The 3D Systems VisiJet RBK-RCL-L50 Multi-Material Composites part number identifies a paired rigid photopolymer set consisting of VisiJet CR-BK and VisiJet CR-CL 200. The designation does not refer to a particulate-filled composite resin; it refers to the ability to deposit two rigid materials with contrasting optical densities in a single MultiJet Printing build. VisiJet CR-BK supplies opaque black regions, and VisiJet CR-CL 200 supplies optically clear regions. The material set is qualified for the specified MultiJet Printing platforms that support the paired configuration, using the designated wax support material and a 32 µm layer thickness in high-definition mode where specified. The paired cartridges are intended for prototypes and short-run production where transparent inspection windows, fluid channels, or black structural bodies must be produced without adhesive bonding, snap fits, or overmolding.

What separates the RBK-RCL-L50 configuration from single-phase rigid photopolymers?

Single-rigid MJP builds require the entire part volume to be one material unless secondary bonding is used. The RBK-RCL-L50 set permits the deposition of opaque black and transparent clear photopolymers in a single build sequence, with the interface between the two materials formed by jetted droplets that are UV-cured in the same layer pass. Unlike overmolding, the multi-material transition is built in the same machine rather than transferred between tools. The resulting interface is not a mechanical interlock or adhesive bond; it is a photopolymer network formed from two different resin chemistries that share a common build platform and support system. The primary processing difference is that the printer must manage two part materials plus a support material, which reduces the available build envelope in multi-material zones relative to single-material builds using the same platform. Because each material has a distinct viscosity-temperature response, the jetting parameters must remain within the waveform settings specified by the manufacturer. In multi-material regions, the transition boundary is generated from the STL or 3MF mesh; arbitrary voxel-level blending is not available unless the software and material licence enable that function.

The simultaneous deposition of opaque black and transparent clear resins creates a jetted interface that is not a simple planar boundary. At each layer, the printer controls droplet placement at the transition according to the bitmap of the input file. If the boundary crosses a layer plane, the printed edge can have a stair-step profile. This stair-step may appear as a visible line in the clear region and can act as a stress riser when the multi-material part is loaded in bending. To reduce the optical defect, the user can adjust the part orientation so that the transition runs parallel to the z-axis or increase the number of shell layers in the transition zone. These actions increase build time and may reduce the effective clear aperture because more opaque droplets occupy the boundary region. The user should inspect the transition under 10 x magnification after support removal and, if optical clarity is critical, specify the transition as a thin bond line rather than a large continuous clear-to-black aperture.

In the as-printed, support-removed condition after conditioning at 23 °C ± 2 °C and 50 % ± 5 % relative humidity, representative mechanical values for the two materials are summarized in the table below. The values are typical datasheet values, not minimum performance specifications. Because MJP photopolymers are thermoset, melt flow index testing per ISO 1133-1:2022 is not applicable. The table values should be used for material selection only; part qualification must include testing of the actual build orientation and support-removal history.

Mechanical response is orientation-dependent. Tensile specimens printed in the z-axis often show lower elongation and modulus than x-y plane specimens because of the layer-wise fusion boundary. The supplier recommends testing parts in their intended build orientation; datasheet values are derived from x-y plane specimens unless otherwise stated. The glassy thermoset character restricts the use of the material set in snap-fit features requiring high post-yield deformation. Living hinge design is not recommended because the material exhibits brittle fracture at stress concentrations under cyclic loading. The clear material may also show local haze at the clear-black transition if the build includes steep transitions or if support removal temperature is too high. Because the two materials exhibit similar but not identical heat deflection temperatures, a multi-material part under thermal load may distort non-uniformly at the clear-black transition. Published data for the coefficient of thermal expansion of the RBK-RCL-L50 paired interface is limited; the user should measure expansion on printed specimens if thermal excursions exceed 40 °C.

Compared with the VisiJet M2R-CL/BK pair used on other MJP platforms, the CR-CL 200 / CR-BK set is formulated for the ProJet MJP 2500 and 2500 Plus material portfolio and is generally positioned for visual contrast rather than high-temperature load-bearing. VisiJet M2S-HT90 is specified for higher heat deflection performance where sustained thermal load exceeds 60 °C; the CR-BK and CR-CL 200 materials are not the appropriate choice for under-hood automotive components or hot fluid circuits without testing. Compared with single-material clear VisiJet CR-CL 200, the paired set does not raise the mechanical properties of the clear material; it adds the ability to combine clear and opaque black regions in one build. Compared with particulate-filled composite photopolymers, the RBK-RCL-L50 material set is not a filled resin system and does not require progressive cavity mixing or abrasive nozzle maintenance typical of filled materials.

When transparent clear regions and opaque black structure must coexist without secondary bonding

Typical use cases include fluidic manifold prototypes, anatomical models, electronic enclosures with clear lens windows, and assembly fixtures where visual confirmation of part engagement is required. In a fluidic manifold, VisiJet CR-CL 200 can form the channel walls, while VisiJet CR-BK forms the manifold body; the fluid path remains visible through the clear material. In medical models, the clear material represents tissue or organ boundaries, while the black material represents bone or pathology. The material set is not indicated for long-term implantable use and has not been qualified under ISO 10993-1 for biological evaluation unless the user performs the necessary testing. Published data for prolonged contact with biological fluids in this specific paired configuration is limited. For electronic enclosures, the user must verify flammability requirements per the appropriate UL 94 classification; published data for the paired configuration as a finished enclosure is limited and should not be assumed from the unfilled resin alone.

For assembly fixtures, the rigid black-body material provides dimensional reference surfaces, while the clear material allows backlit inspection of component seating. Fixture accuracy is influenced by z-axis thermal shrinkage and support removal. Shrinkage compensation factors are available in the printer software, but they are sensitive to part orientation and surrounding mass. Tighter dimensional tolerances require process capability studies on the specific machine rather than reliance on published typical values. The clear-black transition region is evaluated by tensile pull tests across the interface, but the supplier does not publish a single interfacial strength value for the RBK-RCL-L50 pair. Users requiring structural continuity across the transparent-opaque boundary should print test specimens that replicate the transition orientation and cross-sectional area, then perform tensile testing per ASTM D638-14. Because the interface may contain a narrow interpenetration zone formed by successive droplets, the local mechanical response is not identical to the bulk material on either side. The transition should not be used as a living hinge or as the sole load path in assemblies where failure could cause personal injury.

Support removal, storage, and post-processing limits

Support removal uses the wax support material specified for the MJP platform, typically through a heated oil bath or oven followed by ultrasonic cleaning. The precise time-at-temperature is controlled by part wall thickness and internal channel size. Small-diameter clear channels may retain molten support if the oil bath temperature is below the wax melting point or if internal undercuts restrict drainage. Support retention in blind channels is a known failure mode when drainage geometry is inadequate; inspection under transmitted light is recommended after support removal. Storage of cartridges should maintain the environmental range specified in the safety data sheet, typically 15 °C to 25 °C and away from UV sources. The material is not certified for steam autoclave cycles; repeated exposure to 134 °C saturated steam may cause surface haze, dimensional drift, and hydrolytic degradation of untested clear regions. If abrasive tumbling is used, the glassy material may chip at thin edges, and clear regions will lose optical transparency without a subsequent clear coat or polishing sequence.

Immersion tests following the general framework of ASTM D543-20 show that unfilled rigid photopolymers of this class have limited resistance to ketones, chlorinated solvents, and strong alkalis. Short-term wiping with isopropyl alcohol is typical for cleaning after printing, but prolonged immersion can soften surfaces and reduce hardness. The clear material is especially susceptible to visible crazing after exposure to solvent vapor. If chemical exposure is anticipated, the user should expose test coupons in the same build orientation to the intended service chemicals rather than relying on generic compatibility charts. Colour changes in the clear material after prolonged UV exposure can be monitored by spectral transmission; a transparent region exposed to continuous UVA may yellow within weeks if unprotected. Users requiring optical stability should use a UV-blocking clear coat or select a different optical material; published data for outdoor weathering of this material set under ISO 4892-2 is limited. The material set is supplied with safety data sheets; compliance with RoHS Directive 2011/65/EU and EU REACH depends on the finished article and any post-processing additives, and should be confirmed against the current supplier documentation. The cartridges are sealed and should not be opened outside the machine environment to avoid premature photopolymerization from ambient UV and contamination of the inkjet nozzles.