| 摘要 |
In manufacturing multilayer plastic laminates for printed circuits, a press with two surfaces exerts pressure under vacuum on a stack of laminates, the packs, alternated with separator plates made of anodized aluminum. The packs include prepreg layers. The metalizations present on the two sides of each pack are portions of a copper strip repeatedly folded 180° around each pack and each separator plate. A strong current circulates in the copper strip which heats the strip with resistive behavior: the heat causes the close fixing of the various layers. An auxiliary heater is applied to each surface of the press by element of an interposed insulating plate. This includes an aluminum plate with equidistant longitudinal holes containing the same number of armored candle-like resistors, connected in parallel. A main power supply provides direct current to the copper strip, two secondary power supplies provide alternating current to the two auxiliary heaters. |
| 主权项 |
1. A method for manufacturing multilayer plastic laminates for printed circuits, comprising:
a) constructing a stack of single multilayer plastic laminates, below termed packs, alternated with separator plates that are thermally conductive and electrically insulated, each pack comprising dielectric layers metalized on at least one face alternated with pre-preg adhesive layers, the two outermost layers of each pack being constituted by respective portions of at least one metallic tape, repeatedly folded 180° in opposite directions in order to form loops of a serpentine that systematically crosses the stack over the entire height thereof; b) applying, under vacuum, pressure of controlled value on said stack by means of a two-plate press and simultaneously generating heat inside the stack, the heat being developed by the electric current made to circulate in the serpentine metal tape, with resistive behavior, by a main electric generator whose power supplied to the metal tape is controlled in a manner so as to increase according a pre-established gradualness the temperature measured inside the stack for a time sufficient for hardening the adhesive layers and achieving therefore the mutual fixing of the various layers as well as of the metal tape portions to the layers mating thereto; c) returning to the initial pressure and temperature conditions; d) cutting the metal tape flush with the opposite flanks of the stack from where the metal tape exits outward, and disassembling the single packs metalized in such manner, wherein during step b) an additional calorie intake is supplied to the two ends of the stack by means of two auxiliary resistive heaters constrained to the two plates of the press and thermally insulated therefrom, said auxiliary heaters being power-supplied by respective secondary electric generators controlled in a manner so as to increase the temperature of the auxiliary heaters according to the aforesaid pre-established gradualness, being the power dissipated by the auxiliary heaters enough for obtaining in respective top and bottom packs of the stack approximately the same temperature as measured inside the stack. |
