LASER BEAM MACHINE AND FOCUSING METHOD THEREFOR

摘要

A laser beam machine capable of carrying out a focusing operation, a preparatory operation for laser beam machining, automatically and accurately, and a focusing method for a laser beam machine. A laser beam machine is provided with a means for determining the times of production start and termination of blue flame on the basis of the condition of generation of plasma and data on the position of a machining lens which are stored in time sequence, an information processor for determining the position of the machining lens at the above-mentioned two points in time, and a focus position calculating element for calculating a suitable focus position on the basis of the two positions of the machining lens determined in the information processor.