System and process for controlled removal of material to produce a desired surface contour

A method for selective and controlled removal of ablatable material from a surface in order to achieve a desired surface contour, comprising:

• providing a laser source and positioning a laser beam delivery means adjacent to the surface with the delivery means including scanning means for scanning a scan area of the surface in accordance with a selected scanning pattern;
• providing, in association with the laser beam delivery means, a surface mapping system for determining the actual contour of the surface at each of a series of sequential scan locations corresponding generally with the scanning pattern for the laser beam;
• providing a computer means with computer-stored information relating to a desired final surface contour for the surface, after milling by the laser;
• scanning both the laser beam and the surface mapping system over the scan area repeatedly, and, for each scan location, flagging that location in a computer system means for either "burn" or "no burn", as an instruction to the laser beam delivery means to either fire or not fire the laser at that scan location when the laser beam next reaches that location;
• firing the laser beam in accordance with such instructions and repeating this process through successive scans of the scan area, until the desired surface profile has substantially been achieved at each scan location in the scan area;
• and wherein the ablatable material is coated over a substrate which is not to be milled, and the method further including
• premapping the substrate surface in the scan area prior to coating the substrate with the ablatable material, to determine the surface contour in the scan area,
• storing data representing the substrate surface contour in the computer means,
• applying the coating of ablatable material to a sufficient thickness to permit a milling off of excess coating to achieve the desired final surface contour, and
• applying preselected, prestored criteria relating to permissible surface slopes to the stored data to compute said stored information representing the desired final surface contour.

A method for selective and controlled removal of ablatable material from a surface in order to achieve a desired surface contour, comprising:

• providing a laser source and positioning a laser beam delivery means adjacent to the surface with the delivery means including scanning means for scanning a scan area of the surface in accordance with a selected scanning pattern;
• providing, in association with the laser beam delivery means, a surface mapping system for determining the actual contour of the surface at each of a series of sequential scan locations corresponding generally with the scanning pattern for the laser beam;
• providing a computer means with computer-stored information relating to a desired final surface contour for the surface, after milling by the laser;
• scanning both the laser beam and the surface mapping system over the scan area repeatedly, and, for each scan location, flagging that location in a computer means for either "burn" or "no burn", as an instruction to the laser beam delivery means to either fire or not fire the laser at that scan location when the laser beam next reaches that location;
• firing the laser beam in accordance with such instructions and repeating this process through successive scans of the scan area, until the desired surface profile has substantially been achieved at each scan location in the scan area;
• and wherein the ablatable material is coated over a substrate which is not to be milled, and the method further including
• premapping the substrate with said mapping system prior to flagging "burn" and "no burn" on the scan locations to determine substrate surface contour, and
• computing said stored information representing desired final surface contour by applying preselected, prestored criteria relating to permissible surface slopes to information on the substrate profile determined by said premapping, to generate said stored information representing desired final surface contour.

Apparatus for selective and controlled removal of ablatable material from a surface coated on a substrate in order to achieve a desired surface profile, comprising:

• (a) means for premapping a scan area of the substrate and generating a first electronic signal representative of the three dimensional topography of the substrate,
• (b) means for electronically generating a second, reference electronic signal representing a desired final surface profile topography, in accordance with preselected criteria relating to permissible final surface slope and in accordance with the substrate topography as represented by the first electronic signal,
• (c) means for electronically storing the second reference signal,
• (d) means for scanning the surface of the ablatable material and for generating and storing a third electronic signal representative of the three dimensional topography of the coated ablatable material surface at each of a series of scan locations within the scan area,
• (e) means for electronically comparing the third electronic signal with the second, reference electronic signal for each scan location within the scan area,
• (f) means for impinging a high intensity beam of radiant energy, for a given period of time, on each scan location when the comparison of the third and second signals has indicated that the surface height of the coating is above the desired finished surface for that location as represented by the second, reference electronic signal, and
• (g) means for repeatedly scanning the scan area and, following the comparison of step e) for a scan location, for either impinging the high intensity beam or not impinging the beam at that scan location, based on the comparison, until the surface of each scan location substantially meets the height of the desired final surface topography for that location as represented by the electronic signal.