System and process for controlled removal of material to produce a

Abstract

A method and apparatus for controlling the milling of an ablatable material and the like from substrate is disclosed. Embodiments for controlling the milling of ablatable materials and the like by pulses of high intensity radiant energy are described. The control process is accomplished by generating an electronic signal representative of the substrate surface topology through use of a structured light or other three dimensional mapping system and feeding the signal to a system control unit. By applying pre-programmed criteria regarding the final desired surface to the generated electronic signal, an electronic reference signal indicative of the dimensional coordinates of the final desired surface may be generated. An ablatable coating is then applied to a height sufficiently above the final desired surface to permit a milling off of the excess coating to produce the desired final surface topology. In the milling process the mapping system is used as a real-time feedback control mechanism for directing a laser. By scanning the surface ahead of the laser, the mapping system generates a new electronic signal representative of the coated surface topology, and this signal is compared to the desired-topology reference signal. At each spot where the comparison indicates the coated surface is above the final desired surface, the controller will order the laser to fire upon that spot, and this is reiterated until the surface features fall within the prescribed limits.