3D Systems VisiJet RBK-RWT-L70 Multi-Material Composites is a paired-cartridge photopolymer product comprising VisiJet CR-BK and VisiJet CR-WT 200**. The product is intended for multi-material rigid part builds on multi-jet modeling systems that support separate black and white resin channels, heated reservoirs, and independent recirculating printheads. The RBK-RWT-L70 designation identifies a build-material set rather than a pre-mixed resin compound; black and white regions are formed from discrete droplets that cure into adjacent rigid domains within a single build. Published material-specific mechanical property ranges for this exact pairing are limited, and the following technical treatment is therefore focused on standard-test applicability, processing boundaries, and equipment-level failure modes common to pigmented rigid MJP photopolymers of this class.

Build resolution is not specified by the resin kit alone; it is a function of the printer’s droplet volume, address grid, and layer thickness. Multi-jet platforms used for rigid photopolymers commonly operate at layer thicknesses between 16 µm and 32 µm, while the exact XY resolution and jetting waveform are embedded in the supplier’s material parameter file. The kit is supplied as two liquid photopolymer cartridges, one pigmented black and one pigmented white, and is identified in printer software as a multi-material build pair. The material set is designed for multi-jet modeling workflows that use a planarizer to level each jetted layer and then expose the layer to UV energy before the next pass. In such systems, the black and white resins are deposited through separate printhead channels but are not blended in the fluid path; any color transition is created by geometric assignment in the build file. Because the two resins may not have identical shrinkage, the part file must be compensated with independent scale factors for each shell, and the operator must verify that the printer’s firmware has loaded the correct material parameter files for both cartridges.

What Distinguishes the CR-BK / CR-WT 200 Pairing from Single-Resin MultiJet Materials?

Unlike single-cartridge rigid VisiJet grades, this set requires a printer configuration with two build-material pathways and the software capability to map black and white shells to separate payloads within one 3MF or STL assembly. The printer must schedule purge and material-change events at the beginning and end of each region, and the operator must verify that both resin channels hold stable meniscus pressure before the first layer. The material set is not a soluble support system, not an elastomer, and not a burnout casting resin. It also does not produce a continuous polymer gradient; the black-white boundary is a bonded photopolymer interface created by partial cure overlap between successive droplets. Selection should be limited to applications where the part function depends on rigid contrasting regions—tooling fixtures with visual datum features, inspection aids, training models, or multi-color housings for non-structural units. Compared with a single-material rigid build, dual-material jobs generate additional non-productive time during cartridge changeovers, and the interface must be treated as a separate inspection zone rather than as a bulk property of either resin.

The main operational difference from a single-resin build is the presence of purge volumes at the transition. These purge volumes are not negligible; the process planner should enter a known waste allowance into the part cost model and compare it against the cost of post-mold assembly of two single-material components. On multi-jet platforms where both cartridges feed a common recirculating channel, cross-contamination at the transition is managed by a cleaning interval. If the cleaning interval is shortened below the manufacturer’s validated minimum, pigmented resin droplets may contaminate the opposite region and produce optical as well as mechanical variability. The black resin may require a longer purge after idle periods, since dispersed pigment can settle more readily than in the white resin. An extended idle period before a transition should therefore be followed by a purge cycle of the full dead volume between reservoir and printhead.

Cartridges are sealed and ready to load; mechanical shaking is not required. In production environments with relative humidity above 60 %, cartridges and their septa should be equilibrated to the printer bay temperature before opening to prevent condensation on the resin-level sensor or fill port. Solvent wipes used on the cartridge data chip or feed line fittings must be approved in the manufacturer’s material-handling guide; ketone- or chlorinated-solvent contact with the wetted interface can embrittle polymer seals and introduce wiper-film contamination.

Nominal Part-Qualification Property Matrix and Standard Designations

For supplier-independent qualification, rigid MJP photopolymer specimens are conditioned according to ASTM D618-21 at 23 ± 2 °C and 50 ± 10 % RH for not less than 40 h before testing. Print orientation, post-cure dose, and the number of build plate witnesses must be recorded because photopolymer anisotropy can shift the numerical result. The following matrix identifies the standard designations routinely used for this material class; the supplier’s current technical datasheet remains the authoritative source for accepted values of VisiJet CR-BK and VisiJet CR-WT 200**.

Lot acceptance for this family of materials is often reduced to a small property set—jetting-temperature viscosity, density, Shore D hardness, tensile yield stress, and elongation at break—rather than a full certification campaign. Where a downstream specification includes flexural modulus by ASTM D790-17, flatwise and edgewise specimen sets should be treated as separate populations until a product-specific equivalence study demonstrates otherwise. Layered photopolymer sidewall striations can reduce edgewise modulus repeatability even when bulk conversion is complete. The tensile, flexural, impact, and thermal deflection standards listed above are screening methods common to MJP photopolymer datasheets, but they do not define the interfacial strength of black-white regions. Users should generate an additional test block containing a straight black-white boundary across the gauge section, and then measure it under a suitable adopted standard; this is the only way to separate composite behavior from bulk material behavior.

When Dimensional Inspection Uses ASTM D638 Type IV Specimens and CMM Datum Order

When dimensional inspection is added to a dual-material build, the measurement plan must establish datum precedence before support removal. 3D Systems print preparation software assigns a facet-based coordinate system; after extraction, coordinate-measuring machine alignment on black feature datums may differ from alignment on white feature datums if the two resins exhibit different shrinkage compensation factors. Footprint density, support density, and post-cure orientation should be held constant across qualification lots. Features that cross the black-white interface should be dimensionally inspected before any solvent wipe, because a solvent that swells one resin more than the other can open the interface or shift the apparent boundary. The interface itself should not be used as a functional datum unless the supplier has published a geometric tolerance study for this exact pairing. Destructive cross-sections at the interface typically show a distinct boundary band under magnification; the band is created by overlapping cured volume elements and does not indicate polymer interdiffusion.

Because white and black photopolymers exhibit different optical penetration depths at the curing wavelength, the cure depth at the interface can be wider on the white side than on the black side. This can create a small asymmetric overlap zone. A precision cross-section, rather than a surface trace, is required to define the boundary for tolerance-stack calculations. For parts with an inserted metal thread or insert, the interface should be placed away from the high-load side of the insert boss; placing it in line with the clamp-force path can produce premature edge chipping during torque testing.

During long production runs, automatic cartridge changeovers and low-liquid sensors generate pause-and-purge events that may shift layer registration at the black-white transition. The operator should record event timestamps, heater setpoints, and planerizer wear intervals because these variables affect cross-material edge definition more than bulk mechanical properties. Recirculating printheads with a failed meniscus vacuum can entrain gas at the flow boundary; intermittent nozzle loss then appears as linear voids along the scan axis. When such voids cross the interface, tensile elongation by ASTM D638-14 on a homogeneous coupon is not a valid indicator of interfacial ductility. A bonded lap-shear or peel specimen taken from the same build plate provides the relevant interfacial measurement. In the absence of a product-specific interface strength specification, witnessed coupons should be destructively tested before committing to production lots.

Batch-to-Batch Viscosity Drift and Recirculating Inkjet Shearing

VisiJet CR-BK and VisiJet CR-WT 200** are processed at elevated printhead temperature to reduce viscosity into the jetting window. Inkjet-grade photopolymers of this class are typically formulated to 8–20 mPa·s at jetting temperature, with exact setpoints embedded in the printer’s validated parameter file and not editable on the production floor. Even a shift of less than 1 mPa·s can change drop velocity, satellite formation, and final layer thickness in high-frequency piezoelectric arrays. Cartridges from different lots should not be blended within a channel unless lot-specific viscosity, surface tension, and pigment dispersion density have been checked. Recirculation loops with 5 µm absolute filtration protect the printhead from coagulated pigment; an increase in pressure drop across the filter is an early indicator of dispersion breakdown. Production records frequently show a larger viscosity rise for pigmented black resin than for white resin under sustained reservoir temperature because of dispersed pigment settling and thermal ageing. This differential can require different cartridge pre-heat times before the first layer is printed.

The equipment compatibility requirement extends to the planerizer blade. Blade wear at the interface can cause resin carryover from one region to another, producing hazy boundaries. Production logs from MJP machines running pigmented sets often show that planerizer replacement frequency must be increased compared with clear or white-only jobs because pigmented material can increase abrasive wear of wiper edges. The blade gap and roll speed are set by the printer’s maintenance routines; any field adjustment to compensate for material carryover should be made only after measuring the layer stack height with a contact profilometer.

Among cartridges stored at the line, the black resin is more sensitive to pigment sedimentation after extended idle periods. The cartridge should be conditioned to jetting temperature for the supplier-specified duration and purged through the printhead until the meniscus is stable. Solvent immersion testing after post-cure is not part of routine lot acceptance; if a final article will be wiped with isopropanol, a 24 h immersion or wipe-cyclic test at 23 ± 2 °C should be added to the part qualification plan because residual low-molecular-weight photopolymer fractions can plasticise the surface and alter dimensional recovery.

Without a post-cure chamber dose of known radiance uniformity, side-by-side black and white sections can exhibit differential shrinkage because carbon-black pigmentation attenuates curing light at the exposed surface while white pigmentation reflects and scatters light over a longer path length. Cure stations should be mapped with a radiometer calibrated to the LED or discharge source wavelength listed in the supplier’s process bulletin; the chamber’s dose non-uniformity should be kept within the range stated by the equipment manufacturer. Component surfaces facing the lamps may cure faster than vertical sidewalls, and a part rotated during post-cure will show less distortion than a stationary one. The presence of dark regions adjacent to white regions can create local thermal gradients from absorbed optical energy during cure; therefore, optical pyrometer checks of the part surface should be made after removal. If no product-specific limit is available, it should not be assumed that black and white regions reach the same chamber temperature.

Auditing the Regulatory File Before Introducing the Kit to Production

Regulatory documentation should not be accepted as a proxy for mechanical qualification. The following checklist supports shipment and import review for a production line that will stock both VisiJet CR-BK and VisiJet CR-WT 200** in the same printer envelope.

Regulatory files do not replace mechanical qualification. A production line using both black and white resin should retain per-lot SDS revisions, cartridge lot numbers, and build parameter file versions. If the product is exported, the receiving entity must verify that the photopolymer chemistry meets local industrial chemical inventories; data for this exact pairing should be read from the supplier’s regulatory information bulletin. No claim of food-contact, medical, or implant body compatibility is made in this entry.