The Stereolithography Process
In 1986 Chuck Hall, founder of 3D Systems developed the first Stereolithography (SLA) machine, a system by which physical models are built layer by layer in a vat of UV curable liquid resin using 3D CAD data. The Stereolithography Process creates a solid resin model, accurate to within 0.1mm of the original CAD data.
The Stereolithography Process:
1. The 3D CAD data is converted into a STL file using proprietary software that slices the model into a series of fine layers. Support structures are also added to the file at this stage. Once the STL file is complete it is then sent to print on the Stereolithography machine.
2. Using a UV laser beam the first cross section of the STL file is drawn onto a vat of UV curable resin (on exposure to the laser the liquid resin cures).
3. Once the first layer is complete the platform is lowered by 0.05-0.15 mm (depending on the build mode selected – standard SLA/ high resolution SLA) with a fresh layer of resin covering the build surface. The next layer is traced out, curing and bonding the resin to the layer below.
4. The process repeats layer by layer until the model is fully “grown” in the resin.
5. Once completed the machine platform rises allowing excess resin to drain away before the model is removed from the platform. SLA technicians then wash the SLA model and remove any supporting structures. Any customer specified finishing and painting is then carried out.
“We had been using CNC to produce highly accurate models. But Rapid Prototyping produced parts 4 times faster at half the cost”