Stereolithography (SLA) is an additive manufacturing process that belongs to the Vat Photopolymerization family. In SLA, an object is created by selectively curing a polymer resin layer-by -layer using an ultraviolet (UV) laser beam. The materials used in SLA are photosensitive thermoset polymers that come in a liquid form.
Stereolithography was the world’s first 3D printing technology, invented in the 1980s, and is still one of the most popular technologies for professionals. SLA resin 3D printers use a laser to cure liquid resin into hardened plastic in a process called photopolymerization
Here is how the SLA fabrication process works: The liquid resin is solidified through a process called photopolymerization: during solidification, the monomer carbon chains that compose the liquid resin are activated by the light of the UV laser and become solid, creating strong unbreakable bonds between each other. The photopolymerization process is irreversible and there is no way to convert the SLA parts back to their liquid form: when heated, they will burn instead of melting. This is because the materials that are produced with SLA are made of thermoset polymers, as opposed to the thermoplastics that FDM uses.
Fused Deposition Modeling (FDM) also known as Fused Filament Fabrication (FFF), is a quick and cost-effective way of producing parts out of thermoplastics. FDM is the most widely used 3D printing technology. It is suitable for the production of functional parts, Concept prototypes, form and fitment prototypes, Batch production.
SLA is best suited for applications where high detail or high accuracy is
required. Create high fidelity prototypes/
functional parts for medical, dental, Automotive, jewelry, casting, etc. Tough
Resin(Elastomers), High-Temperature Resin, are some of the most used materials
for SLA 3d printing.
Selective Laser Sintering (SLS) uses synthetic thermoplastic polymers, such as nylons. SLS is suitable for affordable batch production, complex geometries, or for producing strong parts. Parts produced using SLS are porous, and have decent mechanical strength. PA2200 is the most widely used material for this process.
Direct Metal Laser Sintering (DMLS) and Selective Laser Melting (SLM) are both used in the production of metal parts with excellent physical and mechanical properties. Suitable for Complex geometries of metal, creating Lightweight metal parts. A variety of superalloys/metals can be 3d printed using this process.
One of the fastest 3D printing technology, Polyjet is suited for realistic prototypes, and if high accuracy, smooth surface finish are important requisites. Polyjet can print in multiple materials and colors. Polyjet is mostly used for concept prototypes, not suitable for engineering applications or functional parts.
Multi Jet Fusion (MJF) is one of the fastest processes producing quality plastic parts with detailed features. The parts printed in MJF exhibit consistent mechanical properties, low porosity and are usually light grey in color. It's suitable for small batch production as an alternative to injection molding.