The material set designated 3D Systems VisiJet RBK-RCL-L40 comprises VisiJet CR-BK, an opaque black rigid photopolymer, and VisiJet CR-CL 200**, an optically clear rigid photopolymer. The L40 marking indicates a 40 kg supply configuration for multi-material material jetting equipment. The product is intended for production platforms in which piezoelectric printheads selectively deposit two rigid acrylate resins into the same layer, then UV-cure the combined voxel field into a single crosslinked structure. The two resins are not bulk-blended into a homogeneous composite; they are placed as discrete, voxel-defined volumes that produce a continuous solid with both black structural regions and transparent inspection regions.

The intended function of RBK-RCL-L40 is to eliminate secondary bonding or insert molding of black and clear components. In a single-resin workflow, a clear window and a black housing are printed separately, washed, dried, and adhesively bonded; the bond line introduces a separate adhesive interface with surface-treatment dependence. In the RBK-RCL-L40 workflow, the transition between CR-BK and CR-CL 200 occurs before polymerization reaches gelation, so the two networks cure in contact within the same layer. This reduces part count and assembly labor, but it imposes specific controls on printhead purge, layer-time consistency, and support removal.

What Distinguishes the RBK-RCL-L40 Composite Set from Single-Resin VisiJet M2R Media?

Single-resin VisiJet M2R materials produce monolithic parts with uniform mechanical and optical properties. RBK-RCL-L40 produces a non-uniform solid in which the black and clear regions retain separate network densities and optical behavior. The transition is not a welded joint with a discrete heat history, nor an adhesive bond with an organic film; it is a UV-polymerized interpenetrating boundary formed by liquid-liquid contact before acrylate conversion reaches gelation. Compared with elastomeric multi-material sets, RBK-RCL-L40 is rigid. Shore D values for both resins are above 80, whereas elastomeric VisiJet materials are measured on the Shore A scale. This distinction is critical for applications requiring snap-fit compliance or gasket-like deformation.

Table 1 lists representative published datasheet values for the individual resins. The values are single-resin values, not bulk composite values, because the combined mechanical response depends on the geometry, ratio, and orientation of the CR-BK/CR-CL 200 boundary within the part.

Processing Window, Support Removal, and Post-Cure Dependencies in Multi-Jet Printing

The RBK-RCL-L40 materials are low-viscosity acrylate photopolymers. In heated printhead systems, the reservoir set point is controlled to maintain jetting viscosity in a range of 9–15 mPa·s at the nozzle. The exact machine set point is stored in the ProJet MJP 5500X firmware and is not adjusted by operators. The two resins share the same wax-based support medium, 3D Systems VisiJet S500. Support removal for multi-material builds is performed in a heated oven or solvent-assisted bath. The wax softens at temperatures below the heat deflection temperatures of the cured rigid network, but the soak temperature must not exceed 60 °C because HDT values under 0.45 MPa load fall within the 50–60 °C band according to ASTM D648-18. Production lines use circulated-air ovens with temperature uniformity of ±2 °C and part racks that prevent load-induced distortion during wax drainage.

After support removal, UV post-cure is required to reach the published mechanical plateau. Typical post-cure exposure is 2 h per side under a broad-spectrum UVA source. Insufficient post-cure leaves residual acrylate unsaturation and reduces Shore D hardness. Over-post-cure can embrittle thin CR-CL 200 windows. Batch-to-batch release in production is monitored by measuring Shore D hardness before release. A planar CR-CL 200 sample of 6 mm thickness is cured with the lot and measured according to ASTM D2240-15. If the lot hardness falls below 80, the part is re-exposed and re-checked. This procedure is necessary because the dual-material part cannot be destructively tested without losing the transparent regions.

On multi-machine production cells, cross-contamination of CR-BK into the CR-CL 200 channel is a known failure mode. The symptom is a faint grey or black streak in the clear region, detectable under transmitted light but not always under reflected inspection. The defect is not corrected by thermal post-cure. Printhead purge cycles and seal maintenance are required after each material change. Pressure differential across the ink paths is also recorded; a rising differential above the machine alarm threshold indicates filtration blockage or pigment agglomeration. The CR-BK pigment concentrate is milled to a controlled particle-size distribution to maintain jetting stability, but pigment settling in an unrecirculated reservoir can produce spatially variable opacity in the first build layer. The supplier-published shelf life and minimum agitation interval must therefore be observed.

Unopened containers should be stored at 15–25 °C in the dark, with relative humidity below 60%. Before use, containers are conditioned in the printer bay for 12 h to reach thermal equilibrium. Exposure to ambient UV light or sunlight is not permitted because residual photoinitiator can polymerize in the container. Because the CR-BK pigment is suspended, not dissolved, the container is rolled or gently agitated for 10 min before installation. A vented fill is required to prevent air entrapment in the printhead feed line. The resins are not to be mixed with amine-functional surface primers or chain terminators; unintentional introduction of amines can induce premature gelation in the feed path.

When Multi-Material Interface Integrity Governs Part Acceptance

The CR-BK/CR-CL 200 transition is a co-cured acrylate network, but the two phases do not exhibit identical polymerization shrinkage. Differential shrinkage across a flat boundary can generate residual stress, especially in transition features longer than 2 mm along the Z axis. Published interfacial peel data for this specific material pair is limited; part-level validation therefore commonly uses ASTM D638-14 tensile specimens with the material boundary located at the gauge center, tested at 23 °C ± 2 °C and 50% ± 5% relative humidity. The resulting effective tensile strength is not a single material property; it depends on the interfacial area, the orientation of the boundary relative to the tensile axis, and the layer thickness used during printing. Design practice for load-bearing parts places the boundary at an angle between 10° and 30° from the primary load axis, or introduces a dovetail interlock in the opaque region to increase mechanical interdigitation.

Chemical incompatibilities include ketone-based solvents and strong aromatic hydrocarbons; both phases can swell or craze in these environments. Isopropanol wiping should be limited to 30 s exposure. The resins are not designed for continuous immersion in hot water above 50 °C because hydrolytic aging can reduce flexural strength. For service conditions outside these boundaries, validation under the intended end-use environment is required. No statement is made concerning USP Class VI or ISO 10993 biocompatibility; those requirements must be confirmed through a separate regulatory assessment.

Microfluidic fixture bodies and clinical anatomical models are common production uses for RBK-RCL-L40 because the black opaque regions provide contrast and the clear regions allow visual inspection of internal channels or hidden structures. In a microfluidic manifold produced with the printer default high-definition mode, the CR-CL 200 viewing window can be hand-polished with 3 µm diamond paste to reach transmitted-light clarity adequate for 10× optical inspection. The CR-BK housing blocks ambient light and sharpens edge detection in machine-vision modules. The dual-material part may be exposed to aqueous dye solutions at 25–35 °C; the supplier should be consulted for chemical compatibility of specific fluorescent tracers.

Compliance and Test-Method Matrix for the Constituent Resins

Compliance is not a static property of the material set; it is a function of the label, the resin lot, and the shipping configuration. The L40 packaging must contain a batch certificate that references the material codes, the date of manufacture, and the recommended retest date. Incoming inspection records lot-specific density and Shore D hardness; density is measured by Archimedes method according to ASTM D792-20, and hardness is measured with a Shore D durometer after the specified post-cure. If the lot-specific data fall outside the supplier-published band, the material is quarantined before the printer reservoir is filled. This is particularly important for multi-material printers because an off-specification lot in one channel cannot be detected from final part mass alone.