Stereolithography, from liquid to 3D model at the speed of light

Stereolithography (SLA)

Today we are going to discuss another method of 3D printing named stereolithography (SLA). Really it is just another big word for a pretty simple concept. SLA uses a liquid plastic that is placed in a container, within which is a platform very similar to a platform in a FDM printer. The liquid which is called a photopolymer, is simply a liquid which when exposed to light (usually UV) polymerizes into long strands forming a solid. This is similar to the photopolymer that dentists use to fill cavities, and what that funny blue light is for.


The photopolymer used for 3D printing is not as safe as ones used in dentistry. Therefore, when handling 3D printer photopolymer that is in liquid form, gloves should be worn at all times.

At the beginning of a SLA print, the submerged platform is raised to the surface of the liquid. A UV laser is then used to draw the first essentially 2D layer of the model. The platform moves down and the second layer is solidified by the laser. This continues until the model is completed.


SLA still requires support material for overhangs just like FDM. However, since the resolution of SLA is much greater than FDM, the removal of the support material is easier and leaves almost no artifacts.

Below is a video made by 3D Systems that explains the process in a very Lord of the Rings tone.

Until recently this type of 3D printing was very costly, about $250,000 for one printer!

However, a company named Formlabs has created a SLA printer that costs only $3,299. The platform actually works a little differently in this printer. It is not fully submerged in the liquid and works by raising the model out of the container.


Here’s a interview of of the creators of the printer at Maker Faire 2012.

Examples: These models were produced on the Form 1 printer.



Posted on June 10, 2013, in 3D Printing and tagged , , , , , , , , . Bookmark the permalink. Leave a comment.

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