Procedure for soldering the constituent layers of a multilayer printed circuit and the machine used for same

Procedure for soldering the constituent layers of a multilayer printed circuit, applicable to multilayer printed circuits made up of a mix of layers containing the circuit image (2, 3, 4 and 5) and isolating layers (6, 7 and 8), the layers with the circuit image (2, 3, 4, 5) having perimetral strips (9) where multiple reserve areas (11) are located in equal number and arrangement for each layer that includes the following steps:

• i) place a heater circuit (13) composed of a flat winding with at least one turn in short-circuit (14) in the reserve area (11) of each layer containing the circuit image (2, 3, 4 and 5);
• ii) arrange the layers containing the circuit image (2, 3, 4, 5) so that they are superimposed and separated from each other by an isolating layer (6, 7 and 8) in order to create the book of layers of the multilayer printed circuit, in which can be distinguished a top layer containing the circuit image (2) and a bottom layer containing the circuit image (5);
• iii) secure the position of the layers (2, 3, 4, 5, 6, 7, 8) of the multilayer printed circuit (1), relative to each other, in such a way that the corresponding reserve areas (11) of the layers containing the circuit image (2, 3, 4, 5,) occupy the same relative position, thereby creating groups (12) of superimposed reserve areas (11) and, consequently, groups of superimposed heater circuits (13);
• iv) in each group (12) of reserve areas (11), place one induction electrode (18) over the reserve area (11) of the top layer containing the circuit image (2), and a induction electrode (19) over the opposite side of the reserve area (11) of the bottom layer containing the circuit image (5);
• and
• v) solder each group (12) of reserve areas (11) by application through the two induction electrodes (18, 19) of a magnetic field of variable induction, that generates through induction in each of the turns in short-circuit (14) of each heater circuit (13) of each reserve area (11) of each layer containing the circuit image (2, 3, 4, , and 5) a current intensity whose circulation through the turns in short-circuit produces the heat necessary to solder the layers (2, 3, 4, 5, 6, 7, 8) of the multilayer printed circuit (1).