Rapid Prototyping - Stereolithography Apparatus (SLA)

The Rapid Prototyping Stereolithography (SLA) process was developed by 3D Systems of Valencia, California, USA, founded in 1986. A vat of photosensitive resin contains a vertically moving platform. The part under construction is supported by the platform that moves downward by a layer thickness (typically about 0.1 mm / 0.004 inches) for each layer. A laser beam traces out the shape of each layer and hardens the photosensitive resin.

SLA Highlights

  • First Rapid Prototyping technique.
  • Inexpensive compared to other techniques.
  • Uses a light-sensitive liquid polymer.
  • Requires post-curing.
  • Long-term curing can lead to warping.
  • Parts are quite brittle and have a tacky surface.
  • No milling step so z accuracy suffers.
  • Support structures are typically required.
  • Simple process: No milling or masking steps.
  • Uncured material is toxic.