when maintaining and operating a laser engraving / cutting machine.

Number 1 : Burns

Getting burnt by your own laser is never enjoyable, its something you never want to happen. It can easily be avoided and tends to only happen due to incorrect usage of the machines safety functions.

When performing alignment of the mirrors users tend to defeat or override the safety circuit in the belief that it will make the task quicker and or easier.

Overriding and disabling the safety system is something you should never do, or have to for that matter. It’s been fitted for a reason.

It’s super easy to open the lid and make adjustments, and close the lid before pulsing. Sure it might add a couple seconds to the task at hand, but what price can you put on your own safety?

Number 2 : Fires

Lasers are dangerous, we all know that. But what are some of the dangers a user becomes complacent with?

The laser works by burning, we are relying on the focused spot performing the burn to continue moving and never stay in the same place too long to prevent a fire.

Lasers take time to complete a job, a complacent user might be tempted to turn their back on the machine and return to a finished work piece.

Never allow a laser to run without supervision, even if it is just to take a toilet break. I can guarantee this will be the time a failure occurs and a fire breaks out.

Some common causes of a laser fire:

  • stepper motors failing, this causes the beam to stop moving and fire in the same spot.
  • Air assist failure, you are more likely to have a fire if you don’t have a continuous airflow to extinguish small flair ups.
  • Jam up, when cutting a piece can easily pop itself up, next time the head passes its possible that it will cause a jam up.
Laser engraving machine fire
Laser engraving machine fire
Laser engraving machine fire
Laser engraving machine fire

Number 3 : Damaged optics

Damaged to mirrors and lens will reduce the reflectivity of mirror or the transmission of the lens resulting in power loss. Secondary problems are caused by the mirror or lens absorbing the laser energy, this causes the optics to heat up. In extreme cases this can cause them to distort, warp or even crack.

The common causes of damaged optics are :

  • Forgetting to turn the air assist on, whist the air assist is running the lens will be surrounded by clean air at a positive pressure, this prevents the smoke created by liaising from reaching the lens.
  • Forgetting to turn on the extraction, this will cause smoke levels to build up inside the machine, fouling the mirrors and optics.
  • Incorrect cleaning leading to scratches or burnt marks.

We have a handy guide to help you keep your mirrors and lens clean.
Cleaning laser engraver mirrors & lens

co2 laser lense damage

Example of mirror and lense powerloss

Example of mirror and lense power loss

Number 4 : Incorrect focal length

Having the focus length / height set incorrectly will not only lead to reduced engraving quality, but also require elevated power levels to complete the same job as a machine set with the correct focal length.

The lens fitted to your machine has a specific focal length, this is a distance from the lens center to the workpiece at which the beam is most focused. Most commonly the machine will ship with a f50.8mm lens, this means your workiece should be 50.8mm from the lens.

You can find out your focal length by performing a ramp test, this test involves cutting a number of lines into a sloped piece of acrylic or wood, the beam profile can be viewed to see at what distance the lens was most effective.

We have a handy blog post that explains all the different available focal length lens and the effect they have on your work output.
CO2 Laser Lens Focus Length Explained


Number 5 : Electrocution

China are not known for high standards of wiring, they will skimp and save wherever they can, wiring and safety is not a priority for the manufacturers.
Wiring is commonly of the incorrect type of rating for the load and type of equipment.

The risk of electrocution can be minimised by following these steps:

  • When performing maintenance ensure the machine is unplugged and allow a few minutes for any stored electrical potential to discharge.
  • Never defeat safety circuits
  • Do not enter any enclosed area of the machine whilst it is powered on.
  • Always consult a qualified electrician with any queries, do not perform any maintenance you are not competent with.
  • Ensure your machine is correctly grounded, and is using the correct type of grounding system for your country or locality.
  • If you are unsure, pause, think and ask.

That electrical arc you see  inside the laser tube is between 22,000-34,000v and up to 40ma of current, now if you was to become the path of least resistance or you happened to touch the machine whilst this arc occurred say ie with your left hand. The path of least resistance would follow your arteries and through your heart, stopping your heart resulting in death.

risk of electrocution

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