Accura ABS White (SL 7810) is a liquid photopolymer supplied by 3D Systems for 355 nm stereolithography platforms. The product is not a filled resin; it is a reactive liquid that forms an opaque white solid when scanned by the laser and subsequently post-cured. The material code SL 7810 identifies the specific formulation within the Accura family and should not be confused with ABS filament or injection-molding grades of acrylonitrile-butadiene-styrene. Liquid density at 25 °C is approximately 1.13 g/cm³, while cured solid density is approximately 1.20 g/cm³. Typical processing occurs on 3D Systems Viper si2, SLA 7000, iPro 8000, and ProX 800 systems, with layer thicknesses in the 0.05–0.15 mm range depending on build mode and part geometry. The resin is formulated for 355 nm exposure and is not directly interchangeable with 405 nm DLP or LED resins without recalibration.

Selection of SL 7810 is generally driven by a requirement for an opaque white prototype that approximates unfilled ABS in short-term tensile stiffness and surface detail while retaining SLA accuracy. Mechanical test data are generated from post-cured specimens built in the X–Y plane; Z-axis properties are lower because of interlayer polymerization boundaries. Design reviews must therefore specify build orientation before interpreting tensile or flexural values. The material exhibits a Shore D hardness of approximately 84 after recommended post-cure, which supports scratch resistance during handling but does not replicate the surface mechanics of textured or painted production ABS parts.

What Limits Dimensional Stability in SLA Builds with SL 7810?

Dimensional stability is controlled by photopolymerization conversion, post-cure shrinkage, and moisture uptake. Green-state parts removed from the platform before post-cure retain a lower crosslink density and can creep under load. The post-cure step raises the tensile modulus from its green-state value to the published range of approximately 2,300–2,500 MPa for ASTM D638 Type IV specimens. Flexural modulus under ASTM D790 is generally lower, with manufacturer-reported values near 2,000 MPa. The difference between tensile and flexural modulus reflects stress-state sensitivity of the crosslinked network and is relevant to snap-fit design because outer fibers in flexure may reach yield earlier than the uniaxial tensile curve would suggest. Dimensional accuracy is also affected by residual stress from high scanning overlap at corners and thick sections. Large flats should be supported with lattice structures and oriented at an angle to minimize part curl.

When processing SL 7810 on production SLA systems, the vat temperature is typically maintained between 30 and 32 °C. Recoat parameters must not be copied from other Accura resins because the resin has a unique critical exposure and recoat rheology. Photopolymer batch-to-batch variance may appear as a shift in required scanning energy, particularly if the resin has been stored beyond its recommended shelf life or contaminated with residual solvent. Operators often qualify a new lot with a small star-step or cantilever file before committing full-size builds. If a build failure generates cured debris, the resin should be filtered through a fine screen before reuse; particles retained in the vat can damage the recoat blade and produce line artifacts on the next build.

If the Part Sits Near a Heat Source or Under Mechanical Load

Heat deflection temperature for post-cured SL 7810 is reported under ASTM D648. The 0.455 MPa deflection temperature is commonly between 60 and 70 °C, while the 1.82 MPa deflection temperature is lower, typically below 50 °C. Consequently, a structural enclosure that experiences local heating from power components or sunlight should be evaluated against the higher-stress HDT limit because the part will soften well below the 0.455 MPa value when load concentration is present. Notched Izod impact testing under ASTM D256 produces values in the low 20 J/m range for post-cured material, which is below many unfilled ABS molding grades. Snap-fit arms and latches in SL 7810 therefore require larger root radii and lower insertion deflection than equivalent designs in Accura Xtreme, which sacrifices modulus for much higher ductility.

The values above are representative of X–Y plane specimens after manufacturer-recommended post-cure. Green-state properties are significantly lower, and actual part performance is orientation-dependent. Because cured density is approximately 1.20 g/cm³ compared with unfilled ABS at 1.04–1.06 g/cm³, a part designed for molded ABS will be roughly 13–15 % heavier in SL 7810. This mass increase matters for moving assemblies, handheld devices, and components with inertial loading. Coefficient of linear thermal expansion for SLA photopolymers of this class can be higher than unfilled ABS, but published data for SL 7810 is limited; measurement on final geometry is required before use in precision sliding fits or high-temperature alignment fixtures.

Comparative Grade Selection Hierarchy for SLA Photopolymers

In comparison with other Accura SLA grades, SL 7810 occupies the middle of the stiffness-ductility curve. Accura 25 is a lower-modulus resin with higher elongation and is preferred for snap-fit applications requiring repeated flexure at lower insertion force. Accura 60 reports tensile modulus above 2,900 MPa and is used for high-stiffness transparent prototypes, but its ductility is lower. Accura Xtreme provides the highest impact resistance of the ABS-like group and is selected for extreme snap-fit or impact testing. SL 7810 is differentiated by its opaque white color and a balance of room-temperature tensile stiffness, surface hardness, and moderate heat resistance. It is not the best performer at elevated temperature; Accura Bluestone or similar ceramic-like resins should be considered when HDT and flexural modulus are the primary design limits. Comparison should be made against actual test specimens built in the final orientation because all SLA resins show anisotropic properties.

Application cases for SL 7810 include form-and-fit inspection of ABS-molded electronics housings, master patterns for room-temperature vulcanizing silicone tools, and functional prototypes for low-impact mechanical testing. The white surface improves visibility of highlight lines and dimensional inspection, but it also reveals stair-stepping and support pips more readily than darker resins; polishing therefore requires additional care when the part is used as a cosmetic model. When used as a vacuum-casting master, the part should be conditioned to constant mass and sealed to prevent inhibition of platinum-cure silicones. The material is not recommended for continuous service in hot water above 60 °C, strong alkaline cleaners, or prolonged outdoor UV exposure without painting because the photopolymer network can yellow and embrittle. For functional clips, the notch sensitivity of SL 7810 demands finite-element review of gate radii and part thickness; a design that survives a printed ABS prototype may not survive in SL 7810 if the geometry contains sharp corners.

Regulatory compliance claims for SL 7810 are limited to standard material safety data and application-specific leachable testing required by the customer. It is not sold as an ISO 10993-1 biocompatible grade. No food-contact approval under FDA 21 CFR 177.1520 is implied. For electronics enclosures, UL 94 V-0 is not a typical property of unfilled SLA photopolymers; component-level flammability classification must be tested on the final production geometry. The resin should be handled with nitrile gloves and used with local exhaust ventilation to control acrylate vapor exposure. Waste photopolymer must be disposed according to local regulations and is not suitable for municipal solid waste streams. Storage should be in the original opaque container away from UV and blue-violet light sources, and the shelf life stated by the manufacturer should be tracked as part of lot control.