Abstract: A method and device for producing multilayer printed circuit boards, under the application of heat and pressure to a stack of printed circuit boards and interposed layers of thermosetting plastic, the multilayer stack being heated in a first press to a curing temperature above the flux point of the bonding layers, then precooled under continued pressure to a transfer temperature below the flux point and transferred to a second press, where it is aftercooled under pressure to ambient temperature. The press installation of the invention includes two independently operating multi-stage presses in a common press frame. The plates of the press stages are horizontally aligned in the open position of the two presses.

Abstract: A device for controlling a heated panel press in the switchover from a contact pressure mode to a curing pressure mode, in connection with the assembly of multilayer stacks of printed circuit boards with interposed thermosetting resinous bonding layers, the device consisting essentially of a displacement transducer measuring the decrease in the stack height in terms of displacement pulses and a pulse counter and count comparator producing a switchover signal at a predetermined threshold count which reflects attainment of the flux point in the bonding layer resin. After an adjustable delay, the switchover signal is transmitted to the control unit of the press.