3D Systems’ RBK-RWT-L40 is a paired-cartridge multi-material package for the ProJet MJP 2500 and ProJet MJP 2500 Plus MultiJet Printing platforms. The package combines VisiJet CR-BK, a rigid black photopolymer, with VisiJet CR-WT 200, a rigid white photopolymer. The two constituents are not blended before jetting; each is delivered through a separate heated ink channel and combined only at the part surface as discrete voxels. The L40 suffix is a packaging and logistics identifier for the cartridge set, not an independent material grade. The kit’s principal machine constraints are the platform net build volume of 294 × 211 × 144 mm and standard layer thickness of 32 μm. The native addressable resolution of the MJP 2500-series planar printhead is 800 × 900 × 790 dpi. That voxel addressability defines the smallest practical feature but does not guarantee that black/white transitions will hold that same pitch. Intended applications are rigid, high-contrast enclosures, assembly jigs, colour-coded fixtures, packaging mock-ups, and short-run production aids where black regions indicate wear surfaces or operator-contact areas and white regions carry printed labels. Because both constituents are rigid, the interface does not produce an elastomeric living hinge.

The double asterisk attached to CR-WT 200 in the literature is a product-documentation marker rather than a mechanical property class. The kit is governed by the two constituent technical data sheets, the MJP 2500-series material-matrix release note, and the cartridge-specific safety data sheets. The printer reads both cartridge identifiers at insertion and will not enable a multi-material job unless the RBK-RWT-L40 combination is satisfied. If one cartridge is removed, the job falls back to single-material rules or stops, depending on the job file. This is an operational control that prevents single-channel substitution when black or white inventory is depleted.

What limits the usable envelope when black and white regions occur in the same layer?

Intra-layer black/white switching reduces the effective build width by a firmware-defined purge zone. The transition path is not a fixed dimensional subtraction; it varies with the number of switches per layer and the length of the inactive nozzle row that must be refreshed. When the part places black and white domains only in separate Z-levels, the width loss is negligible because each layer remains single-material. When a single layer contains both colours, each transition requires the printhead carriage to pass through a maintenance purge sequence, and the edge location can be slightly offset. If legibility of fine black text is critical, a two-voxel guard is a practical design allowance; at native 800 × 900 dpi XY addressability this corresponds to approximately 64 μm. Dimensional verification of the final transition boundary should be conducted against ISO 1101:2017 or ASME Y14.5-2018, using a first-article coupon with known black/white adjacency. The boundary defect of concern is not bulk delamination but a mixed-voxel zone in which both materials are partially jetted and cured. The exact transition width is not published for this specific kit; published data for this configuration is limited. Machine operators can derive it indirectly from the material-use report and a dimensional comparator. Because the mixed zone can have a slightly lower Shore D response than either parent material, highly stressed features should not place a structural seam directly on the colour boundary.

Post-processing starts with support removal in a controlled heating station that melts the wax-based support. The two rigid materials do not require post-cure, unlike some filled photopolymers that require a secondary UV or thermal cycle. The waxy support residue should be fully removed before dimensional inspection; residual wax can mask a transition boundary and artificially alter dimensional readings under ISO 1101:2017. Support-removal cycle time is equipment-specific but should be kept within the manufacturer’s protocol because prolonged heating can affect thin black sections differently from thicker white sections. After cooling to ambient, parts can be machined, drilled, or bonded. Adhesive and coating compatibility should be evaluated according to the supplier’s protocol or ASTM D2093/D2093M-11 for surface preparation; solvent wiping should be limited to approved agents because ketone- or acetate-based cleaning fluids may swell the cured photopolymer surface. No food-contact, medical-grade, or pharmaceutical clearance is automatically assigned by the kit designation.

Mechanical characterisation and documentation matrix for the two constituent cartridges

Mechanical property values are published in the current 3D Systems technical data sheets for the individual constituents. Values are lot-specific and should not be transferred from single-material data sheets to multi-material black/white regions without confirming the active cartridge data sheet revision. The table lists the applicable test methods and their relevance to multi-material part design.

Because the kit itself does not carry a single data sheet, part-level destructive testing is more informative than averaging the two constituent data sheets. When small alternating features such as black-on-white labels occupy a significant fraction of a part, the mixed-pixel transition volume can become non-negligible. In such cases, machining tensile or flexural specimens from the same build orientation as the production part and testing according to ASTM D638-14 or ASTM D790-17 provides a stronger basis for design acceptance. Surface roughness across the colour boundary can be assessed with ISO 4287 if the boundary is a functional sealing surface, but published data for this specific kit is limited. First-article measurement is therefore recommended after orientation changes.

When the paired set replaces separate single-cartridge CR-BK or CR-WT 200 in a production cell

Single-material MJP work uses one material channel and one active ink identity. The RBK-RWT-L40 package activates a dual-material job mode and introduces a paired-ID verification. This does not necessarily halve the available cartridge capacity; the two reservoirs deplete in proportion to the printed black:white volume fraction. A part with 90 % black volume will exhaust CR-BK first, and the machine stops the job when either cartridge reaches its lower-limit threshold. Inventory planning for the set must therefore treat the two cartridge levels as asymmetric and not as a matched pair with equal consumption.

The practical build cost also includes purge material. Every intra-layer black-to-white transition sends material to the maintenance station, so the total material usage exceeds the part’s net volume by an amount that depends on the number of transitions. Published data for the purge mass per transition is limited; operators can derive a job-specific figure by comparing the machine’s material-use log with the volumetric CAD model. That derived figure should be inserted into cost-per-part calculations and scheduled waste collection. Production cells running high-contrast label arrays report that lot changes can shift boundary registration by a level visible under magnification. The machine’s closed-loop pressure controller compensates for normal viscosity drift, but pigment dispersion differences between production lots can alter the effective drop mass on the black channel. A lot-change first-article check is therefore an accepted engineering control under ISO 9001 first-article inspection requirements.

In terms of part properties, the black and white regions are not identical mechanical equivalents. The current technical data sheet reports separate tensile modulus, flexural modulus, and HDT entries; the black pigment loading typically produces a different stress–strain response than the white formulation. A structural rib crossing a black-to-white boundary should be designed using the lower published modulus unless an explicit finite-element model demonstrates sufficient margin. This is not a reflection of defect but of pigmentation-induced differences within the same polymer class.

Interfacial failures observed in production cells are most often colour bleed, edge shift, and local hardness depression rather than gross delamination. The two CR formulations are chemically compatible, but when both are deposited into the same voxel region the resulting intermediate mixture has an indeterminate pigment ratio and an undefined data-sheet property set. The safest design treatment is to locate the seam away from tensile surfaces, neutral-axis discontinuities, and snap-fit roots. When a label must remain legible on a curved surface, the text stroke should be increased beyond the single-material minimum feature size by a design allowance of 2 voxels. At native 800 × 900 dpi XY addressability this corresponds to approximately 64 μm, but the exact shift should be confirmed on a first article. Build orientation also affects the quality of the transition. Because the layer thickness is 32 μm, a black-to-white plane that lies exactly parallel to the build platform produces a sharper colour division than a vertical wall in the XY plane, where the combined effects of carriage acceleration and purge timing can produce a slight stagger. This is an operational boundary of the multi-material mode, not a defect unique to the RBK-RWT-L40.

Regulatory obligations for the set are managed at the constituent-cartridge level. A single blended CAS registry does not apply to RBK-RWT-L40, because the materials remain separate until the build plane. Hazard communication, disposal classification, and REACH EC 1907/2006 statements are therefore tied to the individual CR-BK and CR-WT 200 SDS documents. RoHS compliance for electrical and electronic applications is assessed under Directive 2011/65/EU as amended by (EU) 2015/863, and production sites should verify the current declarations for each cartridge lot. The kit is not certified by the designation alone for food-contact, medical, or pharmaceutical use; if those environments are required, the component-level regulatory status must be confirmed before use. The product is also not formulated as a high-temperature engineering resin or as an elastomeric component. Applications that require continuous service above the data-sheet HDT or cyclic flex at a living hinge are outside the operational boundary of this material set. When those boundaries are respected, the RBK-RWT-L40 provides a documented dual-colour rigid platform within the ProJet MJP 2500-series workflow.