METHOD FOR LASER MICROMACHINING

A method of laser micro-machining, by means of a laser, a work piece ( 31 ) of the type described comprising the steps of: locating the workpiece on a carrier forming a part of a transport system whereby the carrier can be displaced along a path (P) parallel to an X-axis of the workpiece, a Y-axis lying transverse the path, and a Z-axis lying transverse the path; focusing an image generated by means of an output beam from the laser at a working datum position (A) defined relative to the path which path is established by means of the transport system to traverse the first datum position; a plane defined by the X- and Y-Axis lying substantially perpendicular to the output beam; and displacing the workpiece along the path by way of the transport system so as to enable the work-piece to be subject to micro-machining by way of the laser characterized by the steps of: maintaining distance between the datum position and a current first surface position of the work-piece in the vicinity of the datum position; and varying the working datum position to accord with local variations in thickness of the workpiece so that the working datum position is maintained at a fixed distance relative to a surface of the workpiece apparatus therefor.