A heat-affected zone of less than 0.5 mm, welding speeds up to 10 m/min, and dimensional tolerances of ±0.05 mm—these are parameters that no conventional method can simultaneously achieve. However, laser welding isn't the answer to every job. It requires precisely cut parts, clean surfaces, and a reasonable production volume. In this article, we compare laser welding with MAG, MIG, and TIG welding on a technical level—with specific data, without marketing simplification—so that the reader can consciously assess whether and when this technology makes sense for them.

What is laser welding and how does it differ from conventional methods?

Laser welding involves concentrating the laser beam into a focal point with a diameter of 0.1–0.6 mm, which allows for achieving a power density of 10⁶–10⁷ W/cm². The metal melts and solidifies rapidly, creating a weld with a high depth-to-width ratio (effect keyhole).
Conventional methods work differently:

• MAG/MIG – Heat comes from the electric arc between the electrode wire and the material. Wide fusion zone, significant thermal deformation, often requiring grinding of the riser.
• TIG – more precise than MAG/MIG, but slow and labor-intensive; requires a skilled operator.
• Laser – automatically guided beam, without or with minimal filler material, with a welding speed 3–10× higher than TIG.

The key difference lies in method of supplying energy. The laser concentrates it in a micro-area and in a fraction of a second, while a traditional electric arc heats a much larger area over a longer period of time.

Laser metal welding – precision, repeatability and a narrow heat-affected zone

The technical heart of the laser advantage lies in the parameter HAZ (Heat Affected Zone – heat affected zone). In MAG welding this zone is a few millimeters; in laser welding it is usually 0.1–0.5 mm. In practice, this means minimal deformation of the part, preservation of the mechanical properties of the base material near the weld, and no need for post-process straightening.

Penetration depth at the same power is several times greater than with TIG – 3–6 kW lasers weld materials up to 6–8 mm thick in a single pass. Dimensional tolerances of the finished joint are routinely within the range of ±0.05–0.1 mm.

In serial and automotive production it is also important repeatability. Robotic laser heads operate with consistent parameters throughout the entire shift, eliminating human variability. This translates directly into compliance with ISO 3834 standards and acceptance by TÜV and IATF 16949 auditors.

➤ You can find more about automation in welding in the article about evolution of welding robots.

Laser welding of steel – applications in the production of supporting structures and packaging

Carbon steel (S235, S355) and stainless steel (304, 316L) are materials where laser welding performs exceptionally well. The high beam absorption in ferritic and austenitic steels allows for welds 0.3–2 mm wide with full penetration and a near-mirror aesthetics. without grinding. In stainless steel, a narrow HAZ eliminates the risk of grain boundary sensitization and susceptibility to intergranular corrosion.

Strumet uses laser welding in production, among others. metal containers for the automotive industry – elements where surface aesthetics, dimensionality and resistance to dynamic loads must be guaranteed simultaneously.

Laser welding of aluminum – challenges and advantages over TIG/MIG

Aluminum poses more challenges: its thermal conductivity of ~205 W/m·K (compared to ~50 W/m·K for steel) quickly removes heat from the weld zone. This is further compounded by the Al₂O₃ oxide layer (melting point ~2050°C), a tendency to weld porosity, and the risk of hot cracking.

Laser in pulsed mode or with power modulation, precisely controls the thermal balance. The result is welds with porosity below 1% – a requirement of aviation standards (EN 4179) – and joint strengths of 85–95% of the parent material for 5xxx and 6xxx alloys. This result is difficult to achieve using the MIG method.

Laser welding – advantages and disadvantages in the context of industrial production

The greatest operational advantage of laser welding is elimination or significant reduction of finishing. Laser welds on stainless steel and aluminum often require no grinding or polishing, which translates directly into shorter cycle times and lower unit costs in mass production. Minimal thermal deformation in turn, means that the details retain their dimensions after welding without additional straightening. Finally, process repeatability allows you to maintain constant parameters throughout the entire production shift, which is difficult to achieve with manual TIG.

The main barrier is entry cost (although this problem is solved by e.g. industrial cooperation). There is also a requirement for the preparation of details - the gap between the joined edges should not exceed 0.05-0.1 mm of the material thickness, which requires precise laser cutting or punching before welding. over 10–12 mm laser loses its advantage over MAG without the use of hybrid techniques.

When is laser welding truly profitable? Technology selection criteria

Laser is the best option when:

1. Production volume is high or repetitive – depreciation for series of several thousand pieces per year.
2. Material: stainless steel, carbon steel, aluminum or titanium alloys – aesthetics and minimal HAZ are critical.
3. The thickness of the material is 0.5–6 mm – the laser is faster and more precise than TIG; below 0.5 mm it almost completely replaces it.
4. Strict dimensional control is required – tolerance ±0.1 mm and below, zero acceptance for deformation.
5. Cycle time has economic significance – an assembly line with a 60-second cycle cannot wait for a multi-pass TIG.
6. The welding geometry is complex – the laser head on the robot freely follows curved paths.

Traditional methods remain the optimal choice when:

1. The production is individual with high variability of geometry and the budget does not justify the investment.
2. The material is thicker than 10-12 mm without low HAZ requirements.
3. Tolerances and gaps between edges exceed 0.3 mm.

It is worth basing the decision on analysis total life cycle costs (TCO). The laser pays for itself by reducing the costs of finishing, scrap, and labor time – items often underestimated at the pricing stage.

FAQ – frequently asked questions about laser welding

Is laser welding suitable for small-scale production or only mass production?

Laser processing is best economically justified for batches of several hundred to tens of thousands of parts per year. In small batches, it is used when quality requirements—precision, low HAZ, aesthetics—preclude other methods; the unit cost is higher but technologically justified.

What materials can be joined using the laser method – is it possible to weld different metals?

Laser welding allows for the joining of various metals: steel with stainless steel, copper with brass, or selected aluminum alloys with titanium – with the appropriate selection of parameters and filler material. This is more challenging than TIG welding, but feasible and used in applications such as electronics and medicine.

How does laser welding compare to MAG/TIG in terms of weld strength?

A properly executed laser weld achieves 85–100% of base metal strength – comparable to TIG and often better than MAG, where a wide HAZ weakens the weld zone. The key lies in the quality of joint preparation and control of process parameters.

Does laser metal welding require special surface preparation of the parts?

Yes – surfaces must be free of oil, rust, and coatings, and the gap between edges should not exceed 0.05–0.1 mm of material thickness. In practice, this means precision laser cutting or punching of the details immediately prior to welding.

Does your project require precise, aesthetically pleasing welds while maintaining tight dimensional tolerances? Strumet has the own machinery park and experience in laser welding of steel and aluminum for demanding industries. Contact us, describe the order and we will select the process parameters and assess feasibility before issuing a quote.