Rather than extruding thermoplastic in layers, stereolithography (SLA) 3D printers cure layers of liquid resin with a laser on the build platform to create solid models.
Resins are liquid polymers that mimic the performance of thermoplastics or have a one-use purpose, like jewellery casting.
The significant advantage of SLA is the laser is not restricted by the physical motion of a mechanical print head and produces a finer surface quality with greater precision, opening the door to manufacturing with tight tolerances.
Formlabs is the best-known maker of SLA 3D printers with proprietary resins, but they have improved the technology in recent years with low force stereolithography (LFS) for higher print quality and accuracy.
LFS introduces a flexible resin tank and linear illumination to reduce peel forces, producing snap-off support structures that pull away cleanly.
This article explores how to choose the best Formlabs 3D printing resin for your projects with expert advice.
Best resin for rapid prototyping
The best resin for rapid prototyping is Draft Resin V2 because it prints up to four times faster than standard resins, supporting print resolutions up to 200 microns and letting you print with layers that are 33% thinner.
Draft Resin V2 makes sense for initial prototypes, rapid design iterations, and high throughput parts. It does not require UV light or heat curing, but heating to 60 °C for five minutes improves the tensile strength.
Choose Draft Resin if you need fast print speeds and moderate surface quality for prototypes and concept models.
Best resins for model making and general use
Whether you want to print functional prototypes or detailed models, the best resins are found in Formlabs’ standard resin range. This includes Grey Resin, Clear Resin, White Resin, and Black Resin, which offer the same performance.
Standard Resins have 65 Mpa tensile strength and a flexural modulus of 2.2 GPa, making them strong and relatively rigid when printed in thick layers. They print at 100, 50, and 25 microns, giving you lots of scope for detail.
Choose standard resins if you want to balance print speed, strength, and quality without sacrificing dimensional accuracy.
Best resins for functional models
Functional models are best printed with Grey Pro Resin, which is formulated to withstand deformation under load. Tougher and more flexible than Standard Resins, Grey Pro offers 13% elongation compared to the standard resin’s 6%.
Another option is Tough 2000 resin, the strongest and stiffest material in the Tough resin family. It produces solid and stiff prototypes, idea for jigs and fixtures requiring minimal deflection, simulating the strength and stiffness of ABS.
Best resins for tough and durable parts/models
If the ABS-like qualities of Tough 2000 Resin are too extreme, Tough 1500 Resin replicates the performance and polypropylene (PP). It’s best for parts and prototypes that need to bend and quickly return to shape without deformation.
Another option is PU Rigid 1000 Resin, a polyurethane photopolymer designed for 3D printing semi-rigid and tough polyurethane parts. Another PU resin, PU Rigid 650, delivers high impact resistance and maintains dimensional accuracy under load.
Should you want to print squeezable prototypes and models like bottles and casings, the best resin is Durable Resin. This mimics the performance of polyethene (PE) and has the low-friction surface necessary for consumer products.
Best resins for ESD-safe applications
The only ESD-safe material in the Formlabs resin catalogue is ESD Resin, which offers similar performance to Grey Resin. ESD Resin produces static-dissipative parts that repel dust and powder, making it ideal for electronics.
ESD Resin is the perfect choice for custom trays for component handling, storage, and anti-static prototype and end-use components across most electrical applications.
Best resins for flexible and elastic parts
Flexible 80A Resin is a semi-rigid soft-touch material formulated to withstand repeated deformation and cycling. It’s the stiffest flexible material Formlabs makes, ideal for models that require rubber-like qualities.
If you need a less stiff flexible material, try Elastic 50A Resin, which mimics the performance and feel of silicone. It’s the best resin for models and parts that will bend, stretch, compress, and hold up to repeated cycles without tearing.
Best resins for casting (jewellery, metalwork)
Formlabs offers two resins for casting: Castable Wax Resin and Castable Wax 40 Resin.
Castable Wax 40 Resin is 40% wax-filled, while Castable Wax Resin is 20% wax-filled. The higher the wax fill, the easier the printing experience. Castable Wax Resin is best for highly detailed jewellery, and Castable Wax 40 Resin for jewellery components.
Both resins can be used with a standard burnout schedule for most jewellery designs and capture exceptional detail on the print bed.
Best resins for biomedical models and parts
Formlabs produces four biomedical resins compatible with common solvent disinfection and sterilisation methods. These resins are BioMed Black Resin, BioMed Amber Resin, BioMed Clear Resin, and BioMed White Resin.
BioMed Black Resin is a rigid matte black material for biocompatible applications requiring long-term skin contact or short-term mucosal membrane contact. BioMed White Resin offers similar performance but is opaque.
BioMed Amber Resin and BioMed Clear Resin have light transmittance for producing rigid transparent parts. BioMed Clear Resin has found many uses for moulds, jigs, fixtures, adapters, and medical devices.
Find out more
For help choosing the right resin for 3D printing, please get in touch with the team at 01765 694 007, email [email protected], or you can book an appointment with Elaine