SLA (Stereolithography) technology is one of the first 3D printing technologies. It was patented in 1986.
It is usually referred to as SLA, Resin 3D Printing or Photopolymer 3D printing
Advantages of the SLA technology:
Fast – Subsequent layers are built up rapidly, especially in the case of DLP printers, where a whole layer is projected in a single step.
Wide range of materials to choose from.
Capable of producing elaborate details.
Layer thickness can be as thin as 0.025 millimeters.
Exceptionally smooth surface quality, where individual layers are barely noticable.
Disadvantages of the SLA technology:
Traces of support structure are visible on the prints before surfce treatment.
Most resin start to fragment if exposed to direct sunlight for an extended period of time.
SLA technology has a very wide range of possible application.
The advantages of this technology are most apparent when printing models of the smallest scales, where intricate detailwork is important. It is commonly used to print concept models, functional prototypes, scale-models, jigs or fixtures, moulds, master prototypes, dentistry models and other medical purpose models.
The desired model is first sliced into layers with a special software. Layer thickness can be specified between 0.025 and 0.1 millimeters. The sliced layers are coded into a file format that the printer can work with. Since different materials require different conditions to solidify, the desired material must be specified in the slicing software. After the choosen liquid resin is filled into the printer, the printing process can start. The machine projects the first layer onto the liquid photopolymer, which solidifies at the designated places.
The printing table is then raised by an amount bvetween 0.025 and 0.03 millimeters depending on the desired layer thickness. The process is repeated untill all the layers are complete. The print is then bathed in isopropyl alcohol to remove any residual photopolymer liquid. After the cleaning process, the print is post-processed in a UV light chamber in order to achieve sufficient firmness.