Stereolithography3D Printing Design Guidelines

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.

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.

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.

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.

Supported walls are connected to two or more sides and are thick enough to support the model.

Unsupported walls are connected on only one side or edge.

The minimum pin size depends on a combination of parameters such as; part orientation, nozzle diameter, and length of the pin.

Engraved details are recessed features on your model. Making these too small can result in closed gaps and loss of detail.

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.

Bold, sans-serif fonts typically resolve better at smaller sizes.

Clearance is the distance between two moving parts on hinges, joints, mating parts, etc. We require a minimum of 0.5mm on all sides.

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.

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.

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.

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.

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.

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.

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.

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.

Parts are always printed solid. Infills are not applicable for SLA.

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.

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.

Heatset inserts cannot be installed with photopolymers since they are thermoset plastics, so design holes such that inserts can be glued into place.

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.

Parts can be machined to tighter tolerances using traditional or CNC subtractive manufacturing equipment.

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.

Not applicable for SLA.