Developments in Nd :YAG laser welding

Laser welding in keyhole (KH) mode using solid-state laser emitting in near infrared at nearly 1 micron wavelength is discussed in this chapter. The main physical processes involved in laser welding are presented and the reasons for using this laser wavelength are shown. Section 3.2 describes the KH geometry and related physical mechanisms controlling its stability. The role of the main operating parameters is also presented. Section 3.3 shows examples of the evolution of keyhole and weld pool behaviour for various welding speeds illustrating the mechanisms discussed in Section 3.2. Finally in the conclusion, expected diagnostics improvements necessary for supporting adapted numerical simulations of this laser welding process are discussed