There are Five ways to determine focus position in laser cutting processing:

1) Blue spark method: Remove the nozzle, blow air, and hit the stainless steel plate with a pulse laser, moving the cutting head from top to bottom until the big blue sparks become the focus. In this way, the focus can be calculated, and in the later cutting process, the corresponding focus can be adopted according to different plate thicknesses.

2) Inclined plate method: Use a plastic plate placed at an angle to the vertical axis to pull it horizontally, and find the small part of the laser beam used in laser cutting as the focus.

3) Printing method: Move the cutting head from top to bottom, and print the laser beam on the plastic plate, with the small diameter of the print being the focus.

4) Collimator: This is a common method, which is to add a collimator to the output end of the CO2 laser to expand the beam. After beam expansion, the diameter of the beam becomes larger and the divergence angle becomes smaller so that within the cutting working range, the size of the beam before focusing at the near and far ends is close to the same.

5) Add an independent lower axis of the moving lens to the cutting head, which is two independent parts from the Z axis that control the distance from the nozzle to the material surface. When the laser cutting machine tool table moves or the optical axis moves, the beam also moves from the proximal end to the far end F-axis, so that the spot diameter after focusing the beam remains consistent throughout the entire processing area.