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Stereolithography Prototype, SLA Prototyping

 

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Stereolithography reproduction of the Liberty BellStereolithography is the heart of ProtoCAM's rapid prototyping service, turning your 3D CAD drawing into a solid object.  Most stereolithography prototyping can be completed in as little as 1 to 2 days, with larger projects typically completed in under 5 days.  Stereolithography prototypes can be used as master patterns for injection molding core and cavity inserts, thermoforming, blow molding, and various metal casting processes.

Key benefits of Stereolithography Rapid Prototyping

  • Time savings: ProtoCAM can fabricate your SLA prototype in less than two days
  • Cost savings: ProtoCAM prices stereolithography prototypes competitively
  • Tight tolerances
  • Epoxy resin is resilient enough to be used for testing
  • Stereolithography is well suited to small lot manufacturing of prototype or end-use parts
  • Stereolithography investment casting patterns allow rapid production of metal prototypes
  • Rapid prototyping allows you to get your products to market faster
Dyed stereolithography models of chess rook pieces

Technical Overview of Stereolithography Rapid Prototyping

To create an SLA rapid prototype, first a three-dimensional CAD part is "sliced" horizontally into cross-sections between 0.002" and 0.006" thick. The slices are fed to 3D Systems' Stereolithography Apparatus. Inside the stereolithography chamber of the apparatus, an ultraviolet laser traces the first layer of the part on a metal platen, submerged just below the surface of a vat of photo-sensitive polymer. Wherever the laser touches the liquid, it solidifies. Once the layer is traced, the platen sinks the thickness of a layer below the level of the liquid. A sweeper bar moves across the surface of the last layer, making sure there is the exact amount of resin on top. The next layer is then built upon the previous layer. In this manner the entire part is built from the bottom up, with the completed sections of the part remaining submerged.

See an animated video of the stereolithography prototyping process.

Stereolithography Rapid Prototype Equipment and Resins

ProtoCAM has a wide assortment of SLA machines, and uses a variety of resins:

ProtoCAM's list of Available Stereolithography Resins:
Resin Property Maximum Part Dimensions Data Sheet
Accura 25 Polypropylene-like, Snap fits 25.6" x 29.5" x 21.65" PDF
Accura 60 Polycarbonate-like, clear 25.6" x 29.5" x 21.65" PDF
WaterShed XC 11122 Clear, High humidity resistance 10" x 10" x 9.7" PDF
SL 5530HT High Temperature 20" x 20" x 22.6" PDF

Stereolithography (SLA) FAQs

What does SLA mean?
SLA is an acronym that stands for StereoLithography Apparatus.

What material does stereolithography rapid prototyping use?
The resins used in our SLA machines are photosensitive epoxy polymers. ProtoCAM uses a variety of stereolithography resins in our machines. WaterShed 11122XC, the resin run in our Viper si2 machines, is untinted and can result in clear prototypes, given a Level 6 finish. The ProtoGen 18420 resin can be heat treated for higher heat deflection temperatures. Accura 25 is a white polypropylene-like resin designed for flexibility and snap fits. Accura 60 is a tough general purpose resin which can make translucent parts. Please see above for data sheets on these resins.

What tolerances can the stereolithography process hold?
Published tolerances of the models are +/-0.005" (0.127mm) for the initial inch, plus an additional 0.002" for each additional inch. If higher accuracy parts are needed, please contact us for a personal evaluation of your project.

How can I ensure that raised text on my prototype is legible?
The height of the text should be a minimum of 0.015" high, and the cross section of the text should be 0.015" or thicker. Text thinner than this cannot be reliably traced with the 0.010" thick laser beam. See our guide to raised text on stereolithography prototypes.

How does ProtoCAM price parts?
The following factors influence pricing:
  • Z-axis height
  • Volume
  • Complexity
  • Number of parts
The per-part price decreases as more parts are ordered until the point where there are too many parts to fit on a single run of one of our SLA machines. For a detailed explanation, see the ProtoCAM blog post Cost of Stereolithography Prototypes: Pricing Factors, How to Reduce Costs.

What size parts can be produced?
ProtoCAM's largest machine has a build envelope of 20" x 20" x 24"; however, multiple SLA prototypes can be glued together to create larger prototypes. For more on large prototypes, see the ProtoCAM blog post Prototyping Large Parts: Why We Have No Size Limitation.

What is the smallest feature that can be produced?
In standard resolution, the minimum feature in the X-Y plane is 0.010" and the minimum in the Z axis is 0.016". In high resolution, the 0.003" laser beam spot enables smaller features. ProtoCAM recommends a minimum wall thickness of 0.020" for prototype support.

What colors can be produced?
Stereolithography prototypes can be dyed or painted in virtually any color.

What kinds of finish options are available on SLA prototypes?
Finishes range from inexpensive natural parts to fully smoothed and painted show pieces. For more information, check our SLA Finish Levels page.

What temperatures can SLA prototypes withstand?
The standard epoxy resin has a heat deflection temperature of 144°F and high temperature epoxy resin has a heat deflection temperature of 392°F.

Can stereolithography prototypes be machined?
Yes, SLA prototypes can be drilled and tapped, milled, or put on a lathe.

Why should you use SLA versus another rapid prototyping technology?
The accuracy and surface finish of SLA are unsurpassed by any of the competing technologies, such as selective laser sintering (SLS).

How long does it take to build a part?
A typical order of prototypes is shipped out two days after receipt of order.  Most parts build in less than 12 hours.

How can I transfer my design information to ProtoCAM?
Please see the transfer details page and the data formats we accept. Please consider using our Online Quotation form.

Contact ProtoCAM for Rapid Prototyping, Stereolithography

Please contact us to discuss your stereolithography (SLA) prototype needs or to request a quotation.