Hybrid BLUE + NIR Laser Welding: enabling the next generation of stator welding

Reducing the axial length of radial flux motors is becoming an increasingly challenging requirement as manufacturers strive for more compact, efficient, and lightweight electric motor designs.

To address this trend, IMA AUTOMATION is exploring advanced laser welding technologies to minimize heat diffusion and enable more compact stator designs. The benefits are clear: optimized copper usage, reduced motor length, and lower overall weight. Current motor innovations mainly follow two paths: X-pin technology and mini-pin designs. Both solutions require shorter stripped wire sections, increasing the risk of damaging copper insulation during welding.

Traditional Near-Infrared (NIR) laser welding faces limitations on copper due to its low absorption coefficient, requiring high energy to initiate the keyhole process. Our tests showed that BLUE laser wavelengths provide significantly higher copper absorption, reducing the energy needed for keyhole generation.

This led us to develop a hybrid laser solution, combining the strengths of both wavelengths:

• BLUE laser ensures efficient keyhole formation with lower energy input, reducing porosity and spatter.
• NIR (Traditional Near-Infrared) laser accelerates the welding process once the keyhole is established.

A key innovation is the development of a galvo scanner capable of managing both wavelengths simultaneously, enabling precise control of the welding process and maximizing the benefits of the hybrid approach. Developed in collaboration with EL.EN., this solution reduced the energy required at the welding joint to approximately 2.65 kW, compared to the 6 kW typically required by NIR-only systems, while also delivering around 30% cycle time savings. Lower power consumption and shorter cycle times reduce the Heat Affected Zone (HAZ), enabling the reliable processing of shorter stripped wires and supporting the next generation of compact electric motor designs.

As the electric motor industry continues to evolve toward higher power density and smaller footprints, hybrid BLUE + NIR laser technology represents a promising step forward in stator welding, combining efficiency, quality, and productivity in a single solution.