What is laser welding?

Aluminium sheet laser welded with lap joint
Laser welded lap joint 0.040"

Does laser welding work on thin materials?

Laser welding works VERY WELL on thin materials.  In fact laser welding is the best welding process for thin materials, ranging from 0.020″ (0.5mm) to quarter inch (6mm).   We even sell pulsed laser welders that work wonderfully on 0.004″ (0.1mm) stainless steel and inconel.  Our pulsed welders are specially designed for pulsed laser welding jewelry, and for mold repairs using very fine 0.3 or 0.4mm wire.

We can easily weld thin materials that MIG and TIG welding cannot.  For example, the image on the left shows a lap weld on 0.040″ (1mm) aluminum, which was welded with full penetration and no distortion.  The welding was done at half an inch per second travel speed, but could be ran faster if desired.  Perfect for sign manufacturers using thin material to fabricate aluminum signs.  The welding power can be reduced to prevent marking or penetration on the back face.

Is laser welding as good as TIG?

Laser welding is as good as TIG welding, and better in every way in our opinion.  We believe laser welding will replace TIG for sheet metal up to a quarter inch thick.  Laser welding has the following advantages over TIG welding:

  • Much faster.  We typically weld at 1/2″ per second, and can run faster.
  • Easier.  Laser welding requires much less skill.  TIG is difficult.
  • Semi-automated.  Laser welding parameters and wire feed control the welding.  Good welds can be repeated time after time.
  • Better appearance.  Laser welding can be smooth, or if required you can generate a “stack of dimes” with pulsed settings.  
  • Stronger.  Laser welding uses a beam 0.004″ wide which inputs the least amount of heat required to make a good weld.  TIG welding uses an arc approximately 1/8″ wide and the slow travel speed excessively heats the metal, annealing it back a “soft” condition, destroying the microstrure.
  • Less distortion.  Laser welding puts in far less heat, and typically has one quarter of the distortion of TIG.
  • Less energy consumption.  We calculated that our laser welders use 18% to 25% of the electrical energy a TIG does, based on an 1/8″ butt weld.  A HUGE saving with very green environmental credentials.
  • Less gas consumption.  Welding at five times the speed uses far less gas, saving cost and once again being “green”.
  • Far lower cost overall.  Add up all of the above savings including less staff and less skilled welders.  Then add on the saving from faster throughput and lower overheads.

The only disadvantage of laser welding is eye safety.  Refer to our laser safety section for full details.

Stainless steel cover with pulsed laser weld stack of dimes
Pulsed laser weld stack of dimes on stainless steel cover
Internal fillet laser weld on 1/8" steel bracket
Broken MIG weld
MIG weld breakage due to lack of penetration and porosity

Is laser welding as strong as MIG?

Laser welding is as strong as MIG, and should be stronger in most cases.  The heat input is less with laser welding, which is why it causes less distortion and staining.  MIG’s extra heat input anneals the metal, reducing its strength compared to laser welding.  The only advantage of MIG is a larger weld fillet, but the metal next to the weld will be weaker than if it was laser welded and that is the key determinant in the real world, in most situations.

The only time we’ve seen laser welding not as strong as we’d like is when welding straight over galvanizing, where the lower heat input didn’t burn the zinc away as much as MIG does.  Turning the laser power up burns off more zinc and increases the strength.  However MIG welding can easily be too cold, which causes weak welds.

Which metals suit laser welding?

Basically all metals suit laser welding.  We have welded stainless steel, mild steel, galvanized steel, aluminum, inconel and vanadium-aluminum alloy.  Titanium and copper are also targets for laser welding.  Stainless and aluminum weld easily with our welders.  Carbon steel and galvanized steel are also easy to weld, albeit the zinc coating causes smoke and sparks.  However laser welding is not well suited to brass because the zinc boils out before the copper in the matrix has melted.  

Our lasers have a high power density which is required for aluminum and copper, but some competing and much more expensive brands do not.  High power density is required to initiate melting of aluminum and copper, which are very reflective to infrared (IR) in the solid state.  By hitting them with high power in one spot a molten pool can be quickly generated, which then absorbs much more IR than the solid metal.  The molten pool then expands and you are welding.  

Laser welding 20 gauge steel with a guide plate
Laser welding 20 gauge steel with a guide plate

Laser beam welding of thick materials

Laser beam welding can weld thick steel sheets up to 1/4″ at high speed in one pass.  This requires a powerful 3000W laser, or a 2000W with high power density such as our G5-3000WC or Lightwelder20.

The carbon steel plate in this image was welded with our 3kW model at close to 1/2″ per second travel speed.

It is false to say that laser welders don’t penetrate.  This may be true if the welder is underpowered, has low power density, or is poorly used.  However a laser welder is basically a laser cutter with a control system to move the beam around in a controlled weaving pattern.  Laser cutters penetrate deeply, and so can our laser welders, which weld up to 6mm aluminum, steel and stainless steel at high speed in one pass.  


1/4" carbon steel laser butt weld
Back face of 1/4" steel plate after laser welding

Is laser welding pulsed or continuous wave?

Laser welding can be done with both pulsed and continuous power.  In general, continuous wave lasers are for thick materials, and pulsed lasers are for doing fine welds in small or thin materials.

Our hand held laser welders are normally used in continuous mode for maximum penetration and a smooth weld finish.  However they can be set to pulsed mode to do weld cleaning or create a “stack of dimes” effect, as shown on the right.

We also supply welding machines which are specifically designed for pulsed welding. These are mold repair laser welders, which are fiber laser based, but can be the cheaper xenon arc flash tube type.  Our jewelry laser welding machines also use pulses for finely controlled welding.

Close up comparison of pulse frequency on 3mm aluminum
Close up comparison of pulse frequency on 3mm aluminum