3D printers are getting cheaper and therefore also interesting for the private user. We explain how a 3D printer works and what different printing methods there are.
Basic operation of 3D printers
Currently, there are three different 3D printing techniques. They differ in the starting material used and the modeling technique. The basic principle, however, is always the same:
As a template for 3D printing, no text file is the same as with ordinary printers, but a 3D template, which can be designed with a CAD software.
The most popular file types are STL (Standard Triangulation Language), VRML (Virtual Reality Modeling3D animations: Architecture with Unity and Cinema 4D Language) and X3D (Extensible 3D).
These templates are used to “feed” the 3D printer. The model is then built up from fusible materials, powder or also from a certain liquid.
All three popular 3D printer types have thin layers that are individually cured.
3D printers: How does stereolithography work?
Stereolithography (SLA) was already developed in the 1980s and is thus the oldest 3D printing technique.
The starting material is a liquid epoxy resin, which is located in a basin. In the basin is a lifting platform, which can be moved up and down. This is the 3D model. At the beginning of the pressure, the lifting platform is just below the surface of the synthetic resin – about 0.05 to 0.25 mm. A laser placed above the basin hardens the first layer of the model. Now the lifting platform moves down a bit. Depending on the type of printer and filigree, the layers are 0.05 to 0.25 mm thick. The epoxy resin coats over the first, already cured layer. Now the next layer of the object is cured and fits seamlessly to the first, underlying layer. Thus, the 3D model is built up layer by layer from bottom to top. The advantage of the SLA method is the smooth surface of the model. However, the liquid does not carry overhanging parts as long as they are not completely cured. Therefore support constructions may have to be used.