Stereolithography Apparatus also knows on as SL (Stereolithography),is a 3D printing process that converts UV sensitive photopolymer liquid resin into solid parts, layer by layer, by selectively binding the liquid together using a UV laser beam in a process known as photopolymerization. Patented in 1986 by its inventor, SLA is famous for being the first 3D printing technology.
The build platform is positioned just above the tank of liquid resin with one layer of the liquid resin on the platform. The UV laser then selective cures or binds the liquid together in a predetermined path. Once the layer is complete the build platform lowers itself into the liquid tank another layer. This process continues till the part is complete.
The liquid resin are composed of chemicals that are activated by the light of a UV laser and bind together to become solid. This process is irreversible and there is no way to convert SLA parts back into 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.
SLA technology is capable of making highly accurate and precise parts with speed while also creating the smoothest surface finish parts of all 3D printing processes. SLA parts are generally brittle and degrade overtime if exposed to sunlight making them unsuitable for functional prototypes.
SLA 3D Printing is ideal for:
- forward - Parts with high dimensional accuracy with intricate details
- forward - Prototypes for limited functional testing
- forward - Patterns for investment casting and vacuum casting
- forward - Low volume production of complex geometries
- forward - Parts for testing form, fit and assembly
Technical Specifications for SLA
forward Standard Lead time: Minimum 4 working days depending on part size, number of components and finishing requirements lead time may increase.
forward Standard Accuracy: ± 0.025mm - 0.05mm
forward Layer thickness (resolution): 0.016 mm
forward Minimum Wall thickness: 1mm
forward Max dimensions: 298mm x 183mm x 203 mm. Large parts can be created by assembling individual parts by interlocking designs or glueing them together.
forward Surface finishing and Post Processing: Unfinished parts typically have visible building layers on the surface but post-production finishes can achieve different effects, from high glosses to coarse textures. Stereolithography parts can be sandblasted, smoothed, colored/impregnated, painted, varnished, covered and coated