Laser welding can be divided into the following processes.

Thermal welding and keyhole (deep penetration) welding
Thermal welding is a laser welding method that uses a low-power laser beam. This ensures that the penetration depth does not exceed 1-2 mm. It has the ability to handle a relatively large power range, can adjust the heat transfer welding to an ideal power level, and the shallow weld can weld heat-sensitive materials under optimal conditions.
This welding type is used for thin plate welding applications such as butt welding and lap joints. It can also be used for welding hermetic seals and other seals. Thermal welding is also suitable for volatile alloys that are not suitable for small hole (deep penetration) welding, such as magnesium and zinc.

Keyhole welding (deep penetration welding) uses high-power laser beams for high-speed welding. The fine and deep penetration can achieve uniform welding of the internal structure. Since the heat affected area is very small, the deformation of the substrate due to welding heat is minimized.
This method is suitable for applications that require deep penetration, and for welding a variety of stacked base materials (butt joints, corners, T-shaped, wound joints, flange connections, etc.).