3D Systems VisiJet RCL-EBK-A70 Multi-Material Composites is a two-cartridge material set composed of VisiJet CR-CL 200**, a clear rigid phase, and VisiJet CE-BK, a black elastomeric phase with a nominal Shore A 70 durometer. The A70 suffix in the trade designation corresponds to the elastomer-phase hardness rather than a uniform hardness across the entire printed part. The material set is designed for the compatible ProJet MJP 2500 Plus platform with a build envelope of 294 mm × 211 mm × 144 mm, native resolution of 800 × 900 × 790 DPI, and a layer thickness of 32 µm. The product is not a blended resin; it requires separate material channels for the rigid clear and black elastomer cartridges, plus the M2 SUW support material. The resulting printed parts contain discrete rigid transparent domains and black elastomer domains in a single build, allowing designs to combine structural retainers, transparent windows, and compressible sealing features without tooling or manual assembly.

What separates the CR-CL 200 / CE-BK pair from a single-durometer elastomer?

A single-durometer elastomer produces one stiffness region unless secondary overmolding or assembly is added. The VisiJet CR-CL 200** / VisiJet CE-BK set creates two discrete stiffness domains inside one print. The CE-BK phase is evaluated as a Shore A 70 elastomer according to ASTM D2240-15e1, while the CR-CL 200** phase is characterized by rigid-plastic tensile methods such as ASTM D638-14 or ISO 527-1/-2:2012. This is not equivalent to a continuously graded digital elastomer system; RCL-EBK-A70 does not claim an infinite range of intermediate hardness values across the build. Designers assign the two materials by region in the CAD model, and the printer places each material at the corresponding location. The interface between the phases is a discrete boundary rather than a dissolved transition zone. For a uniform elastomer with no rigid clear features, single-material CE-BK or another homogeneous elastomer is more appropriate. For a transparent rigid part with no soft black features, CR-CL 200** alone is more appropriate. The multi-material set is selected only when rigid clear architecture and black elastomeric function must be integrated without adhesive bonding or mechanical fastening.

In low-volume gasket and seal prototype production, the material set is assigned so that a clear rigid retainer ring is printed in CR-CL 200** and a black sealing lip is printed in CE-BK. The MJP process produces the two regions without adhesive, but the interface is a stress riser and should include a physical interlock or sufficiently large contact area. Compression-set testing on CE-BK-rich plaques should use ASTM D395-18 at the expected service temperature and time, typically 22 h at 23 ± 2 °C or 70 °C depending on the use case. Cast polyurethane compression-set values should not be transferred directly to this material set; published data for RCL-EBK-A70 in a completed gasket geometry is limited. The practical advantage is the elimination of the compression mold, but the printed material is not automatically a direct substitute for high-tear polyurethane in dynamic sealing service.

Hardness, tear resistance, and stress concentration at the A70 boundary

The mechanical behavior of the composite is controlled by the Shore A 70 response of the CE-BK phase and the high modulus of the CR-CL 200** phase. Because the modulus ratio between the clear rigid phase and the elastomer phase is typically greater than 100:1, tensile loading in the elastomer creates strain incompatibility at the interface. In a homogeneous thermoset elastomer, the gauge-section strain field under tensile loading is uniform; in the two-domain composite, the same grip displacement concentrates strain in the lower-modulus CE-BK region and forces the interface to transfer load. Tensile bars cut from the composite are therefore not comparable to homogeneous CE-BK tensile bars. Qualification should use ASTM D412-16 die C specimens with the interface centered in the gauge length and record the failure location. Tear testing should use ASTM D624-00(2020) die B or die C, but the torn path may preferentially follow the interface unless the interface has been designed with mechanical interlock. Interfacial peel testing can follow ASTM D6862-11 or a 90° peel fixture with a 10 mm wide interface. Published data for interfacial strength in this specific product is limited; production qualification builds should include a peel coupon and a hardness plaque in the same build lot. The elastomer-region durometer is measured on a 6.0 mm thick plaque using ASTM D2240-15e1 with a 5 s reading time. Thinner plaques may produce artificially high readings because the rigid backing or adjacent clear phase carries part of the indenter load.

In medical or wearable housings where skin contact is intended, the material set must be assessed for biocompatibility according to the application-specific standard. The manufacturer safety data sheet and compliance declarations should be consulted for REACH 1907/2006 and RoHS 2011/65/EU status before use in regulated devices. The trade designation alone does not establish USP Class VI or ISO 10993-5 cytotoxicity compliance. Such documentation must be requested for the specific material set, printed geometry, and post-processing protocol.

The production bottleneck is not jetting but support removal in the M2 SUW wax

On the ProJet MJP 2500 Plus platform, the RCL-EBK-A70 material set is run with M2 SUW support material. The support wax is removed in a temperature-controlled oven at a setpoint near 60 °C. The clear rigid phase and the black elastomer phase have different thermal expansion and mechanical constraint during heating. A large flat rigid section bonded to a thick elastomer section can warp during support removal if parts are removed from the oven while the elastomer is above its room-temperature recovery state. The protocol should allow parts to cool below 30 °C before removal from the support tray. Wax retention is more common in elastomer-dominated regions because the soft surface allows molten wax to remain trapped in blind holes, internal channels, and undercuts. Field experience on MultiJet Printing systems shows that blind channels below 2 mm diameter in CE-BK regions require extended oven cycles or manual hot-water rinsing, and support removal time can increase by 30–60 min relative to a single-material rigid build of the same envelope. Ultrasonic or pressurized water-jet removal is not universally recommended because the elastomer phase may absorb mechanical energy and degrade or swell at the interface. Build chamber conditions and cartridge conditioning should follow the platform manual. The native layer thickness of 32 µm sets the minimum Z-feature discretization, but practical minimum feature size in elastomer regions is usually larger because support material must penetrate and later drain from fine channels.

For short-run gripper and end-of-arm tooling prototypes, the composite is used to place rigid CR-CL 200** mounting flanges and black CE-BK gripping pads in a single build. This removes the need to bond die-cut rubber sheets to machined aluminum fixtures. However, the product is not a direct replacement for production polyurethane gripper pads. Gripper pads made from CE-BK should be tested under ASTM D575-91(2020) compression-deflection and ASTM D395-18 compression set to confirm that the printed material withstands the required clamping force and duty cycle. Because the elastomer phase is a UV-curable jetted material rather than a cast thermoset polyurethane, tear strength and compression set may differ; published data for this configuration is limited. The clear rigid flanges should be checked for dimensional accuracy against the manufacturer-specified MJP tolerance, with verification on the printed part because dual-material builds can introduce local shrinkage mismatch. If the gripper pad requires food-contact compliance, the manufacturer should be consulted for FDA 21 CFR 177.2600 or EU 10/2011 documentation for the specific material set; the trade designation alone does not establish food-contact status.

Ball-and-socket protective housings and wearable device prototypes use the material set to print a clear rigid shell in CR-CL 200** and a black elastomeric flex hinge in CE-BK. The geometry creates a living hinge that is not evaluated by a single material standard. Flexural fatigue should be tested with a custom fixture based on ISO 4666-3:2020 or ASTM D7774-17 at the intended strain. Because the hinge is a printed elastomer domain between rigid clear anchors, crack initiation occurs at the domain boundary if the transition radius is too small. A minimum corner radius of 1.0 mm at the rigid-elastomer transition is recommended for initial prototypes; exact values should be determined by build trials. The MJP process can produce the hinge in the same layer orientation as the part, so anisotropy is generally lower than in extrusion-based flexible prints, but layer orientation remains a factor in tensile and fatigue results because the droplet interface network is not identical to a cured bulk elastomer.

If the application demands chemical resistance, the composite must be tested against the process fluids

Chemical compatibility is not established by the A70 suffix. The CR-CL 200** clear phase and CE-BK elastomer phase may have different resistance to oils, acids, alcohols, and ketones. Where the product is used in gaskets for fuel or solvent systems, exposure tests should follow ASTM D543-21 or ISO 175:2010 and record mass, dimensions, Shore A, and tensile strength after 72 h at the service temperature. Aggressive cleaners or vapor degreasers can attack the elastomer phase. Chlorinated solvents should be avoided unless test data support the exposure. Compatibility with aqueous coolant, glycol, and mineral oil should be tested in the specific concentration and temperature range before production release. The interface is especially susceptible to solvent wicking because capillary gaps at the material boundary can retain fluid and promote swelling. Sealing a printed part with a low-viscosity coating may reduce wicking but changes the surface hardness and should be re-qualified with ASTM D2240-15e1.