Method and apparatus for applying an electron beam drilling backer to a metal sheet

摘要

Disclosed is a method and fixture for applying a thin layer of polymer material to a piece of wavy sheet metal, so that the layer may function as a backer during electron beam drilling. The sheet is drawn to the smooth surface of a fixture using a vacuum, and polymer is flowed across the surface using a curved leveling board, which produces a generally uniform thickness molding. The edges of the backer are molded with a bevel edge by shaped side rails, to provide a relief around the edge of the backer layer. Thus a raised up portion usually occuring at the edge rail will not interfere with the precise spacing which the backer is intended to produce between the sheet and the workpiece holder during electron beam drilling.