SLA is one of the most widely used industrial 3D Printing technologies in use today. SLA offers highly accurate and detailed polymer parts in over 28 different resins. SLA was invented by Charles Hull and introduced to the market in 1988 by 3D systems.
An SLA machine uses a highly focused UV laser to trace out successive cross-sections of a 3D CAD file in a vat of liquid photopolymer. As the laser traces the layer, the polymer solidifies and the excess areas stay as a liquid. When a layer is finished, a leveling blade is moved across the surface to smooth it before solidifying the next layer. The platform is lowered/elevated by a distance equal to the layer thickness (typically 0.004-0.002 in), and a subsequent layer is formed on top of the previously completed layers. This process of solidifying and smoothing is repeated until the build is complete.
Once the part is completed, it is raised above the build vat and drained. Excess polymer is rinsed away from the part surfaces. A final cure is done by placing the part in a UV oven. After the final cure, supports are removed and surfaces are polished, sanded or otherwise finished.
Benefits of SLA 3D Printing
- The most accurate and detailed models
- Very good surface finish
- Many resins available including high temperature and clear materials
- Fast print speed
- Very little wasted support material
Applications for SLA 3D printing
- Appearance models
- End use parts
- Clear parts
- Medical models
- Casting patterns