Combined laser system for metal welding

A combined laser system (100) for metal welding, comprising:

• a first light source (110) configured to generate and emit a first laser beam having a relatively short wavelength for preheating before welding and heat treatment after welding;
• a second light source (120) configured to generate and emit a second laser beam having a relatively long wavelength for welding;
• a first steering mirror (130) configured to reflect the second laser beam and steer an incident angle thereof;
• an optical combiner (140) configured to combine optical paths of the first laser beam and the second laser beam and form a combined beam;
• a second steering mirror (160) configured to reflect and steer the combined beam in a Y-axis direction;
• a third steering mirror (170) configured to reflect and steer the combined beam in an X-axis direction;
• and
• a scan lens (170) configured to scan the combined beam reflected from the third steering mirror (170) on a working plane,
• wherein positional deviation between an irradiation region and a designed working region, which occurs when the combined beam passes through the scan lens (180) due to a refractive index difference according to different wavelengths of the first laser beam and the second laser beam, is corrected in the following order:
• a correction of X-axis and Y-axis positions of the first laser beam, a correction of X-axis and Y-axis positions of the second laser beam, and a correction of X-axis and Y-axis positions of the combined beam.