In 3D printing, the component is built up layer by layer from one or more liquid or solid materials according to specified dimensions and shapes, just like a CNC machine based on CAD/CAM data. Physical or chemical hardening or melting processes take place during construction.

Typical materials for 3D printing are plastics, synthetic resins, ceramics and specially prepared metals (for example in powder form). In the meantime, carbon and graphite materials have also been developed for 3D printing parts made of carbon. Although these are often forming processes, a specific product does not require special tools that have stored the respective geometry of the workpiece (for example, casting molds).

3D printers are used in industry, model making and research for the production of models, samples, prototypes, tools, end products and for private use. In addition, there are applications in the home and entertainment sector, the construction industry as well as in art and medicine.

These processes are used in the parallel production of very small components in larger quantities, for unique pieces in jewellery or in medical and dental technology, as well as in small series production or individual production of parts with a high geometric complexity, also with additional functional integration.

In contrast to master molds, forming or subtractive manufacturing processes (machining, cutting), 3D printing increases its cost-effectiveness with increasing complexity of the component geometry and decreasing quantities required. "3D printing does not make sense in every case, but above all where geometrically complex components have to be realized in small quantities," says Dr. Klaudius Henke, research associate at the Technical University of Munich.

Another strength of 3D printing is the ability to build complex shapes that are difficult or impossible to produce with other machines. For example, the Sagrada Família construction workshop uses 3D printers to create models for Antonio Gaudí's very sophisticated architectural forms. Its vaults consist of large rotating hyperboloids with hyperbolic paraboloids inserted in between.

At the same time, additive manufacturing processes enable new product properties or differentiated use of materials and can thus lead to savings or substitution of scarce resources such as rare earths. This allows products to be manufactured more efficiently or more sustainably.

Other fundamental advantages over competing manufacturing processes lead to an increasing spread of the technology, also in the series production of parts. Compared to the injection molding process, 3D printing has the advantage that there is no need for the time-consuming production of molds and mold changes. Compared to all material removal processes such as cutting, turning and drilling, 3D printing has the advantage that the additional processing step after primary forming is omitted. In most cases, the process is more energy-efficient, especially if the material is only built up once in the required size and mass. Other advantages are that different components can be manufactured and produced on one machine.