SLA is an additive manufacturing process that was introduced and invented in 1986. In fact, SLA was the technology used to manufacture the first 3D printed parts. This technology uses a vat photopolymerization process and the materials used in the SLA are mainly thermoset polymers in a liquid state. This 3D printing method provides parts with a lot of detail.
SLA works on the principle of light curing, using a high power laser that hardens the polymer according to the CAD design. The print platform is positioned one layer high away from the surface of the liquid in the liquid polymer resin tank. The UV laser creates the next layer by selectively curing and solidifying the photopolymer resin. The cross-sectional area is continuously scanned to ensure that each layer is completely solidified before moving on to the next layer.
When a layer is finished, the platform is moved to a safe distance and the sweeping blade coats the surface with resin. This process is repeated several times until the entire part is produced.
The finished part is removed from the printer and washed in isopropyl alcohol to remove excess resin. If the part is made with supports, these can be removed after printing is complete. After that, additional post-processing takes place by passing the part through ultraviolet light to obtain more rigidity and higher mechanical and thermal properties.