Quasi-Continuous Wave Pulsed Laser Welding of Copper Lap Joints Using Spatial Beam Oscillation

Area of Science:

• Materials Science
• Manufacturing Engineering
• Laser Processing

Background:

• Laser beam welding of copper presents challenges due to high thermal conductivity and reflectivity.
• Near-infrared laser welding of copper requires advanced techniques to ensure weld quality.

Purpose of the Study:

• To investigate the effects of spatial beam oscillation on laser welding of copper (Cu) in a lap joint configuration.
• To demonstrate control over laser weld quality and dimensions using oscillating parameters.
• To identify optimal oscillation parameters for improved Cu-Cu joining.

Main Methods:

• Utilized quasi-continuous wave (QCW) pulsed laser beam welding for 0.4 mm to 1 mm Cu sheets.
• Employed spatial beam oscillation with varying amplitudes (0.2-0.8 mm) and frequencies (100-400 Hz).
• Compared oscillated laser beam welding with non-oscillated welding to evaluate weld characteristics.

Main Results:

• Laser beam oscillation significantly reduced spatters and porosities, improving surface quality compared to non-oscillated welds.
• Weld width was primarily controlled by oscillating amplitude, while penetration was influenced by both amplitude and frequency.
• Increased oscillating amplitude led to wider welds and decreased penetration; increased frequency reduced penetration with minimal effect on width.

Conclusions:

• Spatial beam oscillation is an effective method for enhancing laser weld quality and controlling dimensions in copper joining.
• Optimal parameters, such as 0.8 mm amplitude and 200 Hz frequency, yielded a high width-to-depth ratio and a maximum tensile force of 1944 N.
• This technique offers a viable solution for overcoming challenges in laser welding of copper.