Enhancement of laser material drilling using high-impulse multi-laser melt ejection

Area of Science:

• Materials Science and Engineering
• Laser-Based Manufacturing
• Additive and Subtractive Processes

Background:

• Current laser drilling and cutting technologies face limitations in throughput and efficiency.
• Existing methods often struggle with achieving high aspect ratios and minimizing energy consumption.

Purpose of the Study:

• To develop and characterize a novel dual-laser approach for improved laser drilling.
• To investigate the parametric dependencies of this new method on various materials and laser parameters.
• To achieve significant increases in material removal rates and energy efficiency.

Main Methods:

• Utilized a gated continuous wave (CW) laser to generate a shallow melt pool.
• Employed a UV picosecond (ps)-pulsed laser for impulsive melt expulsion.
• Conducted a broad parametric study on common metals (Al, stainless steel) and carbon fiber composites, varying fluence, power, spot size, pulse length, sample thickness, and material properties.
• Incorporated multi-laser material removal rate measurements, high-speed imaging of ejecta, and multi-physics hydrodynamic simulations.

Main Results:

• Demonstrated one to two orders of magnitude increase in average removal rate and efficiency compared to single-laser methods.
• Achieved high aspect ratio holes (greater than 10:1) in samples up to 3 mm thick.
• Exceeded published energy efficiency benchmarks for drilling these materials.
• Observed similar enhancements in carbon fiber composites.

Conclusions:

• The dual-laser approach significantly enhances laser drilling performance for metals and composites.
• High-impulse multi-laser interactions, driven by surface wave instabilities and melt cavitation/ejection, are key to the observed enhancements.
• This method offers a more efficient and faster alternative for laser material processing applications.