Abstract: A method and apparatus for adjusting the reference system of a pre-programmable laser device relative to the position of an inscription field of a part to be processed such as a silicon wafer characterized by a laser beam from a laser operating in a continuous wave mode being programmed to travel in various search motions with each motion traversing and passing over an edge of the part. The light which is unblocked by the part is received by a photoelectric element to trigger a position signal for each time the light passes across the edge of the wafer. The precise position of the wafer or part relative to the reference system is calculated from the position signals with the assistance of a computer and subsequently the coordinates of the reference system are corrected to match the precise position of the part.