The 3D Systems VisiJet RWT-RCL-R78 Multi-Material Composite is a material-jetting product designation that pairs VisiJet CR-WT 200 rigid white photopolymer with VisiJet CR-CL 200 rigid clear photopolymer in one build. The RWT-RCL-R78 identifier does not denote a blended resin supplied in a single cartridge; it specifies a two-resin build state in which the rigid white phase, the rigid clear phase, and a nominal Shore D hardness target of 78 under ASTM D2240-15 are produced by voxel-level deposition. The composite is processed on the 3D Systems ProJet MJP 5600, which has a build envelope of 518 × 381 × 300 mm and an addressable droplet grid of 1200 × 900 × 790 dpi. Both base resins are UV-curable acrylic ester formulations; the white grade contains an inorganic pigment that limits light penetration, while the clear grade transmits visible light after support removal. Typical applications include transparent flow visualization models, medical device housings with local inspection windows, and fixtures requiring integrated optical contrast without adhesive assembly.

What Process Parameters Dominate the Simultaneous Jetting of CR-WT 200 and CR-CL 200?

Material jetting imposes a narrow viscosity band at the printhead; both feedstocks remain below approximately 12 mPa·s at the operating temperature to permit reproducible droplet formation. The ProJet MJP 5600 deposits the two resins through independent piezoelectric channels, and an ultraviolet source cures each voxel before the build platform indexes downward. When CR-WT 200 and CR-CL 200 are jetted into the same layer, the white pigment absorbs a larger fraction of the incident UV energy than the clear resin. This mismatch creates a local cure-rate difference: white voxels reach gel point sooner, while clear voxels require additional energy or longer exposure. Production-scale behavior on this platform shows that thin sections below 0.8 mm can curl or warp when the white-to-clear volume ratio exceeds approximately 60:40, although published data for this exact configuration is limited. Layer thickness is selectable between approximately 13 µm and 32 µm; the selection changes interface sharpness, build time, and residual stress accumulation. Pigment agglomeration in the white channel is a known processing bottleneck during sustained multi-material runs; idle white channels may require a refresh jetting sequence to prevent nozzle drop-out.

Before printing, cartridges are conditioned according to the manufacturer’s handling datasheet. Typical storage conditions for this resin family fall between 18–25 °C and 20–60 % relative humidity; cartridges inserted below room temperature can produce missing jets and inconsistent droplet volume. Filtration in the MJP fluid path removes particulates above the printhead nozzle threshold, but settled pigment in the CR-WT 200 cartridge can shift opacity batch-to-batch without changing Shore D. A lot-release plaque tested under ASTM D2240-15 is a practical means of verifying the R78 hardness expectation for a specific cartridge pair. Published data for the viscosity-temperature curve of a blended white-clear voxel state is not available; on-machine jetting diagnostics based on drop mass and satellite formation are the primary process controls.

Build orientation is not a passive parameter. Upright clear sections tend to exhibit lower surface haze than downward-facing surfaces because the wax contact layer is removed more completely from upward-facing areas. Downward-facing white sections can retain pigment-rich surfaces after support removal; this changes the measured Shore D. The orientation should be specified on the drawing before printing because droplet landing angle influences interface roughness. On the ProJet MJP 5600, the printhead scan direction and the perpendicular axis have different droplet placement repeatability; the white-to-clear interface is typically sharper parallel to the scan direction than perpendicular to it, although published data for this specific configuration is limited.

Dimensional Stability and Wax Support Removal in Clear-White Composite Geometries

Support removal defines the dimensional stability boundary. The MJP process uses a non-reactive wax-like support material that is removed by heating in an oven or in a heated ultrasonic bath. The wax phase liquifies in the 60–70 °C range. The clear CR-CL 200 domains permit visual confirmation of internal channel cleanliness; the white CR-WT 200 domains obscure residual wax. This optical asymmetry means internal channels should be designed with a clear inspection window wherever possible. When a channel is entirely surrounded by white material, computed tomography or destructive sectioning is required for verification. Dimensional measurements after wax removal are conditioned under ISO 291:2008. The clear phase is more sensitive to thermal soak than the white phase; prolonged oven exposure can relax thin walls and change channel diameters by more than the as-printed layer dimension. Heat deflection temperature is reported for the base resins under ASTM D648-18 at 0.455 MPa, but the composite HDT is not a linear interpolation of white and clear values because the interface region has a different degree of conversion.

Solvent exposure of the cured composite is not equivalent to base-resin immersion data. Ketone-based solvents, aromatic hydrocarbons, and chlorinated cleaners can craze the clear phase and delaminate the white-to-clear interface. Short-term wiping with isopropyl alcohol is common after support removal, but continuous immersion in alcohol-based disinfectants may reduce transparency and soften the white surface. Chemical resistance data are generated under ISO 175:2010; composite-specific chemical exposure data are sparse. For medical prototype validation, the selected sterilant should be tested on the exact white-to-clear ratio because published compatibility documentation for the base resins does not cover multi-material interfaces.

Compared with a single-grade VisiJet CR-CL 200 or CR-WT 200 part, the RWT-RCL-R78 configuration eliminates the need for bonding separately molded transparent and opaque sections. The transition between materials is graded over several voxels rather than a discrete bond line, so one printed piece contains both phases in a single polymerized network. This differs from insert-molded or machined assemblies, where the joint is a mechanical weak point or adhesive layer. Against sacrificial wax pattern resins, the composite is a rigid end-use prototype material, not a burnout or investment-casting medium. Against elastomeric VisiJet grades, the composite is glassy and exhibits limited rubber-like recovery; the R78 suffix targets Shore D 78, not an elastomeric Shore A response. The absence of pigment in the clear phase increases UV penetration depth and can produce higher through-thickness conversion in clear regions than in white regions, shifting the local glass transition temperature. Published data for the glass transition temperature of the exact RWT-RCL-R78 voxel blend is limited; differential scanning calorimetry under ASTM E1356-08 is required before validating the composite for elevated-temperature service.

If Clear Domains Are Used for In-Situ Inspection, Then Layer Thickness and Interface Haze Control the Optical Result

When clear regions are specified for internal visualization, the effective optical clarity is governed by layer thickness, post-processing method, and the proximity of white voxels. Finer layer settings near 13 µm reduce staircase fog on curved walls but create more interfaces where white and clear droplets meet. The droplet grid of 1200 × 900 × 790 dpi does not guarantee a crisp optical boundary because the UV cure front in the clear resin can extend beyond the intended voxel and partially crosslink adjacent white material. Haze is quantified under ASTM D1003-21; bulk haze values for CR-CL 200 alone are not transferable to a composite with dense white features because interface scattering dominates. For microfluidic prototypes with channel spacings below 0.5 mm, engineering specifications should not assume clear-only transparency unless the white phase is separated by several voxel widths from the inspection line. If optical clarity is critical, vapor polishing or clear coating can be applied, but these operations add a secondary material layer and are not covered by the base resin datasheets.

Mechanical response in the composite is anisotropic and position-dependent. A tensile coupon printed entirely from CR-WT 200 cannot represent a composite region with alternating white and clear voxels. Stress concentrates in the lower-modulus clear phase when the part is loaded parallel to the material transition; transverse loading can produce crack deflection at the interface. Izod impact is reported under ASTM D256-23 and notch sensitivity under ISO 180:2019, but these values are only meaningful if the notch location is specified relative to the printed white-to-clear boundary. Rheological data for the base resins are not published as steady-shear viscosity curves; jetting performance is controlled by droplet mass, satellite-free drop formation, and nozzle recovery rather than by a single viscosity specification. Published data for this composite configuration is limited, and production acceptance should include a fixed orientation, fixed layer thickness, and fixed white-to-clear ratio from the actual build file.

Post-cure UV chambers are sometimes used to complete conversion of the clear phase. A process conflict arises because the white phase absorbs strongly and may not respond to the same post-cure dose. If a high-dose UV cycle is applied uniformly, the clear phase can become brittle or slightly yellow before the white phase reaches full conversion. The irradiated energy is reported in mJ/cm² and should be verified with a radiometer; for transparent sections, the process window is narrow at approximately ±5 % of the nominal dose. When the part is post-cured at temperatures above 50 °C, wax residue in blind channels can soften and reflow, contaminating clear optical windows. This is a critical threshold risk in production.

Safety Data Sheets for the individual feedstocks are maintained under REACH and RoHS obligations. The composite printed part is a fabricated article, not a separately registered mixture; regulatory compliance is assessed on the final article configuration. If the part is intended for medical device contact, ISO 10993-1:2018 evaluation is the responsibility of the device manufacturer, and published data for this specific multi-material configuration is limited.

Using the Compliance Matrix for CR-WT 200 and CR-CL 200 Documentation

The following matrix identifies the test methods commonly referenced for the base resins and the limitations when applying them to a blended multi-material state. The absence of a single composite value in the manufacturer’s published datasheets does not indicate non-compliance; it indicates that the composite state is variable across voxel ratios and build orientations.