Method to locate the focus position of CO2 laser cutting machine！

Use a piece of flat and smooth white cardboard, lay it flat on the workbench, set the laser cutting head above it, and the height of the focusing lens from the cardboard is 10mm smaller than the focal length of the focusing lens. For example, if the focal length of the focusing lens is 127mm, set the focusing lens approximately 117mm away from the cardboard. The CNC system sets the cutting head to move every 10mm along the x-axis or y-axis, and the z-axis rises 1mm with each movement. The interval of 20 consecutive movements can be set. CO2 Laser Cutting Machine each time it moves into place, use the laser to emit a 200W pulse laser to punch a hole in the cardboard. Move 20 times to drill a total of 20 holes, and increase the z-axis height by 20mm. Observing these 20 holes, we can find that the diameter of the holes gradually changes from large to small, and then from small to large. Find the direction where the hole diameter is the smallest, which is the focus direction, and record this. Measuring the distance between the cardboard and the lens in this position is the actual laser beam focus position.