SLA resin 3D printing: how it works, costs and design rules

Stereolithography cures liquid resin with a laser or light source, one thin layer at a time. It gives the smoothest and most detailed printed plastic parts: visual prototypes, moulds, dental and medical models.

Typical tolerance

±0.1–0.2 mm

Quantities

1 to a few hundred

Lead time

2–7 working days

Materials

Standard, tough, flexible, high-temperature, castable and clear resins

How it works

A build platform dips into a resin tank and each layer is cured by light. After printing, parts are washed in solvent and post-cured under UV light.

Benefits

• Smooth surfaces and very fine detail.
• Clear and transparent parts possible.
• Good for master patterns for casting and moulding.

Limitations

• Resins are more brittle than thermoplastics and can degrade in sunlight.
• Support marks need finishing.
• Hollow parts need drain holes.

What drives the cost

• Resin volume and build height.
• Specialty resins.
• Post-processing such as sanding and painting.

Design rules

• Walls at least 0.6–1 mm.
• Add drain holes of at least 3.5 mm to hollow sections.
• Avoid large flat areas parallel to the build plate.

Preparing your STEP file

• Export STEP; the service will orient and support it.
• Mark cosmetic faces where support marks are not acceptable.

See also the full STEP export checklist and the comparison of all processes.