Arc discharge quickly jumped from 19th-century physics labs and fairground demonstrations into industrial workshops—no engineer could ignore such a source of energy. The arc claimed a permanent territory in the realm of ultra-high temperatures. Interestingly, the patent for industrial welding using an electrode-based electric arc predates classical gas welding methods. The industrial boom, from skyscrapers to ship hulls, demanded temperatures and combustion conditions that gas simply couldn’t handle, especially with tungsten and titanium. Aluminum and magnesium, meanwhile, were practically impossible to weld with gas at the time.
The laser lagged behind electricity by literally half a century, and its industrial adoption was slower and more expensive: high-quality rubies were rare, and synthetic ones were pricier than natural. The laser quickly began closing the technological gap, but arc welding didn’t stand still either. Every invention has room to grow. Competition between TIG and laser welding started showing its effects about 20 years ago, but the final split has only materialized recently.
Let’s "balance the scales" from the laser’s perspective, and then contrast it with TIG’s capabilities:
Humble Laser
Laser welding is highly adaptable, as the focus allows for precise control of energy density. Pulsed modes expand this range even further. Here are the advantages from an engineering perspective:
1. Extremely Simple Automation
Laser welding can often be performed without filler material—no flux, electrodes, or solder is needed. Effective welding requires only control of the beam itself. This reduces process complexity by at least half, as the filler is unpredictable in consumption, temperature, and melt behavior. Welding two 1 mm steel sheets via TIG is already challenging, while two 0.5 mm magnesium sheets can instantly clump due to uneven heat distribution. Areas unreachable by inert gas may even burn or oxidize into powder.
Interrupting filler supply at the wrong moment can ruin the weld entirely, requiring manual repair. Manual TIG, however, does produce good results, limited only by the operator’s experience.
2. Heat Efficiency
Lasers have high efficiency; modern compact hand-held devices lose only about 30% of energy as heat. This applies even to relatively simple devices, making laser welding energy-efficient.
3. Precision
Laser focus allows spot heating. In pulsed mode, it mimics classical spot welding but with much higher energy in a smaller area. Heat affects only 1.5–2 beam radii around the weld, which neither arc nor gas welding can match in precision.
4. Precision vs. Thermal Conductivity
The laser acts quickly and aggressively but precisely. Heat doesn’t spread significantly, resulting in straight and aesthetically clean welds. It also avoids "thermal shock," making it compatible with many materials—including magnesium and low-melting plastics.
5. Magnesium + Polyethylene?
Instant heating avoids uneven melting. Laser welding enables combinations previously impossible, like stainless steel with thermoplastics, or mixing high-carbon steel, cast iron, copper, aluminum, magnesium alloys, and many plastics.
6. Multi-beam Integration
Laser systems can integrate multiple beams for heating and welding simultaneously, something impractical with TIG. Pulsed and continuous lasers can work together efficiently, even handling complex materials. Using inert gas with lasers provides the benefits of both traditional and modern methods.
Mighty TIG
Tungsten Inert Gas (TIG) welding is an older but highly practical method. An electric arc forms between the tungsten electrode and the workpiece at ~3300°C, melting even refractory oxides. Inert gases like argon or helium shield the weld. Helium can dissolve slightly in molten metals, sometimes making the weld brittle, but TIG remains popular and versatile.
1. Material Flexibility
TIG can weld almost all types of steel, nickel, aluminum, magnesium, copper, chromium, and even delicate metals like gold foil. Despite plasma’s extreme temperatures, skilled operators can manage heat to avoid deformation.
2. Filler Material Advantage
Using filler wire allows TIG to fill macro-cracks and gaps while balancing heat for gradual cooling. Lasers typically avoid this effect, while TIG uses it deliberately to ensure strength and ductility.
3. Cost Factor
The TIG setup is relatively inexpensive, and retraining welders is minimal. Filler materials may cost extra (especially helium for fine work), but TIG welds are generally cheaper than laser welds—though this is becoming debatable.
4. Automation Limitations
TIG’s automation and integration are limited. Controlling one arc with one filler rod is manageable; two arcs are far more challenging. Minor improvements over the years—flux-assisted filler, AC/DC variations, arc-start techniques—helped but didn’t fully modernize the process.
Different Strokes for Different Folks
TIG is excellent for small workshops requiring manual flexibility, compact equipment, and quick adaptation to various metals. Laser welding excels in precision, speed, clean welds, minimal thermal impact, automation, and compatibility with sensitive materials.
