METHOD AND APPARATUS FOR EVALUATING LASER WELDING

An apparatus for monitoring a weld process in which energy (12) is delivered from a laser source (10) to a workpiece (18) along a process path to create a weld, includes a first sensor (26) for monitoring a first weld characteristic of the weld and providing an electrical signal indicative of the first weld characteristic. A second sensor (33) monitors a second weld characteristic and provides an electrical signal indicative of the second weld characteristic. The apparatus also includes a controller (31) that determines (116) a maximum variance of the first weld characteristic and a maximum variance of the second weld characteristic. The controller also determines (128) if the determined maximum variances occur at locations on the weld which are substantially the same. The controller (31), when the maximum variance of the first weld characteristic and the maximum variance of and the second weld characteristic occur at locations on the weld which are substantially the same weld location, compares (138, 144, 150) values functionally related to the first and second weld characteristics against associated predetermined anomaly values indicative of a weld anomaly. The controller produces an error signal when it determines that the value functionally related to the first or the second weld characteristic is indicative of a weld anomaly.