Abstract: An apparatus for premetered "patch" coating discrete, incremental surfaces or substrates, such as printed circuit boards, integrated circuits and the like, with a pre-configured layer of a liquid in which a controlled volume per unit area of the liquid is applied to the substrate are disclosed. The liquid is dispensed from an applicator slot that is fluidly coupled to a liquid containing chamber. The volume of the liquid in the liquid containing chamber is varied in order to (1) sharply and distinctly start the coating "patch" by producing a pulse of liquid that flows out of the applicator slot to form a connecting bead of liquid coating on the coating surface and (2) sharply and distinctly terminate the coating "patch" by removing the bead of liquid connecting the applicator slot with the coated surface. The width of the coated "patch" is determined by the length of the applicator slot.

Abstract: A method and apparatus for premetered "patch" coating discrete, incremental surfaces or substrates, such as printed circuit boards, integrated circuits and the like, with a pre-configured layer of a liquid in which a controlled volume per unit area of the liquid is applied to the substrate are disclosed. The liquid is dispensed from an applicator slot that is fluidly coupled to a liquid containing chamber. The volume of the liquid in the liquid containing chamber is varied in order to (1) sharply and distinctly start the coating "patch" by producing a pulse of liquid that flows out of the applicator slot to form a connecting bead of liquid coating on the coating surface and (2) sharply and distinctly terminate the coating "patch" by removing the bead of liquid connecting the applicator slot with the coated surface. The width of the coated "patch" is determined by the length of the applicator slot.

Abstract: A method for temporarily sealing holes in a printed circuit board laminate during processing is disclosed. A sheet of deformable material is placed on one side of the PCB and then deformed so that the material extends into each hole to form a protectively sealing plug therein. Thereafter, the other side of the PCB is coated with a suitable resist for subsequent processing. The resist can be either photo-imagable or non-photo-imagable, such as silk screening inks, lacquers and varnishes. After conventional processing of the resist coated PCB, the deformed sheet material that forms the protectively sealing plugs is removed from the PCB. In the preferred embodiment, deformation of the sheet material is accomplished by thermally deforming a thermodeformable sheet material with a pressure differential applied across the thickness of the sheet material.