How Does It Work

How Does it Work | Computer to 3-D Object: The Process | Materials Used

Size and Shape Limitations | Cost/Time Restraints | Where Can It Be Done?

Since the Stereolithography is the most common RP (rapid prototyping) technique you must first convert the CAD model of your part to STL (Stereolithography) format. The STL file contains the coordinates of the vertices and the directions of the outward normal of each triangle. The third step is to slice the STL file so the Stereolithography machine can make the part layer by layer. Once the file is sliced and sent to the SLA machine and part can be made. The part is made from liquid photosensitive polymers that solidify when exposed to ultraviolet light.

The process starts out with an empty platform with a vat of liquid epoxy or acrylate resin below it. The empty platform slowly lowers into the vat as the laser traces out and solidifies each layer according to the instructions it receives from the STL file. A sweeper re-coats the solidified layer with liquid. Then the laser can trace and solidify the next layer atop the previous. The excess areas of liquid epoxy can be disposed of after the part of made.

Figure 1: Schematic diagram of stereolithography.

Once the part is constructed it must be rinsed clean of excess liquid and detached of any supports. It should then be placed in an ultraviolet oven for completion.