Patent ID: 8030593

Claim:
A laser welding apparatus for performing welding by irradiating a laser beam, comprising: a laser oscillator for generating a laser beam; a laser irradiating device for changing an irradiating direction of the laser beam and operable to irradiate the laser beam at a laser irradiating point located at a second distance from the laser irradiating device; a laser irradiating pointer laser diameter measuring device for calibrating the diameter of the laser beam at a laser irradiating point; a replaceable beam guiding device operable to guide the laser beam from the laser oscillator to the laser irradiating device, wherein the beam guiding device has a laser emitting end; a collimating lens disposed on the laser irradiating device between the laser emitting end and the laser irradiating point at a first distanced from the laser emitting end of the beam guiding device, the collimating lens being shaped to output an inputted laser beam as a parallel beam; a condensing lens for condensing the parallel beam prior to irradiating the laser irradiating point; a distance changing device operable to change a first distance between the laser emitting end and the beam guiding device and the collimating lens; and a control unit programmed to: determine an optimal diameter of the laser irradiating point using the laser irradiating point laser diameter measuring device, the optimal diameter corresponding to the second distance between the laser irradiating device and the laser irradiating point; store a first relationship between a plurality of laser irradiating point diameters at the laser irradiating point and corresponding post-collimation laser diameters of the parallel beam such that each of the laser irradiating point diameters corresponds to an optimal diameter with respect to the second distance from the laser irradiating device to the laser irradiating point as the second distance varies; and actuate the distance changing device to obtain an optimal laser diameter of the laser beam at the laser irradiating point based on the first stored relationship.