HOT PRESS

PURPOSE:To apply an optimum pressure distribution on objects to be adhered and to form an adhered material having less dimensional change and no remaining foam by providing means for preventing deformation of the object and control means for said means on the heat insulating plate side of a bolster. CONSTITUTION:Objects 15 to be adhered of multi-layered printed wiring boards, etc. are inserted between a lower hot plate 6 and an intermediate hot plate 8 as well as between the plate 8 and an upper hot plate 10 of a hot press. Forming heat energy is applied on the plates 6, 8, 10 and an oil pressure is supplied to a main ram cylinder 2 to press the plates 6, 8, 10. A control oil pressure is supplied to a counter cylinder 9 and the control oil pressure to an auxiliary ram cylinder 26 in this stage, then a deformation of a smooth projecting shape is generated on the upper heat insulating plate 11 side of a cushion plate 29 by the thrust of a ram 27, by which the recessed deformation arising on the object 15 side is prevented. The resin of a fluid medium flows toward the outside circumferential direction while the adhering sheets of the objects 15 flows and at the same time the internal foam which is the factor for defective insulation is removed to the outside.