Laser cleaning comes with its own vocabulary. Some of it is physics, some is equipment and some is safety law. If you’re reading a quote, a method statement or a spec sheet, these are the terms you’ll run into.
Short definitions below, grouped by theme. Where we’ve written about a term in more depth, there’s a link.
The process
Laser cleaning
Using laser energy to remove rust, paint, coatings or contamination from a surface. No tool, brush or abrasive touches the surface. Only light reaches it.
→ More in how does laser cleaning actually work.
Ablation
The technical term for removing material from a surface with laser energy. You’ll see it in academic papers and equipment specifications. Laser cleaning is the commercial name for using ablation to remove contamination.
Selective absorption
The reason laser cleaning works. Contamination such as rust and paint absorbs laser energy strongly. A clean surface underneath absorbs much less. So the contamination takes the effect and the substrate largely doesn’t.
Ablation threshold
The energy level at which a material starts to be affected by the laser. Every material has one. Good laser cleaning works in the gap between the threshold of the contamination and the threshold of the surface beneath it.
Thermal shock
One of the ways contamination comes away. The sudden heating makes the contamination expand faster than the surface underneath, which breaks the bond between them.
Fluence
The amount of laser energy delivered to a given area of surface, usually per pulse. It’s one of the main things an operator controls.
Plume
The cloud of dust, particles and vapour given off as contamination is removed. It has to be captured, because it can contain whatever the coating contained.
The equipment
Fibre laser
The most common type of laser source used for industrial cleaning. The laser light is generated inside an optical fibre and delivered to the cleaning head.
Source
The part of the machine that generates the laser beam. It’s the most expensive component.
Cleaning head
The part the operator holds, or the part mounted in an automated system. It directs the beam onto the surface.
Galvo scanner
The mechanism inside the head that moves the beam rapidly across the surface. It uses small motor-driven mirrors. When people say their machine has “stopped producing a pattern”, this is usually where the fault sits.
→ More in laser cleaner repairs and common faults.
Protective window
The replaceable glass in front of the lens. It takes the debris from everything you clean and needs checking and replacing routinely. A dirty window is the most common reason a machine performs worse than it used to.
Pulsed laser
A laser that delivers its energy in extremely short bursts with gaps in between. Most industrial cleaning lasers work this way. The short pulses limit how much heat spreads into the surface underneath.
Continuous wave (CW) laser
A laser that delivers a constant beam rather than pulses. It behaves differently from a pulsed laser, generally trading some control for speed.
Wavelength
The colour of the laser light, measured in nanometres. Most fibre cleaning lasers work at around 1064nm, which is infrared and invisible to the human eye.
Extraction
The system that captures the plume. Sometimes called LEV, short for local exhaust ventilation.
Safety and regulation
Class 4 laser
The highest laser hazard classification. Industrial laser cleaners are Class 4. They can cause eye injury from direct exposure and from reflections, they can burn skin and they can ignite materials.
Specular and diffuse reflection
Two ways a beam can bounce off a surface. A specular reflection comes off a shiny surface like a mirror and stays concentrated. A diffuse reflection scatters off a rougher surface. With a Class 4 laser, both can be hazardous.
Controlled area
The area set up around laser work where access is restricted and safety measures are in place. Nobody enters it without the right protection and authorisation.
Exclusion zone
The boundary around the controlled area that keeps people who aren’t involved in the work at a safe distance.
Laser safety eyewear
Eyewear rated for the specific wavelength and power of the laser in use. It has to match the laser. General safety glasses offer no protection.
Laser Safety Officer
The person responsible for laser safety on a job or in an organisation. In UK guidance the roles are often called the Laser Protection Adviser, usually an external specialist, and the Laser Protection Supervisor, who oversees safety day to day.
AOR Regulations
Short for the Control of Artificial Optical Radiation at Work Regulations 2010. The main UK law covering the use of lasers at work, including the duty to assess risk and to train the people using them.
PUWER and COSHH
Two other sets of UK regulations that apply to laser cleaning. PUWER covers work equipment and the training needed to use it. COSHH covers hazardous substances, which includes the fume given off when you remove coatings like lead paint.
Surfaces and results
Substrate
The material underneath the contamination. The thing you want to keep.
Surface profile
The microscopic texture of a surface. It matters when a surface is being prepared for a new coating, because the coating needs something to key into.
Proof of concept assessment
How every LaserTec job begins. We assess the surface and the contamination, then confirm the right approach before the work starts. On straightforward steel it’s quick. On historic stone or delicate timber it decides whether the job goes ahead.
Test panel
A small area cleaned and documented on heritage or historic work, so the result can be assessed before the full job is approved. Conservation officers will often ask to see one.
→ More in laser cleaning carved stonework.
Line of sight
A laser can only clean what the beam can reach directly. Deep cavities and hidden faces are difficult for that reason.
→ More in the limitations of laser cleaning.
A last word on the vocabulary
Knowing the terms helps you read a quote or ask the right questions. It doesn’t replace the experience of the person holding the laser. Two operators with the same machine produce different results on the same surface, which is why laser cleaning is a specialist trade.
→ More on choosing between subcontracting, hire and buying.
Got a job you’d like us to look at? Get in touch with our team and tell us about it.
