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Stereolithography (SL)
You create solutions for the future; let us manufacture them. We specialize in on-demand digital manufacturing for both prototyping and end-use products. Here at Midwest Prototyping, you'll find industrial 3D printing and Cast Urethane operations. We have over 40 machines and offer over 40 materials. We look forward to getting your ideas made.

Table of Contents
What is Stereolithography?
Stereolithography (SL), also known as SLA, uses ultraviolet-sensitive liquid resins (photopolymers) that are instantly cured when activated by a UV laser. Then the parts are post-processed with additional UV and thermal treatments when necessary.
Stereolithography is a speedy and highly accurate process used most commonly for form and fit prototypes, master patterns, and large concept models. The combination of speed and design freedom offered by Stereolithography enables rapid iteration for new product development.
How does Stereolithography work?
We take your CAD file and input it into the machine, and the software breaks it down layer by layer. We also take into consideration the direction of the build and the placement of the supports. The Stereolithography machine uses an ultraviolet laser to draw each layer of the part onto the surface of the liquid thermoset resin. After each laser pass, the build platform moves down, and a bar moves across the surface, recoating the platform. This step is repeated until the build is complete.
Once finished, the platform is removed from the machine, and the parts are taken into a space where they are manually removed and cleaned using solvents. From there, parts are cured using a UV cycle to solidify the outer surface of the part. Once this step is finished, the parts are moved to the finishing department.

What are the ideal applications for Stereolithography?
- Large models, prototypes, and master patterns
- Investment casting parts
- Low-volume production for complex geometries
Stereolithography Capabilities at Midwest Prototyping
OEM:
3D Systems, RPS
Max Build Area:
31 in. x 31 in. x 23 in.
Lead Time:
1 – 2 Days
Material:
3D Systems Accura: 25, 60, ABS Black, AMX Rigid Black, Xtreme, Xtreme White 200
DSM Somos®: 8120, BioClear, EvoLVe, PerFORM, Taurus, WaterClear Ultra 10122, WaterShed Black, WaterShed XC 11222
Tolerances:
+/- .005 in. for the first inch and +/- .0015 in. for each additional inch
Layer Thickness:
Normal resolution layer thickness is .004 in. and minimum feature size is .012 in. High resolution layer thickness is .002 in. and minimum feature size is .006 in. (feature size is dependent on geometry).
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Which Stereolithography Materials does Midwest Prototyping Offer?
Material
Description
Key Characteristics
More Information
Accura 25 looks and feels like molded polypropylene with high flexibility, shape retention, and feature resolution.
- White
- High Resolution/High Detail
- Flexible
- Durable
- Good For Snap Fits
Accura 60 looks and feels like molded polycarbonate with clear rigidity and strength.
- Clear/ Translucent
- High Resolution/High Detail
- Rigid
Accura ABS Black creates strong parts with minimal finishing to replace CNC-machined or molded ABS parts.
- Black
- High Resolution/High Detail
- Rigid
- Impact Resistant
Accura AMX Rigid Black is an industrial resin with production-grade mechanical properties.
- Black
- High Strength
- High Resolution/High Detail
- Rigid
- UV Stability
- Good For Snap Fits
- Biocompatible*
- Moisture Resistant
Accura Xtreme is durable and accurate and can replace CNC-machined polypropylene and ABS.
- Grey
- High Resolution/High Detail
- Rigid
- Good For Snap Fits
Accura Xtreme White 200 is durable and breakage resistant and can replace CNC-machined polypropylene and ABS.
- White
- High Resolution/High Detail
- Rigid
- Good For Snap Fits
Somos® 8120 is a high-speed liquid photopolymer that produces flexible, high-impact strength, accurate parts.
- Clear/Translucent
- High Resolution/High Detail
- Rigid
- Good For Snap Fits
Somos® BioClear creates translucent and accurate surgical guides and models to prepare for surgical procedures.
- Clear/Translucent
- High Strength
- High Resolution/High Detail
- Biocompatible*
- Chemical Resistant
- Moisture Resistant
Safety Data Sheet
Somos® EvoLVe is a durable material that produces accurate, high-detailed parts and has been designed for easy finishing.
- White
- High Strength
- High Resolution/High Detail
- Good For Snap Fits
Somos® PerFORM produces strong, stiff, high temperature resistant composite parts.
- Off-White
- Heat Resistant
- High Resolution/High Detail
- Rigid
Somos® Taurus creates accurate parts with exceptional surface quality and isotropic mechanical properties.
- Charcoal
- Heat Resistant
- High Strength
- High Resolution/High Detail
Somos® Watershed creates optically clear parts with smooth finishes.
- Clear/ Translucent
- High Resolution/High Detail
- Rigid
Somos® WaterShed Black is a solution to build rigid, moisture resistant, and tough parts while eliminating the need for painting.
- Black
- Rigid
- Chemical Resistant
Somos® WaterShed XC 11122creates optically clear parts with smooth finishes.
- Clear/ Translucent
- High Resolution/High Detail
- Rigid
*Special processing may be required. Please notify us of any biocompatibility needs.
Compare Materials
Best Practices for Designing Parts for Stereolithography at Midwest Prototyping.
Feature
Measurement
Supported Walls
.02 in
Unsupported Walls
.04 in
Supports & Overhangs
Base Support Otherwise 45 Degrees
Embossing & Engraving
Width: .016 in, Height/Depth: .016 in
Horizontal Spans
.08 in
Holes & Openings
.02 in
Connecting & Moving Parts
.03 in
Escape Holes
.04 in
Minimum Features
.008 in
Pin Diameter
.03 in
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What Are the Finishing Levels at Midwest Prototyping?
Level
Process
Description
1
Supports removed and support faces lightly sanded
Standard finish: supported surfaces appearing dull and non-supported surfaces appearing glossy. Parts will have visible layer lines.
2
Supports removed, support faces lightly sanded, and entire part bead blasted
Even surface finish: gloss removed from non-supported surfaces to create a more consistent finish. Parts will have visible layer lines.
2 +
Supports removed, support faces lightly sanded, cosmetic surfaces sanded to 180 grit, and entire part bead blasted
Functional finish: removes some layer lines. Parts have a light texture from sanding.
3
Supports removed, support surfaces lightly sanded, cosmetic surfaces sanded to 320 grit, and entire part bead blasted
Show quality finish: removes layer lines from cosmetic surfaces. This finish is recommended for priming, painting, and urethane mold masters.
4
Supports removed, support surfaces lightly sanded, cosmetic surfaces wet sanded to 600 grit
Highest quality finish: recommended only for plating and optically clear parts.