Product model Accura 60 Plastic is an unfilled liquid photopolymer resin supplied by 3D Systems for vat photopolymerization on stereolithography (SLA) systems equipped with a 355 nm solid-state laser. The material is part of the Accura family and is identified in supplier literature as a rigid, amber-translucent resin with a polycarbonate-like balance of hardness, stiffness, and impact resistance. Unlike filled grades or castable materials, Accura 60 is not formulated for direct shell investment casting or high-temperature service. The post-cured mechanical values are listed in the table. These values are manufacturer-published typical results from post-cured specimens; they are not design allowables and must be verified against the certificate of analysis for each lot.

The cured network is a thermoset and cannot be melt-reprocessed, heat-staked, or solvent-welded in the same manner as a thermoplastic. The material is therefore specified for rigid functional prototypes, translucent housings, inspection fixtures, and master patterns, but it is not a direct replacement for machined polycarbonate or ABS. Because the material is amber-translucent rather than water-clear, optical transmission must be validated when visible light transmission is a requirement.

What Differentiates Accura 60 from Flexible, High-Impact, and Optically Clear Resins?

Within the Accura family, Accura 25 is supplier-classified as polypropylene-like and provides higher elongation with lower flexural modulus. Accura 55 is supplier-classified as ABS-like and provides a tougher balance of impact and rigidity. Accura Xtreme shifts the balance further toward high impact, while Accura ClearVue is optimized for water-white clarity rather than load-bearing hardness. Accura 60 differs from these grades by returning a hardness of Shore D 86, a tensile modulus near 3,000 MPa, and a flexural modulus near 2,700 MPa, with elongation at break limited to approximately 5 %. This combination places Accura 60 in the rigid glassy segment of the SLA materials portfolio. For components requiring repeated snap-fit deflection or notched impact resistance, Accura 55 or Accura Xtreme should be considered. For optical transparency, Accura ClearVue or WaterClear Ultra should be evaluated. For continuous service above 54 °C under load, high-temperature grades such as Accura 48HTR or Accura Bluestone are more appropriate.

Production-scale behaviour of Accura 60 is influenced by build orientation and post-cure history. Coupons printed with the tensile axis in the XY plane typically approach the published datasheet values; coupons built with the tensile axis aligned to the Z direction may show lower elongation because interlayer conversion is not identical to in-plane crosslinking. The manufacturer does not publish a complete anisotropic mechanical data set for Accura 60, so orientation-specific characterisation is required for structurally loaded parts. Large solid cross-sections may retain residual stress after build; heating during post-cure before the green-state surface is supported can induce warpage. On machines with a vacuum-assisted recoater, resin viscosity and surface tension affect recoat time. The 3D Systems material profile adjusts blade speed, laser exposure, hatch spacing, and z-wait to maintain layer time. Deviating from the profile to reduce build time can produce under-cured surfaces, delamination, and lower tensile strength. The nominal layer thickness in common builds is 0.100 mm; finer layers improve sidewall finish at the cost of longer build time but do not alter the chemistry. Post-curing protocols specified by the equipment manufacturer should be followed; published data for specific UV chamber configurations is limited, so part-specific validation is required.

Thermal Boundaries and Modulus Retention Near the Glass Transition

The heat deflection temperature for Accura 60 is 54 °C at 0.46 MPa and 51 °C at 1.82 MPa when tested under ASTM D648. The narrow gap between these two values indicates that the thermoset network loses load-bearing capacity over a short temperature interval. Load-bearing features exposed to under-hood temperatures, hot washdown cycles, or heated tooling above 45 °C may creep, undergo stress relaxation, or show dimensional relaxation. In assemblies with interference-fit metal inserts, the retained strain energy can exceed the high-temperature creep resistance of the polymer and produce stress whitening or cracking. Accura 60 is not a high-temperature SLA resin. The material should not be used for parts that must sustain mechanical load above 50 °C without thermal validation. The low elongation at break also means that repeated thermal cycling can generate internal stress in thick cross-sections. A normalisation annealing step is sometimes used, but published data for annealing protocols on production-scale SLA systems is limited, and the user must validate the exact thermal cycle.

When Accura 60 Is Used as a Master Pattern for RTV Silicone Tooling

Accura 60 is frequently processed into master patterns for room-temperature-vulcanisation silicone tooling because the cured surface can be sanded, filled, primed, and polished. The hardness of Shore D 86 supports fine details such as ribs, bosses, and snap-fit retainers during tool construction. A potential processing constraint is the inhibition of platinum-cure silicones by some acrylic or epoxy-based photopolymers; a barrier coat or a small-scale cure compatibility test is required before tool construction. The pattern should be conditioned at 23 ± 2 °C prior to final inspection because moisture uptake can alter dimensions by a few tenths of a percent. For RTV tools that will be cured or used above 50 °C, Accura 60 is not recommended because pattern distortion can occur during silicone cure or subsequent resin casting.

Solvent Resistance Depends on Crosslink Density and Exposure Duration

The cured polymer resists water, many dilute acids, and aliphatic hydrocarbons but is softened by ketones, esters, chlorinated solvents, and strongly alkaline solutions. The manufacturer’s datasheet does not provide a full chemical compatibility matrix; users must test the specific solvent, process fluid, or lubricant in service conditions. Dimensional change is governed primarily by water absorption and internal stress relaxation. Parts stored in humid conditions should be conditioned in accordance with ASTM D618 or ISO 291:2008 before metrology or mechanical testing. Reporting should include conditioning environment, test standard, batch identifier, and build orientation. Coordinate measuring machine data collected on green-state parts before post-cure is not representative of final dimensions because post-cure shrinkage is not negligible. For quality control, the user should establish a post-cure dimensional baseline for each machine and build layout.

Mechanical testing of Accura 60 is governed by specimen conditioning and test geometry. Tensile bars should be printed, washed, post-cured, and then conditioned at 23 ± 2 °C and 50 ± 5 % relative humidity for a minimum of 40 h in accordance with ASTM D618. Izod impact specimens must be machined to the correct notch radius; printed notches are not equivalent because surface finish and residual stress differ. Flexural testing under ASTM D790 uses three-point loading, and specimen orientation must be reported. Hardness is measured with a durometer on a flat, polished surface. The supplier’s certificate of analysis for the liquid resin is not a substitute for solid-state mechanical testing on the user’s SLA system. An internal acceptance interval should be established from data collected over at least 3 builds on the same platform with the same post-cure chamber. Where the part is used for structural validation, notched Izod impact testing is insufficient; full functional testing under the intended load, temperature, and impact event is required.

Part geometry affects Accura 60 more than material selection because the resin’s low elongation at break concentrates stress at sharp notches. In load-bearing enclosures, internal corners should be radiused to at least 0.5 mm and ribs should be oriented parallel to the principal stress direction. Thin walls below 1.0 mm may warp during post-cure unless supported; wall thickness in the build should follow 3D Systems design recommendations. The material can be machined, tapped, and bonded after cure, but drilling should use low-speed tooling and flood cooling to avoid heat-induced cracking. Bonded assemblies require adhesive selection compatible with the cured photopolymer and the service solvent. Mechanical fastening with self-tapping screws should be validated because the low elongation at break reduces resistance to stress cracking around the boss. A thread-forming screw with reduced flank engagement is preferred over a thread-cutting screw.

For translucent fluid-flow manifolds and visibility blocks, Accura 60 can be polished to a semi-transparent finish. The amber tint becomes more pronounced with thickness, and visible-spectrum transmittance is not specified by the manufacturer under a standardised optical test method. Internal printed channels contain layer lines unless the part is post-machined or coated. These layer lines can trap process fluids, affect pressure drop, and complicate cleaning. For moderate-pressure liquid circulation, the part should be hydrostatically tested because low elongation at break limits burst before leak behaviour. Published data for burst pressure of Accura 60 manifolds is limited; validation must be part-specific. Solvent-based cleaning agents that attack the resin should not be used in service or during maintenance. For fluid-flow visualisation, the surface wetting behaviour and optical contrast with the actual process fluid should be validated before design freeze.

Uncured Accura 60 resin is light-sensitive and should be stored in sealed containers away from ambient light. Prolonged exposure can result in viscosity increase and partial polymerisation. The manufacturer’s safety data sheet and storage instructions should be consulted for minimum and maximum storage temperatures. Resin should not be returned from the machine vat to the original bottle because contaminants can accelerate gelation and alter the material profile. Vat cleanliness affects part quality; partially cured resin can deposit on the recoater blade and cause streaking, layer defects, or vat film damage. PDMS-coated vat films and wiper blades should be replaced according to the machine maintenance schedule. Unused resin left in an open vat between builds should be covered and recirculated when the platform supports that capability. The liquid material is not a thermoplastic and should not be disposed of through solvent recycling streams unless permitted by the safety data sheet.