Pressure-punch device for film welding

In a pressure stamp device for the sealing of films with a slidable stamp element with a stamping surface for applying pressure to a first foil to bond it to a supported second foil, a substantially homogeneous internal temperature distribution is reached by contributing the stamping element with multiple layers so that it includes basically three layers with a heated central layer of a first material with a thermal conductivity and two peripheral layers of a second material flanking it, the surface being formed by one of the peripheral layers to constitute the stamping surface.