Polymerisation is a chemical reaction in which monomers, mostly unsaturated organic compounds, react under the influence of catalysts and with the dissolution of the multiple bond to form polymers (molecules with long chains consisting of monomers linked together). A distinction is made between homo-polymerisation, in which only one type of monomer is reacted, and co-polymerisation, in which two or more different monomers are made to react. Polyamide 6 castings are produced exclusively by such a process and can thus be manufactured in a variety of shapes and dimensions. This process also allows the addition of modifications such as oil or solid lubricants, which adapt the property of the material to the respective application.