What is Stereolithography


Stereolithography is a 3D Printing process which uses a computer-controlled moving laser beam, pre-programmed using CAM/CAD software. 

Stereolithography (SL) is an industrial 3D printing process used to create concept models, cosmetic - rapid prototypes, and complex parts with intricate geometries in as fast as 1 day. Stereolithography parts can be produced in a wide selection of materials, extremely high feature resolutions, and quality surface finishes are possible with SL. We also offer a number of secondary services such as painting, post machining and measurement and inspection, to further enhance the finish of your 3D-printed project design. 

Stereolithography design guidelines will help you understand capabilities and limitations.


How Does Stereolithography Work? 

The SL machine begins the 3D printing process by drawing the layers of the support structures, followed by the part itself, with an ultraviolet laser aimed onto the surface of a liquid thermoset resin. After a layer is imaged on the resin surface, the build platform shifts down and a recoating bar moves across the platform to apply the next layer of resin. The process is repeated layer by layer until the build is complete.

Newly built parts are taken out of machine and into a lab where solvents are used to remove any additional resins. When the parts are completely clean, the support structures are manually removed. From there, parts undergo a UV-curing cycle to fully solidify the outer surface of the part. The final step in the SL process is the application of any custom or customer-specified finishing. Parts built in SL should be used with minimal UV and humidity exposure so they don’t degrade.

Why Choose Stereolithography for your 3D Printing Project?

SL is an excellent choice for rapid prototyping and project designs that require the production of very accurate and finely detailed parts. It’s ideal for producing show-and-tell parts to enable validation of concept ideas and ergonomic testing. 

Stereolithography material data sheets can be found in our Material Comparison Guide

3DP icon logo
  • 1 to 50+ parts
  • Shipped in 1 to 7 working days
Common Applications
  • cosmetic prototypes
  • form and fit testing
  • high accuracy and surface quality


Watch: Multi Jet Fusion: What is This Used For?

For fast, quality results, Multi Jet Fusion (MJF) is unparalleled as a 3D printing process. It’s able to produce functional nylon prototypes and end-use production parts in a single day, featuring quality surface finishes and fine feature resolution. It also offers more consistent mechanical properties than similar processes like selective laser sintering.

Using an inkjet array to repeatedly apply fusing agents across a bed of nylon powder, followed by fusion into a solid layer via heating elements, MJF is able to offer complex and detailed features. Protolabs offers a commercial-grade unfilled Nylon 12 material to create durable parts. Multi Jet Fusion offers a fast and advanced way to create parts on demand. Discover more with this short video.



Watch: Differences in Major Material Types

Creating parts using 3D printing is easier than ever before, and prototyping and making design changes is fast, affordable and intuitive. The process offers a range of material types, from resin to plastic parts that are coated in metal, combining strength with lightness and flexibility.

Our ability to use Direct Metal Laser Sintering allows us to offer high-strength and temperature-resistant metallic parts quickly and cheaply, with the precision and quality you’ve come to expect from Protolabs.

Discover more about the materials we offer with this short video.

Design Guidelines: Stereolithography   

Micro resolution 3D Printing

Now for the first time if you need micro resolution parts with details as fine as 0.07mm you can prototype your designs using Stereolithography 3D printing. With our new proprietary MicroFine™ Grey and MicroFine™ Green materials and our optimised and unique equipment this is now readily available, often in just a day
MicroFine™ Grey and MicroFine™ Green

Benefits of Stereolithography


  • Competitively priced
  • Excellent surface finish
  • Easily duplicates complex geometries
  • One of the best surface finishes for an additive process


What is Stereolithography Used for?

Stereolithography is good for producing accurate prototypes and models.

Stereolithography is well used for creating accurate 3D models of anatomical regions of a patient, used to aid in diagnosis and for pre-planning and implant design and manufacture. It is also good for use in concept models and scale models.

Stereolithography is used for prototyping in order to assess design and for part validation. This is due to accuracy and its ability to produce irregular shapes.

To see an example of a part worked on by Protolabs that used our Stereolithography service, please click here.

What are the material options for Stereolithography?

Unlike older generations of SL, today’s machines offer a range of thermoplastic-like materials to choose from, with several variants to mimic polypropylene, ABS, and glass-filled polycarbonate available. Protolabs offers many variations of these materials:

View the Stereolithography Materials selector

  • Polypropylene: A flexible, durable resin that mimics a stiff polypropylene. It can withstand harsh mechanical treatment and is great for fine details—sharp corners, thin walls, small holes, etc.
  • Polypropylene/ABS blend: Strong, white plastic similar to a CNC machined polypropylene/ABS blend. It works well for snap fits, assemblies, and demanding applications.
  • ABS: Variations of ABS mimics include a clear, low-viscosity resin that can be finished clear; an opaque black plastic that blocks nearly all visible light, even in thin sections; a clear, colourless, water-resistant plastic good for lenses and flow-visualisation models; and a micro-resolution resin that enables production of parts with extremely fine features and tight tolerances.
  • Polycarbonate: A ceramic-filled PC material that provides strength, stiffness, and temperature resistance, but can be brittle.


For a more detailed look at 3D printing and Stereolithography, read our white paper on choosing the right 3D printing materials.

Please refer to our materials comparison guide for further detail to support your material selection. Additionally, applications engineers at Protolabs can help guide you during material and manufacturing process selection if help is needed.

For technical support, call Protolabs on +44 (0)1952 683047 or email: [email protected] to discuss the options available for your design.


a metal 3D printing technician removes support structures from a DMLS part

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