Abstract: 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.

Abstract: 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.

Abstract: A panel for electric heating, with an outer hermetic aluminum shell, an inner shell with a rectangular base and a cover, inside which is an ohmic resistance in the shape of a planar serpentine, formed of a series of U-bends and having two pseudo-circular endings that extend to the inside of a hermetic contact module integrated with the outer shell, wherein the serpentine is made of a rigid bar having a rectangular section, wherein the base of the inner shell incorporates a thick layer of oxide that favors infrared irradiation, and wherein an internal thermal insulator hinders the flow of heat towards the cover.

Abstract: Panel for electric heating has an outer hermetic aluminum shell, an inner shell with a rectangular base and a cover, inside which is an ohmic resistance in the shape of a planar serpentine, formed of a series of U-bends and having two pseudo-circular endings that extend to the inside of a hermetic contact module integrated with the outer shell. The serpentine is made of a rigid bar of stainless AISI 304 steel having a rectangular section, constant width and thickness, and a width-to-thickness ratio of less than 3. Two sheets of mica contact the inner shell and the cover, one on each face of the serpentine, insulate it from the outer shell and minimize the free internal spaces. The base of the inner shell incorporates a thick layer of oxide, black in colour, formed by hard anodizing, favouring infrared irradiation. An internal thermal insulator hinders the flow of heat towards the cover.