Laser welding of copper and aluminium: from the right settings to a controlled process
Achieving a satisfactory weld on a few parts is a first step. Being able to reproduce that result when the material, geometry or production conditions change is another matter entirely.
This difference is particularly important when laser welding materials such as copper or aluminium. Widely used in e-mobility, power electronics, energy and industrial equipment, these metals demand precise control of the interaction between the laser, the material and the intended function of the joint.
The industrial challenge is therefore not just to find the right parameters, but to understand the process well enough to be able to adapt, control and reproduce it.
Why a welding “recipe” is not enough
Laser power, welding speed, beam diameter, focal position… The result of a weld depends on a combination of many parameters.
But their influence varies depending on the material being processed.
Copper, in particular, exhibits high reflectivity at certain wavelengths and high thermal conductivity. Aluminium also has high thermal conductivity, compounded by the metallurgical characteristics specific to its various alloys.
The energy delivered by the laser is therefore neither absorbed nor dissipated in the same way from one material to another.
This is why settings developed for stainless steel cannot simply be transferred to copper or aluminium. And even between two alloys of the same family, a change in composition, thickness or geometry may require the process to be reviewed.
The question is then no longer simply: “Which parameters should be used?”, but rather: “Which phenomena do these parameters make it possible to control?”
Starting from the intended function of the joint
Even before defining the laser parameters, it is essential to know what the joint must guarantee.
In the case of a copper busbar, for example, the visual appearance of the weld seam alone is not enough to judge the quality of the joint. The joint must meet electrical, mechanical and thermal requirements in particular.
For an aluminium component, the priorities may be different: mechanical strength, leak-tightness, limiting distortion or controlling the thermal impact.
Process development must therefore take several factors into account: the material and its alloy, the thicknesses, the joint geometry, the function of the part, the loads to which it will be subjected and the associated inspection criteria.
A successful weld is not simply a good-looking seam: it is a joint capable of fulfilling, over the long term, the function for which it was designed.
From a one-off result to a robust process
Once an initial parameter window has been identified, one key question remains: what happens when real production conditions vary?
Raw materials vary. Geometries and joint gaps can change. Part positioning is never perfectly identical. Production conditions themselves can introduce new variations.
An industrial process must be able to accommodate these realities.
This means determining which parameters really influence the result, identifying acceptable operating margins and putting relevant inspections in place.
This approach makes it possible to move gradually from settings that work to a process window that is understood and controlled.
Process control also depends on skills
This robustness does not rely on technology alone.
When a defect appears or a material changes, teams must be able to understand what is happening and determine the right course of action: should the power be adjusted? The speed? The focusing? The preparation or geometry of the joint? Is the problem really due to the laser parameters?
This analytical capability becomes decisive when the process has to be transferred to production.
Knowledge cannot then remain concentrated in the hands of a few specialists. It must be structured, documented and shared so that teams can develop, optimise and maintain the process over time.
Understanding for better industrialisation
Ultimately, laser welding of copper and aluminium illustrates a challenge that extends far beyond these two materials.
Industrialising a laser process is not about looking for a universal recipe. It is about understanding the interactions between material, energy, geometry and joint function, and then turning that understanding into parameters, inspection criteria and reproducible methods.
It is with this in mind that IREPA LASER also supports the upskilling of industrial teams through its laser welding training courses, from process fundamentals to the specific issues associated with copper and aluminium alloys.
Because between “getting a weld right” and “mastering a welding process”, the difference often lies in the ability to understand why the result works - and to know how to reproduce it.
Would you like to deepen your laser welding skills?
IREPA LASER offers several training courses dedicated to laser welding, from process fundamentals to more specific issues relating to materials and industrial applications.
> Discover our laser welding training courses and find the one that suits your needs.
