| HS Code | 940979 |
| Color | Black |
| Liquid Density | 1.10 g/cm³ at 25°C |
| Solid Density | 1.15 g/cm³ at 25°C |
| Viscosity | 400 cP at 30°C |
| Critical Exposure | 8.5 mJ/cm² |
| Penetration Depth | 0.12 mm |
| Tensile Strength | 48 MPa |
| Tensile Modulus | 2650 MPa |
| Elongation At Break | 9% |
| Flexural Strength | 76 MPa |
| Flexural Modulus | 2380 MPa |
| Izod Impact Notched | 40 J/m |
| Hardness | 80 Shore D |
| Glass Transition Temperature | 82°C |
| Heat Deflection Temperature At 0 45 Mpa | 63°C |
| Heat Deflection Temperature At 1 82 Mpa | 54°C |
| Water Absorption | 0.35% |
| Dielectric Constant At 1 Mhz | 3.5 |
| Dielectric Strength | 16 kV/mm |
| Volume Resistivity | 1.0E15 ohm-cm |
| Coefficient Of Thermal Expansion | 90 µm/m/°C |
As an accredited 3D Systems Accura ABS Black (SL 7820) Plastic for SLA Systems factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in a 1 kg opaque plastic bottle with cap, labeled 3D Systems Accura ABS Black (SL 7820) SLA resin. |
| Container Loading (20′ FCL) | Container loading (20′ FCL): palletized 3D Systems Accura ABS Black (SL 7820) resin, securely strapped, climate-protected, labeled, and safely transported. |
| Shipping | 3D Systems Accura ABS Black (SL 7820) is not regulated as dangerous goods for transport by DOT, IMDG, IATA/ICAO, or ADR/RID. Ship in tightly sealed original containers, away from heat, light, and ignition sources, following applicable regulations. Always include the SDS and emergency contact information. |
| Storage | Store 3D Systems Accura ABS Black (SL 7820) resin in original, tightly closed containers in a cool, dry, well-ventilated area away from direct sunlight, heat, ignition sources, and strong oxidizers. Keep away from UV light. Maintain recommended temperature, typically 18–25°C; avoid freezing or excessive heat. Protect from damage; use secondary containment if required. Follow SDS and local regulations. |
| Shelf Life | Shelf life is 12 months when stored unopened in the original container at 18–28°C, away from light and moisture. |
In automotive interior prototype programs where production components are later converted to injection-molded acrylonitrile-butadiene-styrene, Accura ABS Black SL 7820 is processed on 355 nm laser-based stereolithography platforms as a fully formulated, single-component photopolymer. The vat is charged at a 100:0 as-supplied resin to external solvent or reactive diluent ratio; no formulation adjustment is authorized. Cold-conditioning correction is performed by holding the vat at 28–30°C and recirculating gently through a 50 µm filter instead of altering the photopolymer chemistry. Compliance for prototype use is limited to material-level REACH (EC 1907/2006) and RoHS (2011/65/EU) declarations, while conventional production homologation under IATF 16949 is not transferred to this thermoset because it is a prototype and tooling photopolymer. Tensile benchmark checks are executed on specimens built in the same orientation and post-cure schedule as the vehicle part, with testing per ASTM D638-14 or ISO 527-2:2012; heat deflection is checked via ASTM D648-18 at 0.45 MPa. The black pigment reduces photon penetration relative to clear or translucent SLA resins, so on systems with a blade recoater the sweep speed is reduced for large cross-sections to avoid thin-layer delamination at overhung return edges. Typical downstream processing for interior black trim validation includes building at 0.1 mm layer thickness with drain holes on closed volumes, support removal with flush-cut pliers, a two-stage rinse in ≥99% isopropanol or tripropylene glycol monomethyl ether under 40 kHz ultrasonic agitation, forced-air drying at 40°C, and UV post-cure in a 365 nm chamber until the surface passes a tack-free wipe test. Terminal part types produced under this route include HVAC vent bezels, instrument cluster hoods, steering wheel switch blanks, and door pull cup inserts for early fit-and-feel reviews. Operational boundary: continuous exposure at the upper end of automotive cabin air temperatures can reduce stiffness below datasheet room-temperature values; parts in upper dash or near-defroster locations require thermal soak verification before permanent use because the HDT measured under ASTM D648-18 at 0.45 MPa is lower than the 80–105°C upper-dash air outlet temperatures commonly seen in parked vehicles.
In handheld electronics validation, cantilever snap arms and annular latching features produced from SL 7820 are evaluated for insertion force reproducibility and repeated engagement before aluminum tooling is released. The resin bath remains a 100:0 SL 7820 to internal mold release, flexibilizer, or solvent ratio; rinse agents are outside the formulation and controlled at 90–100% isopropanol or TPM concentration to avoid surface plasticization. Compliance for this enclosure work is anchored to product-level safety review under IEC 62368-1:2018 and electrostatic control under IEC 61340-5-1:2016; flammability classification is not assumed to be UL 94 V-0, and any live-circuit or battery enclosure must be independently tested at the final thickness and post-cure state. Material tensile elongation is obtained from the datasheet according to ASTM D638-14, and allowable snap-fit strain is calculated as 0.5× the reported elongation at break for cyclic engagement above 20 cycles to account for interlayer adhesion variation and sharp corner stress concentration. The printing process for snap features orients cantilever arms off-axis by 10–15° from the build plane so that the neutral bending axis does not align with the weakest resin-rich interlayer boundary; support contact tips are confined to non-mating surfaces and removed before cure. Post-processing uses 0.1 mm layer compensation, a two-step alcohol rinse, and UV post-cure at 365 nm for 30–60 min depending on arm thickness; laser micrometer checks confirm feature dimensions before assembly. Terminal product types include battery door latches for portable scanners, SIM card tray extraction prototypes, over-center clamps on handheld testers, and removable battery cover snap features. Operational boundary: published data for this specific snap-fit cycle count is limited; therefore designs that require more than 100 insertion cycles or high service temperatures should not be qualified solely on room-temperature tensile data gathered under ASTM D638-14.
Before a polyurethane vacuum-casting run is committed from stereolithography masters, the interaction between residual unpolymerized acrylate on SL 7820 and the selected RTV silicone chemistry is the dominant process risk. The master pattern is used as a 100% solid SL 7820 shape; the resin is not dissolved or mixed into the mold rubber. Condensation-cure RTV systems are catalyzed at the tin supplier’s ratio, commonly 5–10 wt% catalyst relative to base, while platinum-cure addition systems are mixed at the manufacturer’s specified 10:1 A:B ratio by weight; in both cases a seal coat is applied to the post-cured SL 7820 pattern surface at 25–50 µm dry film thickness to block migration of any unreacted species. Industry compliance for the master pattern itself is limited to material declarations under REACH (EC 1907/2006) and RoHS (2011/65/EU); the RTV and polyurethane casting materials carry their own food-contact or medical-grade documentation, and FDA 21 CFR 177.2600 is checked only if the final molded article contacts aqueous or fatty foods. The downstream process involves building the master with 0.1 mm layer thickness and 0.5–1.0 mm sacrificial sanding stock on cosmetic A-surfaces, post-curing under 365 nm UV until tack-free, dry-sanding from 320 to 800 grit followed by a polyester glazing putty at a 2:1 putty-to-hardener volume mix, sealing, and constructing a two-part silicone mold in a vacuum degassing chamber at −0.09 MPa or better. After mold cure, polyurethane replicas are cast under vacuum, cured in a 40–60°C convection oven, and deflashed. Terminal part types include dashboard control knobs, cable grommets, soft-touch hand grips, and instrument bezels in 55–70 Shore D polyurethane. Operational boundary: platinum-cure silicone is more sensitive to residual acrylate than tin-cure silicone; lack of a seal coat or under-cure can inhibit surface catalyst and leave a tacky mold face, a known failure mode in rapid tooling workflows.
For limited-run interior trim pieces situated near glazing, the use of SL 7820 is constrained by the fact that the datasheet does not classify the material as a UV-stable exterior grade; therefore black surface appearance and dimensional control are maintained only after an opaque primer and topcoat system is added. The resin-to-coating stack is configured as a 100% SL 7820 substrate with no flexibilizer or impact modifier added to the photopolymer; a two-part adhesion promoter is applied at the paint vendor’s specified reduction, typically 1:1 by volume with a high-gravity solvent for ABS substrates, followed by a 2:1 two-pack polyurethane topcoat by volume. Compliance testing follows SAE J2412:2004 for accelerated interior weathering, ASTM G154-16 for UV-condensation screening, and ISO 2409:2020 for cross-cut adhesion; the unpainted photopolymer is not submitted directly to these tests because black SLA surfaces can whiten under alcohol or alkaline cleaner contact. The downstream process includes building at 0.1 mm layer thickness with A-surface orientation toward the recoater blade plane, support removal, isopropanol rinse in a two-stage bath, forced-air drying at 40°C, UV post-cure at 365 nm, solvent wipe with naphtha, application of a polyester glazing putty to level layer lines at a 2:1 putty-hardener volume ratio, dry sanding from 400 to 800 grit, sealing, and a 2K polyurethane black satin topcoat. Terminal part types include A-pillar garnish prototype runs of 10–50 units, belt-line finisher trials, and shift knob collars that must match production black interior color chips. Operational boundary: these parts are not qualified for direct exterior body application, and any location receiving focused sunlight through side glass must be painted with an opaque, UV-blocking topcoat; unpigmented or clear-coated SL 7820 is not recommended without long-term color shift testing.
Only on SMT assembly lines with active ESD controls is SL 7820 substituted for CNC-machined acetal and glass-filled laminate fixtures, because the unfilled thermoset is electrically insulative and cannot by itself meet dissipative or conductive ESD flooring requirements. The fixture substrate is 100% SL 7820 as printed; no carbon or antistatic filler is compounded into the resin. Where static-dissipative behavior is required, a two-part epoxy surface coat is applied at the manufacturer’s specified 2:1 resin-to-hardener weight ratio with a target dry film thickness of 25–75 µm and tested per IEC 61340-5-1:2016 and ANSI/ESD S20.20-2014; the surface resistance of the uncoated SL 7820 substrate is expected to exceed 1012 Ω under ASTM D257, so grounding is achieved through inserted brass threads and field-installed ground leads rather than through the printed plastic itself. The downstream process includes building the fixture blank at 0.1 mm layer thickness, reaming holes to consistent size with a carbide reamer at 1,000–2,000 rpm, heat-setting brass inserts at a probe temperature near 180°C, and then coating or sealing the printed surface to reduce particulate shedding and chemical absorption.
| Qualification item | Standard/method | Observed or required range |
|---|---|---|
| Uncoated SL 7820 surface resistance | ASTM D257 | >1012 Ω (insulative) |
| Static-dissipative coating dry film thickness | ANSI/ESD S20.20-2014 / IEC 61340-5-1:2016 | 25–75 µm |
| Dissipative coating resistance after cure | IEC 61340-5-1:2016 | 106 to <109 Ω |
Terminal part types include stencil alignment pallets, selective soldering masks, board support pins with vacuum channels, and robotic gripper nests for odd-form component placement. Operational boundary: when the assembly line requires a surface resistance below 109 Ω per ANSI/ESD S20.20-2014, SL 7820 alone will not qualify unless an external dissipative coating is maintained and verified at defined intervals.
For laboratory diagnostic instrument chassis prototypes that undergo daily wipe-down with disinfectant or alcohol-based cleaners, the visual durability of black SL 7820 surfaces is an acceptance criterion that cannot be inferred from bulk mechanical data alone. The enclosure is printed as a 100% monolithic SL 7820 shell with no added elastomer phase; where a cleanability test is required, cleaning agents are prepared at 70:30 isopropanol to deionized water by volume for routine wipe-down, while stronger solvents are excluded because they can stress-crack thin wall sections or dull the surface. Compliance for non-patient-contact laboratory equipment housings is generally limited to the low-voltage safety requirements of IEC 61010-1:2010/AMD1:2016, RoHS (2011/65/EU), and REACH (EC 1907/2006); the photopolymer is not certified to ISO 10993-1 and must remain behind secondary barriers if the instrument produces clinically relevant sample contact. The production route for these enclosures includes 0.1 mm layer thickness building with drain holes at the lowest edge of internal cavities, isopropanol rinse, forced-air drying, UV post-cure at 365 nm, and manual sanding of visible edges to remove support witness marks. Terminal part types include handheld analyzer housings, benchtop diagnostic reader bezels, and internal card guides that position printed circuit assemblies. Operational boundary: black SL 7820 can show scratch whitening under point-load abrasion or after prolonged contact with more than 70% alcohol; a post-cure plus matte clear seal is used where the surface will be handled by operators, but gloss and color drift must be re-qualified after coating because the datasheet values apply only to the as-cured resin.
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3D Systems Accura ABS Black (SL 7820) is a black, acrylate-based photopolymer formulated for vat photopolymerization on 3D Systems stereolithography platforms equipped with a 355 nm solid-state laser. The material is classified as an ABS-like engineering resin because its post-cured tensile, flexural, and impact response is designed to approximate injection-molded ABS for form, fit, and limited functional testing. The liquid photopolymer is opaque and black, which permits visual inspection of surface finish without the post-paint step required for translucent SLA grades. Mechanical characterization is performed on post-cured specimens conditioned at 23 ± 2 °C and 50 ± 5 % relative humidity in accordance with ASTM D618-21. The following table records typical post-cured values published by the supplier; batch-specific material certifications should be consulted for production acceptance criteria.
| Property | Test method | Published value |
|---|---|---|
| Cured density | ASTM D792-20 | 1.16 g/cm³ |
| Tensile strength | ASTM D638-14 | 45 MPa |
| Tensile modulus | ASTM D638-14 | 2,500 MPa |
| Elongation at break | ASTM D638-14 | 6 % |
| Flexural strength | ASTM D790-17 | 68 MPa |
| Flexural modulus | ASTM D790-17 | 2,300 MPa |
| Notched Izod impact | ASTM D256-10 | 44 J/m |
| Heat deflection temperature at 0.46 MPa | ASTM D648-18 | 51 °C |
| Heat deflection temperature at 1.82 MPa | ASTM D648-18 | 47 °C |
| Hardness, Shore D | ASTM D2240-15 | 85 |
The heat deflection temperature values under 0.46 MPa and 1.82 MPa loads indicate that SL 7820 is not a high-temperature stereolithography grade. Continuous service above 45 °C under mechanical load should be evaluated with creep testing; the published datasheet does not provide long-term creep data. The notched Izod impact value of 44 J/m obtained under ASTM D256-10 should not be used as a substitute for high-speed puncture or drop-impact data; instrumented puncture testing should follow ASTM D3763-18. The tensile values shown are typically generated in the XY build orientation; the supplier datasheet does not report Z-axis tensile strength, and anisotropic behavior across layer interfaces must be characterized for load-bearing designs.
Accura ABS Black (SL 7820) differs from Accura 25 and Accura 60 primarily in pigmentation, elongation at break, and heat deflection response. Accura 25 is a polypropylene-like photopolymer engineered for higher elongation and lower flexural modulus; it is selected for living-hinge prototypes and snap-fit parts that must survive repeated bending. Accura 60 is a clear polycarbonate-like grade with higher optical clarity, higher tensile strength, and higher heat deflection temperature than SL 7820; it is specified when translucency or stiffer high-temperature response is required. By contrast, SL 7820 provides an opaque black surface and moderate impact resistance, with a published elongation at break of 6 %, a tensile strength of 45 MPa, and a Shore D hardness of 85. The black pigment is not spectrally inert; it absorbs laser energy and can reduce the optical penetration depth relative to unpigmented or lightly pigmented SLA resins. Build style, layer thickness, and laser exposure settings therefore cannot be transferred directly from Accura 25 or Accura 60 to SL 7820 without validating the working curve and recoating parameters on the target SLA platform.
Cross-contamination management on shared production machines is another differentiating factor. Residual flexible resin in the vat or recoating assembly can reduce the effective modulus of SL 7820 in local zones; production lines typically designate separate build trays, squeegees, and wipers for black ABS-like material, especially when switching from Accura 25 or Accura 60. Viscosity should be monitored with a rotational viscometer according to ISO 3219:1994 because recoating defects in SL 7820 can appear as surface waviness or layer-thickness variation when viscosity shifts outside the supplier range.
The SL 7820 designation identifies a specific formulation with black pigmentation and an ABS-like property profile. The liquid resin is processed through a vat photopolymerization sequence in which a recoating blade spreads a film of resin, a 355 nm laser selectively irradiates the layer, and the build platform indexes by the selected layer thickness. The build processor uses working curve parameters to assign cure depth and layer-to-layer adhesion exposure, and the exact values may vary by SLA platform generation and recoat speed. Build chamber temperature should be maintained within the machine manufacturer’s range; excessive cooling raises resin viscosity and creates recoating defects, while excessive heating can age the liquid resin and shift laser absorption.
Because black pigmentation absorbs more light than translucent resins, the optical penetration depth is lower. Working curve data for SL 7820 therefore produces different process exposure requirements than unpigmented materials in the same machine. Operators should import the current Accura ABS Black material package into 3D Sprint or the legacy build processor rather than creating manual exposure offsets from other resins. Build style choices, such as the number of burn-in layers, layer thickness, and hatch spacing, influence green-part accuracy and post-cure shrinkage. Production builds should begin with a small validation run to establish build offset factors for critical dimensions and internal channel diameters; offset data should be recalculated after any change in layer thickness, post-cure oven, or platform model.
Green-state handling procedures have a measurable effect on final dimensions and surface condition. The polymerized network retains unreacted acrylate species after the build, and solvent cleaning in isopropyl alcohol or a TPM-based solution removes residual liquid resin from recesses, blind holes, and internal channels. Ultrasonic cleaning is permissible for short cycles, but thin walls below 1.0 mm can suffer cavitation erosion; the use of ultrasonic equipment with frequency sweeps should be validated on test coupons before cleaning production parts. Support removal is preferably performed before post-cure, because post-cured supports become more brittle and their fracture can leave surface craters that penetrate into functional walls. Post-cure is carried out in a UV chamber with UVA output; uniform irradiance should be verified with a calibrated radiometer, and the chamber load should be rotated or rearranged to avoid shadowing. Under-curing of thick sections leaves reduced crosslink density, lower heat deflection temperature, and residual monomer that can inhibit paint adhesion or silicone cure. Over-curing can embrittle thin walls, shift the black surface toward brown or grey, and reduce the feasibility of tapping or screw-boss rework.
Internal channels should include drain holes at the lowest point of the uncured liquid path; residual resin trapped in blind cavities cannot be fully removed by passive soaking and can produce dimensional drift or surface tack after post-cure. For channels narrower than 2 mm, flushing with a low-pressure solvent pump is preferred over immersion because capillary retention of pigmented resin is higher than in many unpigmented resins. Post-cure systems should provide UVA irradiance in the supplier-recommended range; parts should be suspended or placed on open mesh trays to minimize shadowing. If part temperature during post-cure exceeds the heat deflection temperature, internal stresses can relax and distort unsupported overhangs, particularly in long flat sections and thin ribs. Fixturing or sacrificial support may be required to preserve flatness during post-cure.
The mechanical boundary conditions for SL 7820 are defined by the glass transition region of the crosslinked acrylate network and by the layerwise construction method. The heat deflection temperature values of 51 °C at 0.46 MPa and 47 °C at 1.82 MPa mean that parts should not be specified for continuous load-bearing service above 45 °C unless the design has been tested for creep under the expected load. Dimensional measurements should be made only after the part has stabilized for 24 h at 23 ± 2 °C; measuring solvent-swollen or partially cooled parts produces non-representative results. For assembly features such as tapped holes, thread-forming screws, and press-fit inserts, the low Z-axis interlaminar strength of stereolithography parts requires orientation-specific validation. If a boss is built with its axis parallel to the Z direction, the threads are formed across layer interfaces and may fail at lower torque than the same geometry built in the XY plane. The supplier datasheet does not provide Z-axis tensile or shear values; manufacturers should generate orientation-specific test data using the same platform, layer thickness, and post-cure cycle intended for production.
Chemical compatibility testing is advisable before SL 7820 parts are exposed to automotive or industrial fluids. Acrylate photopolymers are not generally resistant to ketone solvents; exposure to acetone or methyl ethyl ketone can cause swelling, surface cracking, and loss of dimensional accuracy. This behavior is not identical to thermoplastic ABS, although both materials can be attacked by ketones. Immersion testing should be conducted according to ISO 175:2010 for the specific fluid and temperature range. The material is also not a candidate for continuous outdoor ultraviolet exposure; the acrylate network can undergo surface oxidation and post-cure embrittlement, even though the black pigmentation may delay visible yellowing relative to unpigmented SLA resins. Testing of weathering resistance should follow ISO 4892-2:2013 or ASTM G154-16.
Dimensional tolerance after post-cure should be derived from production history rather than assumed from injection-molded ABS shrinkage values. If the supplier does not publish build offset data for the selected platform generation, a three-axis build offset study should be performed. A coordinate measuring machine calibrated to ISO 10360-2:2009 is suitable for measuring critical features. Surface flatness should be checked after masking and block sanding; thin walls may warp during post-cure if unsupported. Threaded features should be gauged after post-cure, because minor thread class can shift with shrinkage and may require chasing or tapping.
The product is deployed in black functional prototype housings, automotive interior trim samples, and consumer electronics enclosures where opaque black appearance, moderate impact resistance, and the ability to paint or finish surfaces are required. Snap-fit designs should be evaluated with the published elongation at break of 6 % and notched Izod value of 44 J/m; clip features built parallel to the XY plane generally retain higher bending resistance than those crossing layer interfaces. The material is also used as a master pattern for room-temperature vulcanizing silicone tools. Platinum-cure silicone systems can exhibit cure inhibition at contact surfaces if the acrylate network is not fully post-cured or if residual monomer remains; the use of barrier coatings or tin-catalyzed RTV systems is a common production countermeasure. Surface gloss after sanding and priming can be measured with a 60° glossmeter according to ASTM D523-14 to verify finish consistency across a batch of prototype parts.
For painted enclosures, adhesion testing should follow ASTM D3359-17 after application of the selected primer or two-component polyurethane coating. The base SL 7820 material is not formulated as an electrostatic dissipative photopolymer; if surface resistivity control is required, a conductive coating or post-treatment is necessary and surface resistivity should be measured according to ASTM D257-14. Surface roughness of visible surfaces can be quantified using profile parameters specified in ISO 4287:1997, particularly after support removal and sanding operations.
When SL 7820 replaces machined ABS, the design benefits from direct construction of internal channels and undercuts, but the material loses the isotropic mechanical response of extruded or cast ABS stock. Layer interfaces introduce a preferred failure plane, particularly in Z-axis tensile loading. Threaded boss performance is a specific area of divergence: machined ABS can often accept thread-forming screws without inserts, whereas SL 7820 bosses may strip at lower thread engagement lengths. The use of heat-set threaded inserts or through-bolts with washers is preferred; fastener pull-out testing should use a calibrated torque wrench and record torque-to-strip values against a defined insert material and boss outer diameter. Tensile property references should follow ISO 527-1:2019 or ASTM D638-14, but joint strength is not equivalent to parent material tensile strength.
When SL 7820 replaces molded ABS, mold flow orientation and weld lines are replaced by build orientation and layer boundary effects. Molded ABS parts typically display a smooth surface with controlled gloss and known shrinkage; SL 7820 requires support removal and sanding, and its linear shrinkage during post-cure can vary with part thickness. Build offset values should be derived from per-axis measurements on a coordinate measuring machine calibrated to ISO 10360-2:2009 and adjusted for the chosen layer thickness. The material is suitable for visual and limited functional prototypes, but it is not a direct drop-in replacement for injection-molded ABS in all load cases; published data for high-cycle fatigue of SL 7820 is limited, and fatigue-sensitive designs should be tested under the intended load spectrum.
Master patterns for RTV molding require complete post-cure, solvent-free surfaces, and often a seal coat, because residual monomer can inhibit platinum-catalyzed silicone cure. Dowel pins and locating features molded into the pattern should be oversized according to the measured post-cure shrinkage of the specific platform and layer thickness. Silicone mold release agents should be selected for compatibility with both the cured photopolymer and the elastomer; if release performance is marginal, a primer sealer can provide a barrier film.
