Abstract: A double opening press comprises an intermediate movable plate, a lower fixed plate and an upper movable plate. Heating platens are connected to the upper movable and lower fixed plates and to upper and lower surfaces of the intermediate plate. The intermediate plate is rigid in structure and has dielectric layers between itself and the heating platens connected thereto so that the heating platens can be heated using high frequency energy. The intermediate plate and structures connected thereto are grounded and need not be made of electrically insulating material.