SLA Printing

How Does Stereolithography (SLA) 3D Printing Work?

01 3D Model Preparation

A CAD model is first prepared that describes the geometry and features of the part in 3D. To prepare it for printing, it must be imported into “slicer” software, which converts it into layers that an SLA printer can interpret. This process also generates support structures, which are needed to prevent unsupported features like overhangs from damage. The part should be oriented to minimize the need for supports.

Engineer, Constructor, Designer in Glasses Working on a Personal Computer. He is Creating, Designing a New 3D Model of Mechanical Component in CAD Program. Freelance Work

02 The Part Build

The build table in an SLA printer is positioned just below the surface of a vat of liquid resin. A UV laser or light source traces the shape of the first layer onto the resin, causing it to cure and solidify. After a layer is complete, the build platform moves down by the thickness of one layer. A recoater blade moves across it to apply the next layer of resin. The process repeats as the part is built, layer by layer.

03 Post Processing

When the build is complete, the part is removed from the vat and any support structures are removed. It is then washed with a liquid solvent to remove any uncured resin from its surface. The part is then cured with UV light to ensure that it is fully solidified and has reached its maximum strength. Finishing options include sanding, painting and clear coating. Clear SLA resins can be polished to an optically clear finish.

Is SLA Right For Your Application?

Advantages

High-Quality Surface Finish

The excellent surface finish and dimensional accuracy of SLA prototype parts make them ideal for testing for fit and finish.
Clear Parts

Fathom’s SLA printing service can print parts using a clear resin which can be sanded to an optically clear finish that is almost glass-like in appearance.
Small Layer Size

SLA can print in layers as small as 0.002 inches. That enables it to produce very fine details and cosmetic-quality surfaces.
Print Complex Shapes

Thanks to its fine resolution (hundreds of microns), stereolithography 3D printing can be used to print thin walls, sharp corners, small holes and complex shapes.
Tolerances

SLA offers some of the tightest dimensional tolerances of any additive manufacturing technology.
Larger Prototypes

SLA enables the production of larger, lightweight prototype parts, using internal lattice structures for support.
Easy to Post-Process

Parts produced by Fathom’s SLA printing service are easy to finish by sanding, painting and/or clear coating.

Disadvantages

Sensitivity to UV Light

SLA parts are produced using photopolymers, which means they may become brittle over time when exposed to sunlight.
Not the Strongest Additive Technique

SLA parts are not always as robust as those produced using other thermoset or thermoplastic additive technologies. For that reason, they are not always recommended for functional components. Ask your industrial 3D printing service if SLA is the right additive process for your application.
Support Marks

SLA doesn’t offer the option of dissolvable supports. When supports are removed from parts, they may leave visible marks, which require post-processing to remove.

Applications of SLA

Stereolithography produces parts with accurate, detailed features and a high-quality surface finish that is perfect for creating visual prototypes. SLA prototypes are popular within industries that rely heavily on new product innovation, including but not limited to:

Medical technology
Education
Dentistry
Engineering and product design
Manufacturing
Prototyping

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What Can SLA be Paired With?

SLA can be paired with a variety of other 3D printing technologies to offer a comprehensive solution for visual or form-fit prototypes.

Traditional Technologies That Can Benefit from SLA

If you’re currently leveraging machining or other traditional methods to produce prototype parts, SLA may be an inexpensive and flexible alternative. It’s one of the least expensive 3D printing technologies. It can be used to produce detailed, accurate parts with an excellent surface finish that is perfect for testing fit and finish.

Unlike machined parts, which require fixturing and set-up, parts produced by Fathom’s SLA printing service can be produced quickly at low cost, making them an ideal solution for your rapid prototyping needs.