An upper press platen supports an upper mold member slidable vertically within a surrounding upper trim frame. A lower press platen supports a lower trim frame surrounding a lower mold member slidable vertically within the lower trim frame. The lower mold member defines a cavity connected to a vacuum source, and one or two heated sheets of material are positioned between the trim frames and mold members which are then closed to clamp peripheral portions of the sheets between the trim frames. The lower heated sheet is vacuum formed into the cavity and the sheets are fused together with heat and pressure to form a part which is then cooled. The mold members shift downwardly as a unit within the trim frames to shear the peripheral portions of the sheets from the part. The trimmed part and peripheral portions are removed after the trim frames and mold members open.