Stereolithography (SLA) is the oldest 3D printing method. It was invented in 1983 by Chuck Hell and patented in 1986. It is the oldest additive method and is still being used today.
In a liquid bath filled with a base monomer (liquid plastic), the workpiece is created with a laser by means of exposure to UV light. The plastic consists of photopolymers such as synthetic resin or epoxy resin.
A wiper applies a layer of the liquid plastic onto the preceding layer. A laser controlled by movable mirrors travels over the newly created layer, thus curing it. In this way, the workpiece/model is created layer by layer. Like all other 3D printing methods, the model is created layer by layer with material being added gradually. Hence, the name “additive method”.
After the layer has been hardened by means of the UV laser, the fabrication platform is lowered a few millimetres and a new layer of liquid plastic is added. In this way, the component is made step by step. Stereolithography is an extremely precise method that enables the fabrication of very filigree objects with an especially smooth surface.
Without supporting structures, the component would float away in the liquid plastic bath. These supporting structures are created in the form of small columns during the component fabrication process. They consist of the same material as the component itself. After completion, they are removed mechanically.