Determination of the focus position in the introduction of laser cutting

Determination of the focus position in the introduction of laser cutting. Laser cutting machine is introduced in industrial production and a simple method to determine the focus position is as follows: ( 1) Blue spark method: remove the nozzle, blowing air, will play on stainless steel plate, the pulse laser makes the cutting head from the top down movement, until the blue sparks as the focus. So we can calculate the focal point, after cutting process according to different plate thickness different corresponding focusing. Flying light path of the cutting machine, as a result of beam divergence Angle, cutting the proximal and distal time path length is different, focusing the beam size before have certain difference. The diameter of the incident beam is larger, the smaller the diameter of the focal spot. In order to reduce the focus beam size change before the change of the focal spot size, domestic and foreign manufacturers of laser cutting system provides some special device for users to choose. ( 2) Inclined plate method, the application and a vertical axis Angle of inclined put plastic board makes its pull, level and looking for a laser beam as the focus of the small. ( 3) Printing method: this will make the cutting head from the top down movement, laser print on the plastic sheet, print small diameter as the focus. ( 4) Parallel light pipe. This is a very common method, that is, at the output of the CO2 laser beam expander of parallel light pipe processing, expanded beam after the beam diameter, divergence Angle smaller, so in cutting work within the scope of the proximal and distal focused beam size close to agreement before. Increase in the cutting head under a separate mobile lens axis, it and control the nozzle to the material surface distance ( 站) The Z axis is part two independent of each other. When the machine table to move or optical axis direction, the beam from the proximal to distal F axis move at the same time, also make the light beam focusing spot diameter after consistent throughout the processing area. ( 5) Can be controlled focusing mirror ( General focus for metal reflection system) The water pressure. If by narrowing the focus beam before and make the focal spot diameter was larger, the automatic control water pressure change focus curvature make focal spot diameter smaller.