Laser welding machines

A laser welding machine joins metal with a focused fiber laser beam instead of an electric arc. Handheld units of about 1 to 3 kW suit fabricators welding thin steel, stainless and aluminium with little distortion or grinding, while robotic cells suit repeat production. Most handheld units can also clean rust, paint and weld discolouration with the same beam.

How laser welding works

The fibre source sends the beam through a cable to a welding head, which focuses it to a very small spot; xTool, for example, quotes a spot of 0.1 to 0.3 mm with an energy density over 1 MW/cm². The joint melts in a narrow, deep pool that solidifies almost at once, while a shielding gas protects it from the air. Because the heat stays in a narrow band, the heat-affected zone and distortion are much smaller than with TIG or MIG on the same thin part.

Two features make handheld laser welding practical on real fabrications. Wobble, or beam weaving, oscillates the beam across the seam to widen the weld and bridge small gaps: IPG lists wobble widths up to about 5 mm (0.200 in), and Amada rotates the beam with a weaving lens on its robotic cell. Wire feed adds filler for gaps, fillets and joints that need reinforcement. Makers claim large speed gains over TIG, such as IPG's "4x faster" for its LightWELD, but the real gain depends on joint type, fit-up and finishing. Our laser welding versus TIG and MIG comparison looks at where the claims hold up.

Main machine types

The robotic cell is a different class of investment. The Amada FLW-3000ENSISe M3 puts a six-axis robot on a 3 m linear carriage with a turn-and-tilt positioner inside a guarded cell, and Amada states laser class 1 for the cell when operated in accordance with EN 60825-1. Handheld units, by contrast, are Class 4 lasers used in the open, which changes what the shop must do around them.

How to choose

• Material and thickness. Maximum thickness falls sharply for reflective, conductive metals. IPG's figures for the 2 kW LightWELD 2000 XR reach about 8 mm (0.313 in) in steel and 8.3 mm (0.325 in) in 3 and 5 series aluminium, but about 3.3 mm (0.129 in) in copper. Treat these as upper limits, not everyday settings.
• Cooling and duty. Air-cooled units are lighter and quicker to move. Water-cooled units add a chiller that must be kept clean, topped up and protected from freezing in an unheated space.
• Wire feeder. Check the wire diameters and whether the feeder is built in or separate; DenaliWeld's feeder takes wire up to 2 mm.
• Cleaning. Pre-weld and post-weld cleaning removes oxide, oil and discolouration. IPG lists cleaning widths up to about 15 mm (0.600 in).
• Presets and training. Parameter libraries shorten the learning curve; IPG ships 100 welding and cleaning presets. Welding knowledge still matters for joint design and fit-up.
• Built-in safety. The American Welding Society lists a key switch, an emergency stop and an external interlock connection as basic features, with two-stage triggers and workpiece contact circuits among the further protections described in ISO 11553-1.

What your plant needs: a laser controlled area

This is the part buyers most often underestimate. A handheld laser welder is a Class 4 laser, and IPG's safety guidance warns that eye damage is possible hundreds of feet away. AWS guidance calls for a qualified laser safety officer, a documented safety program and a laser controlled area at each point of use: a light-tight enclosure with laser-blocking panels, an access door with an interlock switch and a laser-on warning sign, with entry limited to trained people. CCOHS points to the same ANSI Z136.1 standard for Class 3B and 4 workplaces.

• Eye and face protection. Ordinary welding helmets and shade lenses do not protect against laser light. Eyewear must be rated for the laser wavelength; IPG specifies optical density 7 or higher covering 1070 nm, worn with a laser welding helmet.
• Barriers. Curtains, panels or walls rated for Class 4 lasers, with mirrors and other shiny surfaces removed or covered.
• Fume. CCOHS notes that stainless fume can contain hexavalent chromium and nickel, and galvanized steel gives off zinc oxide. Use local extraction close to the plume.
• Power and gas. Handheld units run on lower voltages than a 600 V plant bus: IPG lists 220 V input for the LightWELD, and DenaliWeld lists 480 V for its 3 kW unit. Plan a suitable circuit or transformer, as covered in 600 V power for imported machines, plus shielding gas cylinders and a place to store them.
• Approval. A unit without a recognized certification mark must be field evaluated before use in Canada; our CSA certification guide explains how that works.

Running costs and consumables

• Shielding gas and filler wire, the main materials used per metre of weld.
• Protective lenses and nozzles in the welding head, which take spatter and are replaced regularly.
• Electricity and cooling, including chiller maintenance on water-cooled units.
• Safety equipment: rated eyewear, helmets and barrier panels, replaced when damaged.
• Finishing time. The saving often shows up after welding; xTool claims up to 80 percent less grinding time. Measure it on your own parts before relying on it.

Typical applications

Laser welders do their best work on thin stainless and aluminium: enclosures and cabinets, food service and kitchen equipment, railings and architectural metal, signs and displays, ductwork and sheet metal assemblies, and repairs to thin parts where TIG would warp the work. Robotic cells take on repeat assemblies such as brackets, frames and housings, where fixtures hold each part in the same position every cycle.