Erik Tolf

Abstract

High power lasers such as CO2, Nd:YAG, diode, disc and fiber lasers are suitable for material processing such as welding and cutting. Recently, the fiber laser has been receiving attention due to its advantages with high power, high beam quality and high efficiency.

Fiber lasers as well as thin disc lasers are distinguished by their strong focusability enabling deep penetration welding and cutting at high welding speeds. Keyhole welding with focus diameters down to 50 μm are possible using high laser power. However, to utilise small focus diameters for deep penetration welding the divergence angle has to be sufficiently small to achieve a large depth of focus.

Laser welding in keyhole mode requires a high power laser source (>1 kW) with a spot size of 0.8 mm or smaller.

Laser cutting requires a high power laser source (>0.5 kW) with a spot size of 0.6 mm or smaller.

Laser brazing can be performed with all commercial high power (>1 kW) laser sources with a spot size of 3 mm or smaller.