Abstract: A polymerization apparatus includes a first chamber and a second chamber and a flexible, radioparent diaphragm separating the first chamber from the second chamber. A radiation source emitting polymerization-inducing radiation into the first chamber is provided. The second chamber is adapted for receiving a model and a foil, positioned between the diaphragm and the model, to be subjected to the radiation of the radiation source. A device for generating a pressure differential between the first and the second chamber for deflecting the diaphragm toward the model to thereby deform the foil at the model is provided. An adjusting device for adjusting the distance between the model and the diaphragm is provided.