YAG laser is:
Near IR (1,064nm) laser beam obtained through lamp-pumped YAG (Yttrium Aluminium Garnet) crystal. It is possible to focus on a micro area, and thus very high energy density is available.
System configuration of YAG laser:
- YAG laser welder is composed of the oscillator, lamp power supply, control unit, cooling unit, optical fiber and laser output unit.
- Oscilattor: Stimulated and amplified light is irradiated as laser beam.
- Lamp power supply: Laser medium (YAG rod) is pumped.
- Control unit: Light on time, voltage and current are controlled.
- Cooling unit: Heat generated by extra lamp energy is dissipated.
- Optical fiber: Laser beam is transmitted. There are two kinds of optical fiber: Step Index (SI) and Grated Index (GI). Suitable core diameter is chosen according to the application.
- Laser output unit: Laser beam transmitted through an optical fiber is focused on a work piece. The nugget size is varied by the lens system. Multi-spot output unit and output unit with CCD camea are used according to application requirements.
Advantages of processing by YAG laser
- Deformation and HAZ are minimized thanks to very small spot size, high energy density and short welding time
- Deformation and damage are minimized thanks to non-contact processing without mechanical pressure
- Non-contact processing makes the maintenance work easy.
- There is no need to consider electrical conductivity and conductive routing.
- Welding can be performed in the atmosphere, in an assist gas atmosphere or in vacuo.
- According to applications, the location of work piece and the laser irradiation point can be moved, and multi-spot simultaneous welding and time-sharing welding are utilized. Such flexibility makes automatization easier, and facilitates downsizing and cost reduction.