SLA：Technically, stereolithography was developed decades ago and uses highly responsive plastic resins. Under normal conditions, this resin is an easy to handle liquid. However, when exposed to the correct type of radiation (usually from directional laser light), the resin permanently hardens into a new form.
SLA printers simply apply this process to 3D printing. They are also printed layer by layer, but instead of extruding the material, the cans filled with resin liquid are cured layer by layer according to a pre-set path.
The process begins with a resin fluid and an ultraviolet laser that can be carefully aligned to the resin underlayer. The SLA printer uses a very complex 3D file to illustrate the location of the aiming laser. Printers typically contain a cradle for creating 3D objects. When the object is built layer by layer, the base moves through the liquid trough and slowly lifts it from the depth.
However, these layers have a thickness of less than one hundred microns and are formed very quickly. These layers are not bonded together by the irregular melting of the FDM filaments, but are bonded together at a chemical level, essentially giving the object a very high surface finish.
What are the benefits?
- Detailed objects: If the layer is indivisible and less than 100 microns, you can create objects with incredible detail.
- Strength: A variety of different photosensitive resins allow the creator to choose the quality of the object to be printed. In general, these creations will be much more powerful than FDM objects. This provides more practical use for SLA objects.
- Prototype options: SLAs are better suited for creating prototypes for testing purposes, or even mass-producing certain components.
- Inadequacies of SLA：Moving parts is still a problem – no matter how good the slicing and layering techniques are, common 3D printing problems are still relevant.
SLA printers are also more expensive than FDM due to the price of the resin and the complexity of the printer. Resins are also proprietary, which means you have less flexibility in choosing what you want to print.