StereoLithography Apparatus

In 1986, inventor Charles W. Hull and entrepreneur Raymond S. Freed founded 3D Systems, Inc., which in 1988 came out with the first commercial Rapid Prototyping (RP) system, the StereoLithography Apparatus (SLA). Today several SLA models are available, including the series of SLA 250/30A, SLA 250/50, SLA-250/50HR, SLA 3500, SLA 5000, SLA 7000 and Viper si2.

StereoLithography (SL), uses the concept of layer additive construction, and builds objects by curing successive thin slices or layers of specific ultraviolet (UV) light-sensitive liquid photopolymer resins, with a low-power UV laser.
The successive layers are built on top of the previous layer, thereby fabricating a 3D part. The self-adhesive characteristic of the photopolymer bonds the layers securely. However, the irradiation of the UV light does not fully cure the photopolymer and most parts have to undergo a post-curing process, which increases their mechanical properties in a direct proportion.
A cleaning solvent is also used to clean up any residual resin after the part has been built on the machine.

3D Systems, Inc., developed the STL format for use with the SLA, which produces a physical 3D model based on an STL format file. The format became an industry standard due to its simplicity of comprising only triangles represented by three vertices and a surface normal vector.
With advancing research however, this format needs updating as it can sometimes lead to incorrect geometry.

SL produces the greatest accuracy and the most acceptable finish among all the RP technologies. Continuing research is going on all around the world, and further improvements in SL, STL, and SLA are anticipated in the near future along with the growth of RP technologies.

Share and Enjoy: