Process for drilling holes in a metallic workpiece having a thermal barrier coating

摘要

A method is provided for drilling a hole through a metallic workpiece having a thermal barrier coating with a ceramic top coat by laser drilling a counterbore to a depth which extends through the ceramic top coat but not substantially into the metallic workpiece and then laser drilling the hole through the workpiece aligned with the counterbore, the counterbore having a diameter larger than the hole.