Laser Beam Keyhole Effect
The laser keyhole effect creates a vapor- and plasma-filled capillary in the weld zone through extreme power density, enabling deep welds.
Physico-Chemical Mechanism of Action
A high-energy laser beam focuses on a small spot on the workpiece. The extreme heat creates a capillary filled with vapor and plasma. This allows the laser to make deep welds without excessive heat input.
Metallurgical Relevance & Welding Risks
The keyhole effect can cause high pressure and rapid cooling, altering the material's microstructure. Incorrect settings can lead to uneven distortion or lack of fusion. It's critical to control the power density and focus of the laser precisely.
Shop Practice & Operating Instructions
To use the keyhole effect effectively, follow these parameters:
• Power Density: 1000 W/cm² or higher
• Focal Diameter: 0.2 mm to 0.5 mm
• Travel Speed: 10 cm/s to 30 cm/s
• Standoff Distance (Laser-to-Workpiece): 1 mm to 3 mm
Make sure the laser is aimed directly at the workpiece and check welds regularly. Use a high gas flow rate (e.g., argon) to support the keyhole.