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SLA 3D Printing Service

Stereolithography Parts On Demand

3d Printed SLA propeller blue tinted

What Is Stereolithography?

Stereolithography (SLA) is a vat polymerization 3D printing process and is the original 3D printing process that is still widely used today for its accuracy and speed. SLA is often used for prototypes, large concept models, form and fit models, investment casting patterns, and master patterns.


Dimensional Accuracy and Smooth Finishes

Stereolithography can create high dimensional accuracy parts with intricate designs and smooth surfaces. It also allows us to print watertight components in clear materials making it easy to test fluid flow found in product designs. 


Virtually Limitless Part Size

At Stratasys Direct we can build extremely light, large-scale parts in record time utilizing our sparse fill, which is a hollow build method. Sparse fill is ideal for nonstructural appearance models. These parts build faster, weigh less and cost less than solid SLA models. They also have a better as-built surface than 10-20 pound foam. 

Stereolithography 3D printing showing laser mid-build

How Sterolithography (SLA) Works:

Stereolithography (Monikers: Vat photopolymerization, photocuring, SLA, SL) relies on a precise UV laser to cure liquid resin layer by layer. Its build platform sits just below the top of the resin bath. The build platform is coated with a thin layer of liquid plastic.

A UV laser hits dynamic mirrors which direct the UV energy downwards across the build platform, curing the liquid resin in precise patterns one cross-section at a time. After each layer is cured, the build platform retracts into the bath of liquid while a recoater blade evenly distributes the resin across each new layer.

Stereolithography also requires build supports which are removed manually by hand, meaning areas that require support be accessible. Stereolithography support material is the same material as the final part.

Unlike PolyJet, Stereolithography parts do not fully cure during build. During printing, the resin within the chamber can become trapped within the part or pool in certain part features, reabsorbing into the part causing bloating and design distortion. Therefore, after a build is complete, excess resin is drained and supports are removed.

The part then enters a UV oven to complete curing. Being that Stratasys Direct has been building SLA parts almost since the industries birth means that we know how to build and post-process SLA parts backwards and forwards.

Five foot tall 3d printed SLA superhero

What Stereolithography Applications Can I Make? 

Stereolithography is perhaps best known for its ability to build mostly hollow parts with a thicker outer shell and a honeycomb interior. The most common application for hollow Stereolithography parts is investment casting patterns, where the SLA part is used to create a ceramic shell to then pour liquid material into, such as liquid metal. 

Additional common applications for Stereolithography include large entertainment models, prototypes, and master patterns for cold or low-temperature molds. SLA parts can be fully painted in-house to create display pieces, as well as individual parts can be bonded together and then painted to produce large models like our five-foot (5' ft) friend pictured left.

Stereolithography Finishing Experts

Our finishing expertise takes your 3D-printed prototype and transforms it into a replica of your finished product. Any surface look is achievable with our expert finishers. Custom finishing, texture, color, artwork, EMI/RFI shielding, plating, and other functional coatings can bring additional value to prototyping and models.

Materials for 3D Printing Parts with Stereoli -thography

SDM Material

Somos® WaterClear Ultra 10122

A clear and colorless material suited for lenses and see-through covers

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SDM Material

Somos® WaterShed XC 11122

Produces highly detailed parts with great clarity and water-resistance

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SDM Material

Somos® NeXt

Higher impact resistance than standard SL resins; Moisture resistance

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SDM Material

SC 1000P

Custom formulation ideal for low cost investment casting patterns

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Stereolithography Applications

Stereolithography Rapid Prototyping


Evaluate your design with a physical model and get to market faster with SLA.

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Stereolithography Concept Models


Build light-weight, cosmetic versions of your product with our hollow build method.

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Stereolithography Investment Casting Patterns


Our proprietary photopolymer and build style produces consistent patterns with better burnout.

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Stereolithography Rapid Prototyping

See What Makes Stereolithography So Popular

Stereolithography (SLA) produces large, highly-intricate parts with superb accuracy and finishes, making it one of the most popular and widely-used 3D printing technologies in the market today.

As one of the early pioneers of 3D printing technologies, Stratasys Direct has utilized and perfected stereolithography for more than 30 years. We’ve worked on hundreds of thousands of projects for companies in a wide range of industries, to create smooth, cosmetic prototypes, investment casting patterns, and lightweight concept models that attract attention. 

Our team of expert finishers adds color, texture, EMI/RFI shielding, electroplating, and more, to create stunning, attention-grabbing components with limitless size restrictions. That’s why stereolithography is one of the main go-to technologies in 3D printing.

General questions? Engineering questions? Need help with your design?

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3D Printed Stereolithography SLA part for investment casting

Frequently Asked Questions About Stereolithography

What geometries are best suited for SLA?

Stereolithography is ideal for parts with small features that require tighter dimensional tolerances and smooth finishes. SLA is ideal for small to large prototypes.

What level of detail can be obtained with SLA?

Stereolithography at its finest resolution offers a layer thickness of 0.004" inch (0.101 mm). 

What is the minimum wall thickness for SLA?

We recommend a minimum wall thickness of 0.060" inches (1.5mm) as smaller walls may not hold up when it comes to support removal or media blasting. 

Can SLA-made components function as production parts?

Stereolithography is not generally considered suitable for production applications because the photo-reactive resins used in the process do not remain stable under long exposure to UV light. However, SLA is often used to make precise investment casting patterns to create end-use metal parts.

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