SLA PROTOTYPES
STEREOLITHOGRAPHY
ABOUT SLA PROTOTYPES
Stereolithography (SLA) is an additive manufacturing process.
SLA parts have the highest resolution and accuracy. The clearest details and the smoothest surface finish of all plastic 3D printing technologies. It meets tight tolerance requirements as well as being truly suited for complex design. SLA also offers a speed advantage when you require a variety of functional prototypes or quick access to casting patterns.
Great for concept models, presentation models, master patterns, snap fit assemblies, form-fit-function testing, wind-tunnel test models, and design verification prototypes.
Our SLA process utilizes a vat of liquid photopolymer resin cured by an ultra violet (UV) laser to solidify the pattern, layer by layer, from the bottom-up to create a solid 3D prototype from 3D CAD data.
Our SLA Process
Versadyne’s SLA process utilizes a bottom-up vat polymerization technology developed by Charles W. Hull of 3D Systems Inc. All our SLA prototypes are generated on 3D Systems’ Viper si²® SLA system. These machines are versatile industrial level 3D printers which generate professional level parts with the highest accuracy, smooth surface finish, good optical clarity and thin, straight walls.
This system generates a fully dense high quality part without warpage. This allows us to offer, quickly and economically, a full range of build resolutions, materials, finishing and secondary process options.
Our dedicated staff has decades of experience not only in prototyping but also in manufacturing processes. We welcome discussions and requests for any special needs or requirements.
SLA Prototype Specification Guidelines
Outlined below are the options which need to be specified when ordering an SLA prototype. This includes materials, resolutions, and finishing.
DSM Somos 9120
Produces robust, functional and accurate parts. 9120 exhibits superior fatigue properties, strong memory retention and high quality up-facing and down-facing surfaces. It also offers a good balance of properties between rigidity and functionality. This material is useful in creating parts for applications where durability and robustness are critical requirements (i.e. automobile components, electronic housings, medical products, large panels and snap fit parts). This material was designed to simulate polypropylene. Appearance: Translucent off white.
DSM Somos Watershed XC 11122
Produces strong, tough, water-resistant ABS-like parts. 11122 is nearly colorless. It offers many properties that mimic traditional engineering plastics including ABS and PBT. This makes the material ideal for many applications in the automotive, medical, and consumer electronics markets and include lenses, water flow analysis, RTV patterns, durable concept models, and wind tunnel testing. Appearance: Clear – near colorless.
Material Selection Options
Photocurable Resin
SLA Resolution Explained
Items to consider when determining the build resolution desired:
- The thinnest section in the X-Y plane throughout the part, generally wall thickness or surface features.
- The thinnest section in the Z plane. This includes the depth of engraved or raised lettering.
- Overall size of the part.
- The final appearance required for the part.
As a general rule, the higher the resolution, the more costly it becomes to create the part.
This is a direct result of the amount of time it takes to build the part.
With 3D Systems Viper si² machines, there are two factors for resolution:
- The thickness of each layer or slice.
- The diameter of the laser spot used to draw each layer.
These two combined will determine the smallest feature or thinnest wall a given resolution will create. The diameter of the laser spot determines the minimum cross section and the minimum feature size. As a general rule, the finer the build resolution, the more costly it becomes to create the part. This is a direct result of the time it takes to build the part.
SLA Resolution Selection Options
The table below provides detailed information on the four different resolutions available as well as important design considerations.
SLA Resolution Guidelines and Capabilities
| Resolution: | Layer Thickness | Spot Size |
| Low | 0.006″ (0.1524mm) | 0.010″ (0.2540mm) |
| Standard | 0.004″ (0.1016mm) | 0.010″ (0.2540mm) |
| High | 0.002″ (0.0508mm) | 0.010″ (0.2540mm) |
| Ultra-High | 0.002″ (0.0508mm) | 0.003″ (0.0762mm) |
| Resolution: | Minimum Cross Section | Minimum Hole Size |
| Low | 0.012″ (0.3048 mm) | 0.025″ (0.635mm) |
| Standard | 0.012″ (0.3048 mm) | 0.025″ (0.635mm) |
| High | 0.012″ (0.3048 mm) | 0.020″ (0.5080mm) |
| Ultra-High | 0.005″ (0.1270mm) | 0.015″ (0.3810mm) |
| Resolution: | Minimum Feature Size |
| Low | X-Y Axes: 0.012″ (0.3048mm) Z Axis: 0.012″ (0.3048mm) |
| Standard | X-Y Axes: 0.012″ (0.3048mm) Z Axis: 0.012″ (0.3048mm) |
| High | X-Y Axes: 0.012″ (0.3048mm) Z Axis: 0.010″ (0.2540mm) |
| Ultra-High | X-Y Axes: 0.004″ (0.1016mm) Z Axis: 0.010″ (0.2540mm) |
| Resolution: | Tolerances |
| Low | X-Y Plane: ±0.005″ for first ¼” plus ±0.002″ for every inch thereafter. Z Plane: ±0.010″ for first inch plus ±0.003″ for every inch thereafter. |
| Standard | X-Y Plane: ±0.005″ for first ¼” plus ±0.002″ for every inch thereafter. Z Plane: ±0.010″ for first inch plus ±0.003″ for every inch thereafter. |
| High | X-Y Plane: ±0.003″ for first 1/10″ plus ±0.0015″ for every inch thereafter. Z Plane: ±0.005″ for first inch plus ±0.0015″ for every inch thereafter. |
| Ultra-High | X-Y Plane: ±0.003″ for first 1/10″ plus ±0.0010″ for every inch thereafter. Z Plane: ±0.005″ for first inch plus ±0.0015″ for every inch thereafter. |
| Resolution: | Maximum Part Size* |
| Low | 10″ x 10″ x 10″ 254mm x 254mm x 254mm |
| Standard | 10″ x 10″ x 10″ 254mm x 254mm x 254mm |
| High | 10″ x 10″ x 10″ 254mm x 254mm x 254mm |
| Ultra-High | 10″ x 10″ x 10″ 254mm x 254mm x 254mm |
| *For parts larger than 10″ x 10″ x 10″, we will section the part and add features to allow assembly of the final part. We assemble and bond the parts together utilizing an industry specific UV cure bonding agent. Please contact us if you would like additional detail. | |
Strip & Ship
Part is cleaned & post cured. All supports are removed. Support surfaces may still show some support stubble.
Basic
Part is cleaned & post cured. All supports are removed. Support surface is lightly sanded to remove stubble.
Standard
Basic Finish
+ Part is sanded to remove the heaviest of the stair stepping (build lines) on the exterior or outside of the part where possible.
Quick Primed
Basic Finish (stair stepping/layer lines are not removed)
+ Primer is applied for a ready to paint surface. Unless otherwise requested, only the outer surfaces are primed.
Primed
Basic Finish
+ stair stepping/layer lines are removed on the outside (exterior) of the part where possible
+ Primer is applied for a ready to paint surface. Unless otherwise requested, only the outer surfaces are primed.
Quick Paint
Basic Finish
+ Support surface is lightly sanded to remove stubble (stair stepping/layer lines are not removed)
+ Paint is applied as per customer supplied PMS color number or sample.
NOTE: If a multi-color model is required, a JPEG file or document depicting the paint scheme is preferred. Unless otherwise requested, only the outer surfaces are painted.
Presentation
Basic Finish
+ Part is sanded to remove all stair stepping (build lines) on the exterior or outside of the part
+ Paint is applied as per customer supplied PMS color numbers.
NOTE: If a multi-color model is required, a JPEG file or document depicting the paint scheme is preferred. Unless otherwise requested, only the outer surfaces are painted.
Quick Clear (XC 11122 Material Only)
Basic Finish
+ Support surface is lightly sanded to remove stubble (stair stepping/layer lines are not removed)
+ Clear coat is applied to produce a transparent part.
This results in a part with increased transparency but will not produce a part that is optically clear. Unless otherwise requested, only the outer surfaces have clear coat.
Presentation Clear
Basic Finish
+ Part is sanded to remove all stair stepping (build lines) on the exterior and on the interior where accessible.
+ Clear coat is applied to produce transparent parts.
Presentation Chrome
Basic Finish
+ Part is sanded to remove all stair stepping (build lines) on the exterior or outside of the part.
+ Our chroming process is applied (Chrome is applied via PVD). Clear coat is applied to prevent tarnish.
Presentation Texture
Basic Finish
+ Part is sanded to remove all stair stepping (build lines) on the exterior where accessible.
+ Texture and paint is applied to part as per customer instructions.
Standard SLA Finishing Options
These are our standard finishes. We welcome custom finishing requests.
SLA Design Considerations
You can design for the SLA process, however, it is more advantageous to design for the manufacturing process you will ultimately be using. Then make any small changes needed for the SLA process, if any.
So if you are making a plastic container which will be manufactured utilizing injection molding, please use injection molding design standards.
If you are unsure of the ultimate manufacturing process to be used, it is safe to use injection molding standards but keep in mind the tolerances shown below.
Bosses
Include bosses around holes in locations where threaded fasteners will be used to reduce the likelihood of bulging, distortion, and potential fracture. A minimum of 1 hole diameter for the wall thickness around the hole is a good starting point (e.g. if the hole is a M5 screw include a minimum 5mm of wall thickness around the hole).
Fillets
Fillets and radii are not required for SLA. However, adding fillets and radii help to reduce stress concentrations at corners and edges. Even a small radius can make a big difference.
Holes
Since the high viscosity of the resin used can pose challenges during the post-build process, try to avoid holes smaller than 0.005″. If your design requires them, please bring this to our attention when ordering your prototype.
Hollow Out Your Model
To reduce machine time and material cost, try to hollow out your model. Always include a drain hole or two to allow the release of the resin from the enclosed space.
Mating Parts and Assemblies
It is recommended to design at least a 0.010″ gap overall between any two mating faces in mating parts or assemblies.
Ribs and Gussets
Ribs and gussets are not required for SLA. However, adding ribs and gussets can help reduce and distribute stresses throughout the part and improve rigidity. To save on material, ribs and gussets can be designed to 75-80% of wall thickness.
Tolerances
Low Resolution Build Mode (6mil):
X/Y Planes: +/- 0.005″for the first quarter inch, plus +/- 0.002″ for every inch thereafter. Z Plane: +/- 0.010″ for the first inch, plus +/- 0.003 for every inch thereafter. Minimum linear feature size: under 0.020″ are at risk and under 0.010″ will not build. Minimum radial feature size: 0.025″
Standard Resolution Build Mode (4 mil):
X/Y Planes: +/- 0.005″ for the first quarter inch, plus +/- 0.002″ for every inch thereafter. Z Plane: +/- 0.010″ for the first inch, plus +/- 0.003″ for every inch thereafter. Minimum linear feature size: under 0.020″ are at risk and under 0.010″ will not build. Minimal radial feature size: 0.025″
High Resolution Build Mode (2 mil/10 spot):
X/Y Planes: +/- 0.003″ for the first 1/10 inch, plus +/- 0.0015″ for every inch thereafter. Z Plane: +/- 0.005″ for the first inch, plus +/- 0.0015″ for every inch thereafter. Minimum linear feature size: under 0.020″ are at risk and under 0.010″ will not build. Minimum radial feature size: 0.020″
Ultra High Resolution Build Mode (2 mil/3 spot):
X/Y Planes: +/- 0.003″ for the 1/10 inch, plus +/- 0.001″ for every inch thereafter. Z Plane: +/- 0.005″ for the first 1/10 inch, plus +/- 0.001″ for every inch thereafter. Minimum linear feature size: under 0.008″ are at risk and under 0.004″ will not build. Minimum radial feature size: 0.008″
NOTE: TOLERANCES MAY CHANGE DEPENDING ON PART GEOMETRY.
Wall Thickness
It is recommended that you utilize a uniform wall thickness.
Warping
Warping is not an issue in our parts which are produced on the Viper si² machines.
SLA Prototype Quote Submission
You will receive an e-mail confirming receipt of your request.
Files up to 20MB may be sent via e-mail to: Sales@Versadyne.net
