Through - hole plating of printed circuits - with holes drilled before surfaces are plated

摘要

The circuits are formed on opposite sides of the substrate (made of glass fibre reinforced epoxy resin or polyamide) after the holes have been drilled. They are then degreased, chemically cleaned, impregnated and activated and then the plating is applied chemically. The plating is Cu, Ni or a Su/Pb alloy. The process provides much improved coverage of the surfaces of the holes, and improved adhesion of the plating applied.