Laser welding fuses metal with a focused beam of coherent light — millisecond melts, micron precision, and heat so contained it barely touches the part around the seam. The fastest-growing process in modern fabrication.
A laser delivers a concentrated beam of light — usually through an optical fiber — that is focused to a spot under a millimeter wide. That spot can carry enough energy density to melt or vaporize steel instantly. The heat input is so localized that welds are narrow, fast, and leave a heat-affected zone measured in tenths of a millimeter.
Two modes matter. Conduction mode melts the surface into a shallow, smooth bead — thin sheet, cosmetics, and joints that must stay thin. Keyhole mode vaporizes a capillary channel that lets the beam reach deep into the material — the mode that welds 1/4 in steel in one pass faster than any arc process.
Fiber laser, argon shielding — tune from here per material.
| Material | Power | Speed | Focus | Mode |
|---|---|---|---|---|
| 0.5 mm steel | 0.5–1 kW | 4–8 m/min | Surface | Conduction |
| 1 mm steel | 1–1.5 kW | 3–6 m/min | Surface | Conduction |
| 2 mm steel | 1.5–2.5 kW | 2–4 m/min | +0.5 mm | Keyhole |
| 1/8 in steel | 3–4 kW | 1–2 m/min | +1 mm | Keyhole |
| 1/4 in steel | 4–6 kW | 0.7–1.2 m/min | +1.5 mm | Keyhole |
| 1 mm aluminum | 2–3 kW | 3–5 m/min | Surface | Keyhole |
| Property | Conduction | Keyhole |
|---|---|---|
| Bead shape | Wide, shallow | Narrow, deep |
| Penetration | Under 1 mm | To 25 mm+ |
| Speed | Fast | Very fast |
| Cosmetics | Smooth top bead | Finer, harder to control |
| Thickness range | 0.1–1 mm | 0.5 mm and up |
Fiber lasers from 1–8 kW cover sheet to plate. Higher power buys speed and depth, not just capability.
Browse power sources →Fixed optics for simple seams; scanner heads move the beam with mirrors for speed and patterns.
Armored fiber with connectors and protective optics — the beam path from source to head.
Six-axis robots or gantries move the head at welding speeds — accuracy is the whole game.
Browse automation →Class 4 beam containment — certified housing, interlocks, and beam-blocking curtains.
Argon or nitrogen through the nozzle — flow is low but the seam needs full coverage.
Lasers reject serious heat — process cooling water keeps source and optics at temperature.
Wavelength-rated goggles or full beam-safe viewing — ordinary hoods do nothing against a laser.
Browse PPE →The beam doesn't care about gravity the way an arc does — laser welds in every position with the right beam and gas setup.
The easiest and fastest — full speed, cleanest keyhole, ideal for production seams.
Fine with conduction mode; keyhole needs a slight beam tilt so the puddle can't run.
Works — gravity pulls the keyhole molten wall down, so power and speed get retuned.
Robots weld tubes and structures in any attitude — position is just another program.
The laser's real tricks are in how the beam moves — power, speed, and path programming.
No filler — melt the two edges into one. The fastest, cleanest laser weld there is.
Scan the beam in a circle or figure-eight to widen the bead and stabilize the keyhole.
A scanner moves the beam between joints without the head moving — spot-weld many locations at speed.
A MIG arc rides behind the beam — deep keyhole plus filler tolerance for gapier joints.
Short pulses limit heat for spot welds and fine features — the battery and electronics favorite.
Cold-wire feed bridges gaps and adds alloy — the fix for fit-up problems and crack-prone alloys.
Laser welds are narrow — defects hide inside. Read the bead, then validate with inspection.
Appearance
Pin holes or internal bubbles — gas trapped in the fast-freezing weld.
Causes
Dirty metal, oil, poor gas coverage, or keyhole collapse.
Prevention
Clean, shield, and keep power/speed in the stable window.
Appearance
Cracks along the bead — aluminum and high-sulfur steel are prone.
Causes
Fast freeze plus an unfavorable alloy composition.
Prevention
Filler with crack-resistant chemistry or beam oscillation.
Appearance
Grooves along the bead edge — the fast puddle didn't refill the toe.
Causes
Power too high or speed too fast for the bead width.
Prevention
Balance power and speed; oscillate to widen the fill.
Appearance
Ridged, uneven crown — the puddle couldn't flow flat at speed.
Causes
Travel speed beyond the stable range for the power.
Prevention
Slow down or raise power to flatten the bead.
Appearance
A shiny bead on top, cold root below — the classic hidden failure.
Causes
Power too low, focus wrong, or travel too fast.
Prevention
Tune power, focus, and speed; verify with sectioning.
Appearance
Metal droplets beside the seam — keyhole instability.
Causes
Power spikes or an unstable keyhole wall.
Prevention
Stable power, consistent speed, clean optics.
Appearance
A hollow sag on the root side — the weld dropped through.
Causes
Gap too wide or keyhole too big for the joint.
Prevention
Tighter fit-up, backing, or lower power at the root.
Appearance
Discolored, scaly bead — the hot seam saw air.
Causes
No or poor shielding gas coverage.
Prevention
Right gas, right flow, nozzle close to the seam.
The documents behind laser welding quality, safety, and qualification.
| Standard | Covers |
|---|---|
| AWS D17.1 | Fusion welding of aerospace hardware — laser included |
| ISO 13919 | Acceptance levels for laser and electron beam welds |
| ISO 15614-11 | Qualification of laser welding procedures |
| ASME Section IX | Qualification for pressure equipment, laser allowed |
| IEC 60825-1 | Laser product safety — the Class 4 rules |
| ISO 18278-1 | Resistance welding — not laser, but the quality cousin |
| ANSI Z136.1 | Safe use of lasers in the workplace |
| AWS B2.1 | Procedure qualification of welding processes |
All-in-one machine settings helper for a fast laser starting point.
Power ÷ speed — the number that controls penetration and distortion.
Set shielding flow and read the gas usage your laser cell needs.
Match wire to base metal when laser work needs filler at all.
What power and focus fit foil vs 1/4 in plate.
See keyhole mode and handheld laser technique on real metal.
Watch the technique sections — keyhole mode, beam oscillation, and handheld scanning — on real metal.
Watch VideosA shop-floor cheat sheet with the parameter table, mode chart, and gas quick reference.
Download from Library