Abstract:
A method of fabricating a multilayer printed circuit board, comprises alternately stacking on a template (1) having at least two vertical alignment pins (2), predefined printed circuit sub-boards (3) and pre-impregnated sheets (12) precursors of dielectric layers of reinforced resin between said sub-boards, all provided with alignment holes (14, 5), binding together the components of the assembled stack, lifting the stack off the alignment pins (2), transferring it between the platens of a press and hot pressing it causing polymerization of the resin of said pre-impregnated sheets. The method consists in defining at least a pair of soldering pads (7) with hole therethrough at certain positions relative to said alignment holes (14, 5) on both faces of each of said sub-boards (3) except the lowermost sub-board on which blind pads (6) are defined on at least its upper face; indenting or perforating each pre-impregnated sheet (12) such not to overlap said pads (6, 7) and soldering each newly stacked sub-board (3) to the previously stacked underlying sub-board (3) through the respective pads (7) with a hole therethrough. The machine employs a template (1) having at least two vertical alignment pins (2); a least two electric soldering irons (16), soldering each sub-board (3) just stacked to the previously stacked underlying one through welding pads (7) having a hole therethrough and has means (18) for moving each one of said soldering irons along three orthogonal axis onto a respective one of said pads (7) with a hole therethrough to make the soldering, and off and away from the stack when the soldering have been done.
Abstract:
An automatic machine for hot laminating a dry photoresist film (3, 4) supported on a peelable-off cover sheet onto a board (1) for printed circuit, includes at least a pair of hot laminating rolls, transfer means for feeding a preheated board to the inlet side of said pair of laminating rolls (11, 12), at least a supply roll of a rolled-up continuous ribbon of said supported dry photoresist film, vacuum means holding (5, 6) a free end portion of the supported dry photoresist film ribbon, means for pressing and tacking the leading edge of said vacuum held free end portion of the ribbon at a given position on a surface of a board moving towards the inlet side of said pair of laminating rolls, cutting means (17, 18) associated to said ribbon end holding and tacking means for cutting to measure, on account of the length of the fed board, the dry photoresist film ribbon carried along by the moving board (1) onto which the leading edge of the ribbon has been tacked by said tacking means, and means (13, 14) for heating said supported dry photoresist film at a certian temperature before laminating it through said pair or rolls. Said holding, tacking and cutting means translate together with the board (1), said holding, tacking and cutting means translate together with the board (1) and then return to their start position.
Abstract:
An automatic machine for hot laminating a dry photoresist film (3, 4) supported on a peelable-off cover sheet onto a board (1) for printed circuit, includes at least a pair of hot laminating rolls, transfer means for feeding a preheated board to the inlet side of said pair of laminating rolls (11, 12), at least a supply roll of a rolled-up continuous ribbon of said supported dry photoresist film, vacuum means holding (5, 6) a free end portion of the supported dry photoresist film ribbon, means for pressing and tacking the leading edge of said vacuum held free end portion of the ribbon at a given position on a surface of a board moving towards the inlet side of said pair of laminating rolls, cutting means (17, 18) associated to said ribbon end holding and tacking means for cutting to measure, on account of the length of the fed board, the dry photoresist film ribbon carried along by the moving board (1) onto which the leading edge of the ribbon has been tacked by said tacking means, and means (13, 14) for heating said supported dry photoresist film at a certian temperature before laminating it through said pair or rolls. Said holding, tacking and cutting means translate together with the board (1), said holding, tacking and cutting means translate together with the board (1) and then return to their start position.
Abstract:
The dispersion of thermal energy through domestic hot water discharges from showers, wash basins, domestic electrical appliances, etc., is substantially reduced by recovering heat in an exchanger through which the flow of cold water derived from the mains is passed and is directed either to the delivery by means of a mixer member simultaneously with discharge or to the delivery of hot water or water which is to be heated in general. The exchanger can advantageously be incorporated in the base of a shower pan, or otherwise incorporated into domestic electrical appliances.