Key takeaways
- Pulses last a few billionths of a second, so heat does not reach the base metal.
- Contaminants absorb the light far better than clean metal, which is why the beam removes them and then stops.
- Pulse width, pulse energy and frequency decide how gentle or how aggressive a pass is.
- Always test a new material on an offcut before you clean the real part.
How a pulse removes a contaminant
A pulse laser cleaner releases its energy in very short bursts, each lasting a few billionths of a second, thousands of times per second. Rust, paint, oil and oxide absorb this light far more readily than clean metal. The contaminant heats up in an instant, expands and breaks away from the surface, partly as vapour and partly as fine particles that the fume extractor collects.
The short burst is what protects your part. Each pulse ends before the heat has time to travel into the metal underneath, so the base material stays close to room temperature. Hardness, flatness and plating stay as they were. No grit is pressed into the surface and no chemicals touch it, which also removes the risk of hydrogen embrittlement on high-strength steel.
Why the cleaning speed depends on the layer
The same principle explains the cleaning speed. Each pulse lifts only a very thin layer, so a light film of rust clears in one pass while a thick crust needs several. Damage to the part appears only when the power is set too high or the beam stays on one spot too long, so test any new material on an offcut first.
The settings that shape the result
Four settings do most of the work. They are the same ones listed on every datasheet, and each changes something you can see on the part. Exact values vary by model.
| Setting | Typical range in our collection | What it changes on your part |
|---|---|---|
| Wavelength | 1064 nm | Well absorbed by metals and most coatings. |
| Pulse width | 2-500 ns | Controls heat input. Shorter pulses protect thin or heat-sensitive substrates. |
| Single pulse energy | 0.8-15 mJ | Decides whether a thick layer breaks in one pass or several. |
| Frequency | 1-4,000 kHz | Governs pulse overlap and how even the finished surface looks. |
Because these machines use a MOPA pulsed fiber source, pulse width can be tuned independently of the other settings. That is what makes selective cleaning possible: you can take off a topcoat and leave the primer, or remove oxide and keep the plating.
What this means at the workbench
Your operator does not need to understand the physics to get a good result, but they do need a routine. The steps below are the sequence we recommend for any new part.
Test on an offcut
Start with the lowest power that moves the contaminant and note the settings.
Raise energy only as needed
Increase power or pulse energy in small steps until the layer lifts in a sensible number of passes.
Keep the beam moving
Overlap lines evenly and never hold the beam on one spot.
Save the recipe
Record the working parameters so every operator and every shift repeats the same finish.
A pulse laser cleaner is a Class 4 laser. Use eyewear rated for 1064 nm, run fume extraction and follow your site safety rules.
Before you start a job
- Identify the contaminant and the substrate.
- Confirm fume extraction is running.
- Wear eyewear matched to the 1064 nm wavelength.
- Test on an offcut or a hidden area and inspect the result.
- Save the parameters that worked.
Common mistakes that spoil the result
- Too much power too soon. Raising power to save time is the fastest way to mark a part. Raise it in small steps instead.
- Holding the beam still. Heat builds up where the beam dwells. Keep it moving with even overlap.
- Skipping the test. Two parts that look the same can behave differently because of the alloy, the paint or the age of the rust.
- Ignoring the dust. The removed material has to go somewhere. Without extraction it settles on the part and on the lens.
Pulsed versus continuous output
A continuous wave laser delivers a steady beam, so energy keeps flowing into the surface and heat has time to spread. A pulsed laser packs the same average power into brief, intense bursts. The peak power in each burst is high enough to lift a contaminant, while the long gaps between bursts let the surface cool. That is why pulsed machines are the usual choice for thin sheet, mould surfaces and any job where a coating must be kept.
It also explains why two machines with the same average power can behave differently. What counts for the finish is how that power is delivered: pulse width, pulse energy and frequency.
Why the same part can need different settings
Settings follow the contaminant as well as the metal. A thin oil film, a layer of paint and a hard oxide scale absorb light differently and break away differently. Treat each combination as its own recipe.
Frequently asked questions
Does the laser heat the whole part?
Not in normal use. Each pulse is so short that most of the heat leaves with the removed layer, and the base metal stays close to room temperature. Heat builds up only if the power is too high or the beam stays on one spot.
Why does the laser remove rust but not the steel?
Rust, paint and oxide absorb the 1064 nm light far more readily than clean metal. Once the contaminant is gone, the surface reflects more of the beam and the cleaning effect drops. That is why the process is self-limiting when settings are right.
Is one pass always enough?
No. A thin film may clear in one pass, but a thick crust needs several, because each pulse lifts only a very thin layer.
Can I use the same settings on every part?
Use them as a starting point only. Save a recipe for each part and material, and test on an offcut when something changes.
Next step: not sure which power class fits your material? Read the selection guide, or send us a sample and we will run a remote test.
