A press station for a forming machine for forming articles from paper has a chamber consisting of two halves. The two halves of the chamber are able to be closed together and the chamber can be evacuated through a main vacuum manifold in order to bring the upper die mounted on a first platen into pressing contact with a fragile moulding positioned on a second platen in order to form the required article.

In a machine such as a press having at least one heating platen and one cooling platen, it is proposed to place between the said platens a variable heat conduction device (22a), when the operation of the machine requires a phase of heating the part without the application of pressure, followed by a phase of cooling the part under pressure. This device (22a) has two thermally conductive plates (32a, 34a), normally separated by a space under vacuum (52a) under the action of at least one deformable member (36a), which can be elastic or plastic. The application of the pressure passes the device (22a) from a thermally insulating state to a thermally conductive state.

A method and apparatus to form a long, thin laminated strip of plastic, metal and fiberglass. The uncured laminate will be laid up in a housing which has sidewalls and a base. A partition is placed over the laminate. The partition seals to sidewalls of the housing and is movable relative to the housing. The partition divides the cavity of the housing into an upper section and a lower section. The lower section is evacuated. Gas or fluid pressure is applied to the upper section. Heat is applied to the housing to cure the laminate while the pressure is maintained. Tension is applied longitudinally to the laminate during the process.

In a hot press according to the present invention, a control panel detects the fact that the viscosity of bonding resin of multilayer circuit board materials is minimized by taking thereinto at least one of the values measured by a speed sensor of a lower bolster, a measuring portion for measuring a control current of an electromagnetic proportional relief valve and a relief amount detector for detecting the relief amount of the electromagnetic proportional relief valve, and gives an instruction of an optimum air pressure addition timing. Accordingly, even if the multilayer circuit board materials and the like are varied, it is always possible to change over from a vacuum condition to an air pressure added condition at the best timing, thereby making it possible to obtain a multilayer circuit board of a uniform thickness without causing generation of void.

A fixture having a bottom plate, top plate and an expansion block interposed between the bottom plate and top plate. A workpiece is positioned between the expansion block and bottom plate. When the fixture is heated, there is a net displacement exerted by the expansion block so as to apply pressure to the workpiece. The pressure applied by the fixture to the workpiece is due solely to the thermal expansion of the fixture when it is heated.