a method and apparatus is disclosed for forming lines of weakness in an automotive trim piece so as to enable formation of an airbag deployment opening in the trim piece . a cutting beam , such as a laser is directed at the trim piece surface to be scored and a sensor emits a sensing beam , and a beam combining device receives both the sensor beam and the laser beam and causes downstream beam segments to be collinear with each other as they impinge the trim piece surface . the scoring is thereby able to be carried out in a single pass , and is precise , repeatable and independent of cutting depth , angle of cutting , scoring patterns , material inconsistency , material color , and surface grain variability .