Laser drilling is a well-established technique for metals and alloys, widely used across aerospace, automotive, and medical industries.

However, drilling ceramics - especially thick alumina exceeding 5 mm - presents a formidable challenge due to its high melting point, brittleness, and low absorption of standard fiber laser wavelengths.

A new study has tackled this challenge by exploring laser trepanning drilling of 6 mm thick alumina, focusing on the material removal process and how key parameters affect hole quality and thermal damage. Researchers systematically investigated pulse energy, frequency, assist gas composition, and trepanning speed to identify optimal drilling conditions.

Key findings include:
• A minimum specific energy of 80 J/mm is required to form through-holes, while crack formation begins beyond 640 J/mm.
• Oxygen was the most effective assist gas, producing minimal taper despite no reactive fusion. • Optimal drilling performance is achieved by balancing pulse energy (for stable hole geometry and minimal thermal damage), frequency (to control thermal effects), and trepanning speed (to reduce taper and thermal impact).

These insights offer a practical roadmap for precision drilling of thick alumina ceramics, a material critical for high-performance applications in extreme environments.