Abstract: A method for the regulation of the process conditions in a moulding tool which is intended for the production of products of natural or synthetic polymers. The moulding tool is made up of one or more moulding parts made of sintered metal with communicating pores obtained by pressing at a high pressure and sintering at a high temperature of a powdered material. The moulding part or parts have a moulding cavity, such that the pores are open toward the moulding cavity. The outer envelop surface of the moulding tool is tightened against leakage. The method includes filling the communicating pores with a liquid with a high vaporizing temperature and regulating the pressure on the liquid in the pores by means of a suitable pressure producer connected with the communicating pores in the moulding tool.