Gaussian vs Top-Hat: What Beam Shape Does to Your Surface
Two lasers with the same wattage can leave very different surfaces behind. One reason is beam shape: how the energy is spread across the spot that hits the work.
A Gaussian beam is strongest in the centre and fades toward the edges. A top-hat beam is closer to flat across the spot, with a sharp edge. Netalux uses both, and the shape is one of the biggest differences between its machines.
Why shape matters more than most buyers expect
Most conversations start with power: 150 W, 300 W, 1000 W. That tells you how much energy the laser delivers over time. It doesn't tell you how concentrated that energy is when it lands, or how evenly it's spread.
Laser cleaning works when the contaminant absorbs enough energy to break away while the base material stays within its limits. Shape decides where that energy lands within each spot. The scan pattern then decides how those spots overlap across the surface. Both matter, and neither shows up in a wattage number.
Gaussian: focused and controllable
Picture a smooth hill. The middle of the spot carries the most energy and the edges carry less. That concentration gives the operator very precise control, which makes Gaussian beams the natural choice for welds, edges, small features and selective removal.
The Needle family is Gaussian: up to 1 mJ per pulse on the 100 and 150, and up to 2 mJ on the 200 and 300.
Two things to keep in mind. A concentrated peak can mark a sensitive surface even at modest power, so settings matter. And on a broad, flat surface the overlap between passes becomes important. Too little leaves stripes, and too much reheats the same strip. Neither is a flaw in the beam. It's part of dialing in the process.
Top-hat: even coverage
Now picture a mesa: flat across the top with steep sides. Energy is spread more evenly across the spot, so each pass clears a wide, consistent track. On a large coated surface, that evenness is what lets you move fast without leaving stripes or overheating the middle of each pass.
Jango is the top-hat machine, delivering up to 100 mJ per pulse in a water-cooled industrial package. It's built for tanks, structural steel, large fabrications and heavy coatings, where coverage is the whole game.
Even energy doesn't mean the surface can't overheat. Energy per area, travel speed and repeated passes still decide what happens to the substrate.
Kamino: the space in between
Kamino 300 sits deliberately between the two. Its 10 mJ pulses are delivered with a profile that combines the control of the Needle's Gaussian beam with the throughput and softer touch of the Jango's top-hat. In practice, that means it can work detail and still clear open surfaces efficiently.
That makes Kamino a good fit for jobs that move back and forth: coating removal on complex parts, recurring maintenance on machinery, or anything where you'd otherwise want two machines.
Dagger: both shapes in one beam
Dagger 4000 takes a different route entirely. It's a continuous-wave laser with a 1000 W Gaussian core inside a 3000 W top-hat ring, and the operator can fire either one or both together.
That's what lets Dagger strip a coating and condition the steel underneath in the same process. One part of the beam handles removal and the other shapes the surface, giving you a cleaned surface with a measurable anchor profile ready for recoating.
Because Dagger is continuous rather than pulsed, it puts heat into the work differently than the other three. That's an advantage when you want to change the surface, and something to test carefully on thin or heat-sensitive parts.
Shape, pulse and mode are three different things
These terms get mixed up, so here they are side by side:
Beam shape (Gaussian, top-hat): how energy is spread across the spot.
Pulse characteristics (pulse energy, length, frequency): how energy is delivered over time.
Operating mode (pulsed or continuous-wave): whether energy arrives in short bursts or a steady stream.
Needle, Kamino and Jango are pulsed. Dagger is continuous-wave. None of them is automatically gentle or harsh. The result depends on how all three factors combine with your material.
Which Netalux model?
Your surface needs | Test first | Beam | What to check |
Welds, edges, fine detail | Needle | Gaussian, pulsed | Edge control, local heat |
Detail plus open areas | Kamino 300 | Between Gaussian and top-hat, 10 mJ | Finish and consistency across both |
Large coated areas | Jango | Top-hat, pulsed, up to 100 mJ | Throughput, overlap between tracks |
Removal plus anchor profile | Dagger 4000 | Gaussian core + top-hat ring, CW | Measured profile, heat effects |
How we compare beams on your part
We prepare several identical areas from the same part or batch and agree on what "clean" means before we start. Then we run each machine, record the settings, distance and number of passes, and judge every patch the same way: magnification, residue checks, roughness readings, or whatever test your process actually uses.
We count the whole job, not just laser time. A wide beam that needs edge touch-ups can lose its speed advantage. A precise beam that excels on detail can lag on open surfaces. The finished part tells you more than the beam diagram.
Limits
Beam shape alone doesn't guarantee coating removal, low heat or zero damage. Shiny metals, layered coatings, unusual pigments, thin parts and heat-sensitive materials can all behave differently from the sample that looked great. Any beam profile graphic we show is a simplified illustration, not a lab measurement.
Safety
All four machines are Class 4 lasers. Plan for direct and reflected beams, especially around shiny metal, and use eyewear rated for 1064 nm, a controlled work area, trained operators and effective fume extraction. Some coatings need additional respiratory or fire controls, so assess the coating as well as the laser.
See our laser safety equipment, training and CCOHS's laser guidance.
Frequently asked questions
Does a top-hat beam always clean faster?
On large, even coatings it usually covers ground faster. On detailed parts it can lose that advantage. The coating, finish and geometry decide.
Is Kamino Gaussian or top-hat?
It's in between by design: Gaussian-style control with more of the coverage and softer touch of a top-hat.
Does an even beam mean no heat damage?
No. Energy per area, speed and repeated passes still matter.
Where does Dagger fit?
Dagger combines both shapes: a Gaussian core and a top-hat ring, run separately or together, in a continuous-wave laser.
How do I choose?
Send us a sample and tell us what "clean" means for that part. Book a demo or call +1 (705) 805-2737.
