Sheet metal processing method using laser beams and direct diode laser processing device for carrying it out

A sheet metal processing method, comprising:

• oscillating laser beams of multiple wavelengths from a DDL module;
• transmitting the oscillated laser beams of multiple wavelengths;
• and
• processing by cutting a sheet metal with a processing head that condenses the transmitted laser beams of multiple wavelengths and irradiates them onto the sheet metal that is an aluminum plate with a thickness greater than or equal to 1 mm and less than or equal to 5 mm, while using an assist gas that is nitrogen with a pressure of greater than or equal to 0.8 (MPa);
• wherein a surface roughness (Ra) of a cut surface of the cut aluminum plate is less than or equal to 2.5 μm.

A direct diode laser processing device, comprising:

• a DDL module for oscillating laser beams of multiple wavelengths;
• a transmission fiber for transmitting the laser beams of multiple wavelengths oscillated by said DDL module;
• and
• a laser processing machine for processing by cutting a sheet metal with a processing head that condenses the laser beams of multiple wavelengths transmitted by said transmission fiber and irradiates them onto the sheet metal, wherein when a mild steel plate with a thickness greater than or equal to 1 mm and less than or equal to 5 mm is cut while using an assist gas that is oxygen with a pressure of 0.05 (MPa) to 0.2 (MPa), a surface roughness (Ra) of a cut surface of the cut mild steel plate is less than or equal to 0.4 μm, and when an aluminum plate with a thickness greater than or equal to 1 mm and less than or equal to 5 mm is cut while using an assist gas that is nitrogen with a pressure of greater than or equal to 0.8 (MPa), a surface roughness (Ra) of a cut surface of the cut aluminum plate is less than or equal to 2.5 μm.