Chemical or electroplating appts. - for depositing metal in holes in printed circuit boards via several solns. fed successively through hole

摘要

A nozzle is aligned on each side of the board so the nozzles are coaxial with a hole to be metallised; and a control appts. is connected to each nozzle. The two control units are used for the selective feeding of liqs. via pumps from storage tanks, so each liq. flows through the hole in the board and is then returned to its tank, i.e. each liq. flows in a closed circuit. One of the nozzles contains an anode, which can be connected to a d.c. supply when electroplating is required. Modern boards may contain up to 25 holes/sq.cm; and not all the holes are completely metallised when they are pressed in laminated boards. The invention is used to correct any faulty boards, i.e. where some holes are not completely metallised.