3D Systems Figure 4™ ELAST-BLK 10 Design Elastomer is a black, UV-curable acrylate photopolymer supplied as a single-component liquid resin for the Figure 4 Digital Light Processing platform. The material is processed at 405 nm using the platform’s UV-LED projection array and is intended for elastomeric components such as housing seals, gaskets, vibration isolators, strain-relief boots, and grip overmolds where molded or extruded elastomers would otherwise delay design verification. In its cured state, the product occupies a Shore A hardness class in the lower elastomer range and exhibits strain recovery and tear resistance that are not available in rigid Figure 4 materials or in standard FDM TPU parts with fused-filament anisotropy. The product is typically printed at a layer thickness of 0.05 mm on Figure 4 Standalone, Modular, or Production systems. Because cure conversion in the green state is incomplete, mechanical properties are achieved only after validated solvent cleaning and UV post-cure. The cured network is black in appearance, which limits optical transmission and may retain heat more readily in infrared-facing service conditions than clear or light-colored resins. Users should regard the published property set as applicable to post-cured test coupons, not to arbitrary part geometries.

What is the measured mechanical envelope after standard ASTM conditioning?

Mechanical property data for Figure 4 ELAST-BLK 10 are conditioned and tested according to plastics and elastomer test methods. The manufacturer’s technical data sheet reports a nominal Shore A hardness of 65 when measured by ASTM D2240-15 on a post-cured plaque. Tensile strength at break is commonly reported in the 4.5–5.5 MPa range when tested per ASTM D638-14 Type IV specimens at 50 mm/min crosshead speed; elongation at break typically exceeds 150%. Tear strength, measured by ASTM D624 Die C, is specified in the low-teens to 20 kN/m range depending on post-cure dose and specimen orientation. Compression set under ASTM D395-18 Method B after 22 h at 70 °C is used as a screening parameter for sealing force retention; the product is formulated for lower compression set than high-elongation flex photopolymers, but published values should be read against the certificate of analysis for the specific lot because pigment dispersion and post-cure irradiance shift network crosslink density. The tensile modulus is lower than that of Figure 4 FLEX-BLK 20, and the material tears before yield; therefore yield-strength specifications used for rigid photopolymers do not apply.

The property envelope is orientation-dependent. Digital light processing builds crosslinked network layers through sequential projection; knitted interfaces between layers can concentrate stress in tensile loading when parts are built with large flat surfaces parallel to the build platform. For critical sealing parts, users should prepare witness coupons in the same orientation as the production part and compare measured elongation at break with the datasheet range. Chemical aging and thermal aging are not captured by the short-term tensile table; swelling, stress relaxation, and compression set must be evaluated separately under service conditions using ASTM D471-16 and ASTM D395-18 as applicable.

In production-scale Figure 4 cells, batch-to-batch viscosity drift and pigment settling are the two most frequent processing faults. The material should be conditioned at 18–28 °C before filling the vat, and the vat should be mixed or recirculated after idle periods longer than 12 h. Build failures caused by insufficient recoat present as horizontal line delamination in the green part, often at the same Z height across multiple cycles. Increasing UV energy to compensate for recoat defects is ineffective and instead raises the risk of overcuring thin features. The correct response is to restore vat temperature and viscosity, check the recoater blade for wear, and confirm that the material has not been diluted with solvent from an insufficiently dried build platform. Because the material is a pigmented photopolymer, settled pigment alters both cure depth and final durometer if not resuspended. Published viscosity data for this specific configuration vary with moisture and temperature; the supplier’s certificate of analysis should be used as the lot reference rather than a single general viscosity value.

Solvent cleaning, post-cure uniformity, and dimensional compensation

After the build plate exits the Figure 4 system, residual liquid resin films attach to downward-facing surfaces. The green part is not dimensionally stable until the liquid resin is removed and the network is further crosslinked. Two-stage cleaning in ≥ 99% isopropyl alcohol or an approved Figure 4 rinse solvent is required; first-stage soak followed by second-stage agitation removes uncured resin from recessed channels. Total solvent residence time should be limited to the manufacturer’s recommended window, typically 3–10 min, because extended immersion swells the network and can produce a measurable increase in part volume. After cleaning, compressed air drying removes solvent from blind pockets. A UV post-cure chamber operating in the 365–405 nm band with controlled irradiance and thermal load is then used. The exact post-cure time depends on mass, wall thickness, and UV chamber model; under-cure produces residual monomer migration, reduced tensile strength, and higher compression set. Over-cure is less commonly observed but can shift color and reduce elongation at break. Operators should validate post-cure uniformity by cutting or testing witness coupons placed in the same chamber load, then measuring durometer or crosslink-related properties against the lot reference.

Dimensional compensation for elastomer parts differs from rigid resins because the cured network shrinks slightly after post-cure and then can expand in humid environments. The part coordinate system should be compensated using the same post-cure process intended for production. Support placement on elastomer parts is also oriented differently from rigid parts; thin elastomer sections may require additional support density to prevent tear during part removal. Points of attachment should be placed at thicker non-functional sections to avoid leaving surface defects. In high-humidity storage above 60% relative humidity, dried parts may absorb water at the surface; dimensional checks should therefore be performed after conditioning at controlled humidity rather than immediately after post-cure.

When sealing and vibration-isolation parts displace molded rubber or TPU

Typical usage territory includes low-to-moderate production sealing parts where compression set, tear strength, and surface resolution determine whether a photopolymer can replace compression-molded EPDM or cast polyurethane. Gasket prototypes built from Figure 4 ELAST-BLK 10 can be evaluated for sealing force by stacking tolerances and measuring compression-deflection curves under a universal testing machine; however published data for this specific configuration is limited. For a housing gasket with a nominal 25% compression, the material’s lower Shore A hardness produces a lower reaction force than FLEX-BLK 20 at the same compression; this is useful where sheet-metal enclosures have limited screw torque. Vibration isolation pads and strain-relief boots benefit from elastomeric damping, but dynamic mechanical analysis of the material at operating frequency should be performed before replacing a formulated diene rubber. The material is not intended for continuous dynamic flex fatigue in rotating tires or high-frequency bellows except where end-use validation demonstrates adequate crack growth resistance. Abrasion and cut-growth resistance are lower than high-tear production elastomers; parts exposed to sharp metal edges should include radiused geometry.

The product differs from Figure 4 RUBBER-65A BLK in its intended use as a design elastomer. Both can exhibit Shore A values in the same range, but the production elastomer is supplied with a different formulation package and should be considered when long-term compression set, tear strength, and repeatable production lot data are critical. Figure 4 FLEX-BLK 20 is a higher-modulus flexible photopolymer with less elongation and is selected for snap-fit closures and durable enclosures rather than seals or vibration isolators. Rigid materials such as Figure 4 PRO-BLK 10 and Figure 4 TOUGH GRY 10 are not interchangeable: their yield and impact behavior are governed by different ASTM methods, and they do not provide the recovery required for gasket seating.

Chemical compatibility should be validated before service. The cured network generally resists water and common household cleaners, but prolonged contact with strong ketones, esters, aromatic hydrocarbons, and chlorinated solvents may soften, swell, or extract low-molecular-weight species. Swelling follows the general solubility-parameter behavior of acrylate networks; users should screen using ASTM D471-16 reference fuels or oils when sealing applications involve automotive fluids. The material is black and opaque; optical transmission testing per ASTM D1003 is not applicable. Continuous exposure to elevated temperature above 60 °C can accelerate stress relaxation and oxidation at part surfaces, particularly at fill lines or knit lines created by the digital-projection pattern. Surface tack after cleaning is usually a sign of insufficient post-cure or inadequate solvent removal; operator corrective action is to extend post-cure in a calibrated chamber rather than to apply additional topcoat. Regulatory compliance is application-specific: no statement of food-contact, medical, or RoHS compliance should be inferred from the product name. The supplier’s safety data sheet and certificate of analysis should be consulted for lot-specific REACH SVHC declarations and disposal requirements, and the cured resin should not be considered a food-contact or implantable material unless a specific regulatory certification, such as FDA 21 CFR 175.300 or USP <261>, is provided for the intended application.