40 3D printing of components for aircraft, launchers, satellites, space stations, helicopters, military equipment; 3D printing of components; 3D printing of components of metal; customized manufacture of three-dimensional objects of metal, ceramics, plastic, silicone, wax or combinations of the aforesaid materials through treatment of materials, for others; 3D printing; electron beam melting; electron beam- powder bed melting, laser sintering, laser melting, laser-powder bed melting, in particular of metals and plastics; mask sintering, namely, customized additive manufacturing using the selective mask sintering method; treatment of materials, namely, customized manufacture of models, patterns, prototypes, tools and end products using additive manufacturing processes; treatment of materials for prototypes, patterns, models, moulds and small series parts and mass production parts by laser beam; 3D printing using stereolithography 3D modelling; rental of rapid-prototyping machines and 3D printers; rental of 3D printers; rental of rapid-prototyping machines and 3D printers