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SLA RESIN PRINTING

SLA (stereolithography) uses UV light to cure liquid resin layer by layer, producing parts with ultra-fine detail and smooth surface finishes unmatched by filament-based printing. We print SLA on the Formlabs Form 4, with a range of 14 engineering and specialty resins.

THE PROCESS

HOW SLA PRINTING WORKS

SLICING

Your 3D model is sliced into ultra-thin layers (25-100 microns). Support structures are generated for overhangs.

UV EXPOSURE

A UV LCD screen selectively cures each layer of liquid resin in the vat, hardening it into solid plastic.

LAYER BUILD-UP

The build plate lifts between each layer. The process repeats, building the part upside-down from the plate.

POST-PROCESSING

Parts are washed in isopropyl alcohol to remove uncured resin, then UV-cured in a curing station for full hardness.

CHARACTERISTICS

STRENGTHS & LIMITATIONS

STRENGTHS

• Ultra-fine detail — 25-100 micron layer resolution

• Smooth surface finish with virtually no visible layer lines

• Fully solid prints — excellent dimensional accuracy

• Sharp edges and crisp text reproduction

• Ideal for miniatures, jewellery masters, and dental models

• High stiffness and hardness in standard resins

LIMITATIONS

• Brittle under impact — resin cracks rather than flexes

• Smaller build volume than FDM (200 x 125 x 210mm)

• UV degradation — parts yellow and weaken in direct sunlight

• Requires post-processing (wash + UV cure) for every print

• Higher cost per part than FDM for equivalent volume (printed alone — parts uploaded together share a build plate)

• Limited material variety compared to FDM filaments

MATERIALS

RESIN TYPES

STANDARD RESINS

PROPERTIES

Crisp detail, smooth finish, rigid

BEST FOR

Visual prototypes, miniatures, display and concept models

General-purpose Formlabs resin in Grey, Black, White or Clear, plus draft-speed Fast Model. Standard Clear polishes to near-transparent for light pipes and visual parts. Rigid and detailed, but brittle under impact — not for parts that must flex.

ENGINEERING RESINS

PROPERTIES

Functional strength — tough, stiff, heat- or impact-resistant

BEST FOR

Snap-fits, jigs, enclosures, brackets, living hinges, heat-exposed parts

Tough 1500 (polypropylene-like) and Tough 2000 (ABS-like) for durable working parts, Rigid 4000 (glass-filled) for stiffness, Durable for low-friction hinges, High Temp for heat deflection up to 238°C, Flexible 80A for rubber-like parts, and ESD for electronics fixtures.

SPECIALTY RESINS

PROPERTIES

Exotic capabilities — silicone, flame-retardant, castable, ultra-stiff

BEST FOR

Seals & gaskets, casting patterns, short-run tooling, certified enclosures

Special-order resins we bring in per job: Silicone 40A (true platinum-cure silicone, 40 Shore A), Flexible 50A (very soft), Castable Wax (clean burnout for investment casting), Flame Retardant (UL 94 V-0), and Rigid 10K (ceramic-stiff tooling resin).

Not sure which resin fits your part? See our resin selection guide for the full range and a decision tree.

POST-PROCESSING

REQUIRED FINISHING STEPS

WASH

3-10 MINUTES

Parts are cleaned in isopropyl alcohol (IPA) to remove uncured resin from the surface. This is essential — skipping it leaves a tacky, sticky finish.

UV CURE

5-30 MINUTES

Washed parts are placed in a UV curing station to reach full hardness and mechanical properties. Without curing, parts remain soft and weak.

SUPPORT REMOVAL

5-15 MINUTES

Thin support structures are clipped away with flush cutters. Support marks can be sanded smooth for a clean finish.

All SLA prints from Bicester3D include wash and UV cure as standard. Our pricing reflects the additional post-processing time and materials required. Plate-level costs — machine time, wash and cure — are charged once per build plate, not per part.

APPLICATIONS

WHEN TO CHOOSE SLA

MINIATURES & FIGURINES

Tabletop gaming miniatures, collectible figurines, and small sculptures where fine detail is critical.

JEWELLERY & MASTERS

Casting masters and patterns for jewellery production. Sharp edges and smooth surfaces reduce finishing work.

DENTAL & MEDICAL MODELS

Dental aligners, surgical guides, and anatomical models requiring precise dimensional accuracy.

VISUAL PROTOTYPES

Product mockups and presentation models where surface finish matters more than mechanical performance.

SMALL ENCLOSURES

Thin-walled housings and enclosures for electronics where precise fit and clean aesthetics are required.

ARTISTIC & DECORATIVE

Detailed ornaments, architectural models, and art pieces that benefit from the smooth, injection-mould-like finish.

GET AN SLA QUOTE

Upload your model and select SLA to get an instant resin printing quote. Includes wash and UV cure as standard.

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