Optimization of Heat Accumulation during Femtosecond Laser Drilling Borehole Matrices by Using a Simplex Algorithm

Area of Science:

• Materials Science
• Laser Physics
• Manufacturing Engineering

Background:

• Femtosecond laser drilling is a key technology for precision manufacturing.
• Heat accumulation during high-repetition-rate laser processing can degrade material quality and reduce efficiency.
• Optimizing drilling strategies is crucial for managing thermal effects in thin metal sheet processing.

Purpose of the Study:

• To optimize the spatial drilling sequence for percussion drilling of thin metal sheets using a high-power femtosecond laser.
• To minimize heat accumulation and reduce overall processing time.
• To investigate the impact of multi-spot drilling approaches on thermal behavior.

Main Methods:

• Employed a simplex algorithm for optimizing the spatial drilling sequence.
• Utilized a simplified thermal simulation (COMSOL) validated with infrared thermography.
• Investigated drilling strategies including spatial sequence and multi-spot approaches via a spatial light modulator.

Main Results:

• An optimized drilling strategy using a Moore neighborhood approach significantly reduced thermal buildup.
• The optimized strategy also led to the shortest overall process times compared to other tested sequences.
• Multi-spot approaches were explored as part of the optimization strategy.

Conclusions:

• A drilling strategy based on limited consecutive holes within a Moore neighborhood is effective for minimizing heat accumulation in femtosecond laser percussion drilling.
• This optimized strategy enhances efficiency by reducing both temperature and processing duration.
• The findings provide a pathway for improved laser-based manufacturing of thin metal components.