Similar to a traditional frame and used in multiformat moulds , the exchangeable frame is designed for a certain format. The own frame is the one that is tied to the supports, by means of a pierced that remains in other exchangeable frames of the same mould. The liners remain fixed inside the windows anchored by means of allen screws. The frame is endowed with a heating system tied in the low part and can include also a system of cleanliness. It can be made of reversible form.