3D Systems VisiJet RBK-RCL-L20 Multi-Material Composites are supplied as a paired photopolymer set consisting of VisiJet CR-BK and VisiJet CR-CL 200. The set is intended for MultiJet Printing platforms that co-deposit two rigid photopolymers with wax support at a nominal layer thickness of 20 µm. The RBK-RCL portion of the designation denotes a rigid black/rigid clear pairing rather than a blended resin, and the 200 suffix on the clear component identifies the CR-series material generation. The kit is not a post-mixed alloy, a two-component thermoset, or a single-material color variant; it is a discrete two-material build strategy for monolithic parts that require opaque and transparent regions in the same printing cycle.

Representative part configurations include optomechanical housings, fluid-manifold inspection windows, sensor apertures, light-blocking covers with clear status indicators, and consolidated assembly fixtures. The use of two discrete materials replaces adhesive joining for selected designs but introduces an interfacial boundary that must be treated as a separate performance region. Suppliers’ datasheets for the individual materials may not describe the strength of that boundary. Published data for this specific configuration is limited, and designers should not extend single-material tensile, flexural, or impact values to the CR-BK/CR-CL 200 interface without printed validation coupons.

Property data for the individual materials in the RBK-RCL-L20 set are not necessarily transferable from earlier M2R-series resins. The CR designation in 3D Systems VisiJet materials is associated with later-generation rigid photopolymers, but the specific datasheet for VisiJet CR-BK and VisiJet CR-CL 200 must be referenced for tensile, flexural, impact, heat deflection, and water absorption values. In the absence of published multi-material interface data, material selection should treat the CR-BK/CR-CL 200 boundary as an untested structural element. That boundary is not a welded joint, a solvent bond, or an adhesive bond; it is a photopolymerization-induced interphase that depends on droplet overlap and cure history.

Material handling for RBK-RCL-L20 follows the MJP wax-supported workflow. Resin bottles are installed in the printer’s material bay after warming to the build environment; printhead, wiper, and waste systems must be dedicated or purged according to the platform protocol because cross-contamination between the two materials can deposit black pigment in clear sections or clear oligomer in black sections. The clear component is more sensitive to bulk color contamination than the black component, and visible color carryover in the clear material is a common indicator of inadequate purge between material changes.

Does the CR-BK/CR-CL 200 interface require a different post-cure regime than single-material parts?

The interface between MJP photopolymers is produced by successive droplet deposition and UV exposure, not by mixing. At the boundary, cure conversion is influenced by photoinitiator diffusion, oxygen inhibition, light attenuation from the black pigment, and layer time. These factors can produce a lower-conversion zone in the first material when the second material is jetted. The printer’s standard post-cure is therefore not automatically sufficient to homogenize the interface. If the supplier has not published an interfacial adhesion test value under ASTM D3163 or ISO 4587, no bulk tensile value from ASTM D638-14 or ISO 527-2 should be substituted. Production runs often reveal that interfacial delamination appears only after thermal cycling or solvent exposure, not in as-built inspection.

Multi-material parts should be oriented so that the interface is not placed at the maximum shear plane and so that clear regions are not printed against flat black regions with an abrupt transition without mechanical interlock. Where the design allows, a stepped or dovetailed interface with a minimum feature size above the droplet placement tolerance can increase interfacial contact area and reduce peeling stress. The droplet placement tolerance for the target MJP platform should be taken from the equipment calibration report; a relatively narrow transition band may be used for functional prototypes, but the exact value must be validated on the specific machine and layer mode.

Post-cure in an MJP workflow is typically performed after support removal, using a UV flood chamber. The black material, because of pigment absorption, can require longer exposure than the clear material for the same surface cure. In a two-material part, this creates a processing conflict: the clear window may be exposed to excessive UV while the black section reaches full conversion. Excessive UV exposure in clear photopolymers can shift yellowness index, embrittle thin walls, and reduce tensile elongation. The process window is therefore a balance between under-curing the black and over-curing the clear. Where the supplier has not published a multi-material post-cure schedule, the user should run a matrix of post-cure times and measure tensile strength, yellowness index according to ASTM E313, and heat deflection temperature before committing to a production recipe.

Support-material removal from multi-material parts is often more thermally demanding than from single-material parts because the two photopolymers may differ in coefficient of linear thermal expansion. During the oven step, differential expansion can open microchannels along the interface and trap molten wax. The use of an ultrasonic bath with the manufacturer-approved rinse fluid can reduce wax residue in inaccessible clear channels. Solvent selection requires chemical compatibility screening under ASTM D543 because aggressive rinses can haze the CR-CL 200 regions or swell the CR-BK surface. If the rinse bath temperature is too high, the black/clear interface can soften and separate. The support removal protocol for multi-material parts often differs from the single-material default; operators may need to reduce oven ramp rate or increase the number of ultrasonic rinse cycles. A documented process validation should include cross-sectional microscopy of the interface for voiding, wax inclusion, and clear-layer delamination.

When a fluid monitoring manifold combines CR-BK housings with CR-CL 200 observation windows

In a fluidic manifold application, CR-BK can form the opaque body and threaded ports, while CR-CL 200 is used as an observation window. The monolithic multi-material build removes the need for an O-ring-sealed glass window and secondary adhesive; however, the transparent region remains a rigid photopolymer with finite elongation at break and solvent sensitivity. Internal leak testing under ISO 7-1 or ASTM F2095 should be performed at the intended service temperature and pressure. Because the two materials may have different tensile moduli, internal pressure can localize expansion at the clear window and transfer interfacial stress to the black housing. Published data for this specific configuration is limited; prototype validation under representative pressure, temperature, and fluid chemistry is required before use in pressurized systems.

Chemical compatibility of the clear material with process fluids must be evaluated under ASTM D543. Ketones, chlorinated solvents, and strong amines are expected incompatibilities for many rigid photopolymers and should be screened as reject criteria. The black material may be less visibly affected by color-stable fluids, but chemical attack may still reduce tensile strength at the interface. Continuous immersion at elevated temperature is a more severe condition than intermittent splash exposure; service life predictions must be based on immersion data, not short-term wipe tests.

The L20 mode at 20 µm layer thickness is selected where layer-step visibility in clear regions must be minimized. Transparent sections at a larger layer thickness can show visible striations that reduce optical clarity. However, the clearer surface may still require sanding, clear coating, or polishing to reach transmissive inspection quality. If a clear-coat system is used, adhesion should be tested under ASTM D3359 because surface energy differences between CR-BK and CR-CL 200 can affect paint and coating wetting.

Material qualification standards and documented boundaries for the RBK-RCL-L20 set

The standards listed above are bulk material methods. They do not remove the need for printed interface coupons because the interface is a process-dependent boundary layer rather than a material property. For multi-material assemblies, test coupons should be built in the same orientation, with the same interface location, and on the same printer as the production parts. A deviation in layer time, printhead age, or support-material batch can change interfacial conversion and invalidate prior qualification data.

Compared with single-material VisiJet MJP resins such as M2R-BK, M2R-CL, or M2G-CL, this kit is not a single resin with colorant; it requires the build processor to manage two material IDs, two printheads, and two temperature setpoints. Compared with PolyJet digital materials that can blend base resins to create grayscale or durometer gradients at the printhead, the RBK-RCL-L20 set generally maintains discrete boundaries and does not produce a continuous modulus transition. These differences matter when designers require a functional gradient or an elastomeric-to-rigid sequence: the RBK-RCL-L20 set is not a substitute for a digital mixed-material system. Published data for graded interface behavior in this configuration is limited.

Unlike cast urethane two-part systems that can be vacuum degassed to remove bubbles, the MJP process entrains no bubbles but can deposit small satellite droplets at jetting edges. These satellites can appear as particulate haze in clear sections and as surface texture on black sections. Printhead maintenance, wiper blade replacement, and printhead-to-printhead alignment are critical for the clear material. In single-material MJP builds, a single misaligned printhead may not be visible; in two-material builds, the boundary makes misalignment immediately apparent.

Storage and shelf-life controls are established by the supplier’s Safety Data Sheet and product label. The clear component may be more sensitive to stray light and to resin temperature excursions than the black component. Bottles should be kept sealed and protected from direct UV and high relative humidity; after cold shipment, bottles should be equilibrated to the build environment before opening to avoid condensation. Printhead drop-mass and drop-speed checks should be performed whenever a new lot is installed because lot-to-lot variation in pigment dispersion can shift the jetting waveform. If a drop-mass outlier is observed, the material should not be mixed with a previous lot in the same reservoir without a documented batch acceptance test.

Parts built from CR-BK and CR-CL 200 composites are frequently used for consolidated electrical enclosure covers, sensor inspection windows, and flow-visualization manifolds. The black regions block stray light, while the clear regions transmit visible light for camera or LED inspection. Designers must specify print orientation and interface position on engineering drawings because the tensile, impact, and optical properties of MJP parts are anisotropic. If the service load includes repeated flexure, impact, or thermal shock, multi-material coupons should be tested under the appropriate ASTM D638, ASTM D256, or ASTM D648 method as applicable. If no supplier-published data for the interface exist, published data for this specific configuration is limited and the design must be validated empirically before production release.