Stereolithography Prototype, SLA Prototyping

Stereolithography 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 suited to production of 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

Technical Overview of Stereolithography Rapid Prototyping

To create a 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.

Stereolithography Rapid Prototype Equipment and Resins

• (2) SLA 3500 Systems
• (2) SLA-7000 Systems
• (2) Viper si² SLA Systems

Stereolithography (SLA) FAQ

What does SLA mean?

SLA is an acronym that stands for Stereolithography Apparatus

What material does stereolithography prototyping use?

The resins used in our SLA machines are photosensitive epoxy polymers. Currently, ProtoCAM employs four stereolithography resins in our six machines. WaterClear Ultra 10122, 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 is can be heat treated for higher heat deflection temperatures. The Accura 25 resin 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 0.0015" 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?

We have made a graphical guide that should help you. 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.

How does ProtoCAM price parts?

Projects typically range from $195 to $495. 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.

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.

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?

Level	Finish	Description
Level 1	Strip and ship	Remove supports No sanding
Level 2	Standard finish	Remove supports Lightly sand to 150 grit Bead blast
Level 3	Foundry pattern	Remove supports Sand to 220 grit Remove ~95% of the build lines
Level 4	Mold ready	Remove supports Sand to 320 grit Remove ~100% of the build lines Prime and putty
Level 5	Presentation	Remove supports Sand to 320 grit Remove ~100% of the build lines Prime, putty, and paint Matte gloss
Level 6	Clear coat	Remove supports Lightly sand support surface to 320 grit Clear coat
Level 7	Water clear	Remove supports Sand to 600 Remove ~100% of the build lines Clear Coat

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 our page on transfer details and the data formats we accept. Please consider using our Online Quotation form.

Contact ProtoCAM for Stereolithography Rapid Prototyping