Our Stereolithography (SLA) design guidelines help engineers design parts with high resolution, smooth surface finish, and precise feature detail. This guide covers critical considerations including wall thickness, minimum feature size, support strategy, part orientation, and post-processing so parts print accurately and maintain dimensional stability for detailed prototypes and high-precision end-use components.
Build Volume
1500 x 750 x 550 mm
General Tolerance
±0.25% (min ±0.25 mm)
Min. Wall ThicknessMinimum Wall Thickness
0.8 mm
Min. Hole DiameterMinimum Hole Diameter
0.5 mm
Stereolithography (SLA) uses a high-precision UV laser to cure liquid photopolymer resin layer-by-layer into solid parts. This advanced resin-based technology excels at producing highly detailed prototypes and functional parts with exceptional surface finish and dimensional accuracy.
These SLA design guidelines outline critical considerations for wall thickness, fine details, clearances, and resin behavior. Following these proven best practices ensures your parts achieve superior surface quality, precise dimensions, and optimal structural integrity for both prototyping and low-volume production.
1500 x 750 x 550 mm (59.1 x 29.5 x 21.7 in)
SLA offers the largest build volume in our facility, capable of producing parts up to 59 inches long in a single build. Parts larger than this can be printed in sections and assembled.
NoteThis is one of the largest SLA build volumes available for industrial applications.
Standard parts: ±0.25% (min ±0.25 mm), Large parts: ±0.4% (min ±0.5 mm)
Standard parts (10" x 10" x 10" or smaller): ±0.25%, with a lower limit of ±0.25 mm. Large parts (10" x 10" x 10" or larger): ±0.4%, with a lower limit of ±0.5 mm.
NoteTolerances as tight as +/- 0.2 mm (+/-0.005") can be achieved on request. If tighter tolerances are required, please provide an engineering drawing when requesting a quote.
50 or 100 microns
Parts are printed at the standard 100 micron layer thickness (HD) unless our high definition (XHD) option is chosen, at 50 microns. Keep in mind that our higher resolution option also doubles the print time.
CriticalHigher resolution (50 micron) layers significantly increase print time but provide superior detail resolution.
High Definition
Parts have a smooth and uniform surface finish. Very small layer lines may still be visible, especially on surfaces at a low angle relative to the build plate.
TipSLA provides the smoothest surface finish among all additive manufacturing technologies.
Large, thin-wall areas are at risk of deformation. In general, follow wall design rules for injection molding to achieve a more uniform and consistent part.
0.8 mm (0.031 in)
Supported walls are connected to two or more sides and are thick enough to support the model.
NoteThicker walls provide better structural integrity and reduce the risk of warping during curing.
1.5 mm (0.059 in)
Unsupported walls are connected on only one side or edge.
CriticalUnsupported walls thinner than 1.5mm may sag or warp during the printing process.
2 mm (0.079 in)
The minimum pin size depends on a combination of parameters such as; part orientation, nozzle diameter, and length of the pin.
Recommendations
Intricate details and text are often the reason for choosing this technology over others. Try to place fine details away from overhanging faces that require support, since touchpoints can interfere with intricate geometry.
Minimum Width and Depth: 0.5 mm (0.02 in)
Engraved details are recessed features on your model. Making these too small can result in closed gaps and loss of detail.
Recommendations
Minimum Width and Depth: 0.5 mm (0.02 in)
Embossed details are raised features on your model. These usually resolve better than engraved details. Extruded text should have a wall thickness of at least 1.5mm (0.059") when printed flat, and 2mm (0.079") when printed vertically.
TipRaised features generally print more reliably than recessed ones due to the layer-by-layer nature of SLA.
Minimum point size: 14pt
Bold, sans-serif fonts typically resolve better at smaller sizes.
Recommendations
The mechanical performance of printed assemblies is sensitive to variables such as print orientation, layer height and machine tolerances. It is best to test and refine any mated parts before committing to a full production run.
0.5 mm (0.02 in)
Clearance is the distance between two moving parts on hinges, joints, mating parts, etc. We require a minimum of 0.5mm on all sides.
CriticalParts with insufficient clearance may fuse together during the curing process.
0.1 mm (0.004 in)
For a tight press fit, add a small offset, and chamfer the leading edge to ease entry. We recommend printing an initial test part to dial in dimensions.
Recommendations
Minimum: 0.6 mm (0.024 in)
It is possible to print mechanical linkages (eg. hinges, chains) already assembled. When designing for this scenario, clearance should be at least 0.6mm to prevent these features from fusing during the build.
TipSLA is excellent for printing complex assembled mechanisms in a single build.
Hole accuracy can vary depending on print orientation, thickness of surrounding material and support structures. For tight tolerances, consider printing center marks and post-machining them instead.
0.5 mm (0.02 in)
Depending on orientation, circular holes can resolve as ovals – if higher accuracy is required, printing the hole smaller and then drilling it out is recommended.
NoteVertical holes print more accurately than horizontal holes due to layer adhesion characteristics.
0.5 mm (0.02 in)
Gaps or slots can fuse if made too narrow, and support material may be difficult to remove. If possible, orient gaps along the xy-plane for highest accuracy.
Recommendations
4 mm (0.157 in)
Escape holes are essential for removing unsintered powder from hollow or enclosed parts. A minimum hole diameter of 4 mm (0.157") is required when using a single escape hole to allow efficient powder removal.
TipFor larger parts exceeding 50 mm x 50 mm x 50 mm, at least two escape holes are recommended, each with a minimum diameter of 2 mm (0.078").
Part geometry can be optimized for 3D printing to reduce material usage, increase strength and rigidity, and take advantage of machine capabilities.
Design Recommendations
Fillets can be used to reduce stress concentrations and increase the strength of your part. When designing fillet features across inside and outside corners, it is best to have them share a common center point in order to maintain a consistent wall thickness.
Recommendations
Design Recommendations
Bosses and ribs are an effective way to add strength and stiffness to a part while keeping material consumption to a minimum, this can also reduce build time and use less support material.
Recommendations
SLA Printing
Thin supports are used to stabilize the part during printing. Supports are removed by our technicians and any remaining defects and are sanded down to leave no visible imperfections.
NoteSLA requires support structures for overhangs and bridges, but these are carefully removed and finished.
SLA Printing
Parts are always printed solid. Infills are not applicable for SLA.
NoteSLA parts are solid by nature, providing consistent mechanical properties throughout.
Threads and inserts can increase functionality of your parts, but keep in account that printed threads will wear down through repeated cycles of assembly and disassembly, while heat set inserts can potentially deform or cause imperfections on part finish due to the heat processes of installation.
SLA Guidelines
We recommend M6 thread sizes or larger, and use thread profiles designed for plastics. The rough surface produced from SLA printing will result in increased friction with connecting thread parts. We recommend using an offset of 0.5mm to compensate for thermal shrinkage.
Recommendations
SLA Post-Processing
Design parts with holes sized for tapping, or center marks for drilling a pre-tapped hole. Tapping removes material, puts pressure on the surrounding geometry, so make sure there is enough material surrounding the tapped hole.
CriticalEnsure adequate wall thickness around tapped holes to prevent cracking during the tapping process.
SLA Applications
Heatset inserts cannot be installed with photopolymers since they are thermoset plastics, so design holes such that inserts can be glued into place.
Recommendations
While printed parts are highly functional and accurate, there are a variety of ways to modify them after printing to enhance durability or aesthetics.
SLA Post-Processing
Parts too big to fit on the print tray can be split in CAD and printed in multiple parts, then glued or press fit. Use joinery features, such as tongue and groove, to ensure the sections are aligned and bond tightly.
Recommendations
SLA Machining
Parts can be machined to tighter tolerances using traditional or CNC subtractive manufacturing equipment.
TipSLA parts machine well due to their homogeneous structure and lack of internal stresses.
SLA Finishing
SLA parts have an ultra smooth surface finish and can be easily sanded, primed, and painted to achieve an excellent surface finish. Parts can also be dyed at low temperatures using synthetic dyes.
Recommendations
SLA Post-Processing
Not applicable for SLA.
NoteSLA parts already have excellent surface finish that typically does not require vapor smoothing.
