3D Systems VisiJet RWT-ENT-D75 Multi-Material Composite is a two-feedstock digital photopolymer formulation for MultiJet Printing platforms that maintain separate heated reservoirs for VisiJet CR-WT 200 and VisiJet CE-NT. The composite is generated in the build envelope by piezoelectric inkjet deposition of the two base resins; it is not a pre-compounded resin. The product designation RWT-ENT-D75 denotes a rigid-white-translucent/elastomer-natural-translucent digital blend with a nominal hardness of 75 on the Shore D scale. The rigid parent resin contributes crosslink density, indentation resistance, and dimensional stiffness; the elastomeric parent resin contributes segmental mobility, recovery after strain, and visible translucency. Published manufacturer process documentation describes the composite as part of a durometer-designated family whose mechanical properties are controlled by the digital mixing ratio. Independent third-party datasets for the D75 grade are more limited than those for single-component MJP photopolymers; therefore, release testing should be performed on the target machine using coupons conditioned to ASTM D618-21 or ISO 291:2008.

What process parameters control the CR-WT 200/CE-NT transition zone and Shore D 75 response?

The local ratio of the two base resins at the build plane is the primary variable determining cured modulus, elongation at break, and Shore D indentation. The MJP control algorithm assigns printhead pixel duty cycles so that each voxel receives either pure VisiJet CR-WT 200, pure VisiJet CE-NT, or a digitally mixed blend. The printed part is exposed to UV radiation from the traversing carriage; the curing threshold for the mixed voxel may differ from that of the parent resins. If lamp output or cure time is set below the manufacturer’s minimum value, surface tack and reduced crosslinking can lower hardness by several Shore D points. Overexposure can embrittle the elastomeric phase and reduce the elongation that would otherwise be reported under ASTM D638-14. For build documentation, the operator should record build-material temperature, printhead voltage, planarizer height, and layer thickness from the machine log. On the ProJet MJP 5000 series, the software maintains those parameters within a qualified range; however, lot-to-lot variation in uncured resin can shift the required temperature setpoint by 1 to 3 °C, which is typical for low-viscosity acrylate inkjet resins. That shift is not unique to RWT-ENT-D75, but it has greater consequence at the mixed-material interface because under-cured transition voxels can delaminate during support removal or post-processing.

Support removal for multi-material MJP builds introduces a thermal exposure limit. The wax or soluble support material used with the paired-resin system is liquefied or dissolved after the build. The heat deflection temperature of the composite is evaluated under ASTM D648-16 at 0.455 MPa, and the applied support removal temperature should remain below the onset of creep in the translucent phase. Because CE-NT-rich regions have a lower continuous-use temperature than CR-WT 200-rich regions, a build with thick elastomeric zones may require lower defatting temperatures or longer dwell times. Published data for this specific configuration is limited; qualification should include deflection measurements on 5-mm-thick specimens taken from the thickest CE-NT-dominant area. If parts are cleaned in a solvent bath, the solvent class must be selected for compatibility with cured acrylate networks. Strong basic solutions and amine-based additives are excluded because they can initiate additional surface crosslinking or localized swelling. The uncured resins in the printhead path are sensitive to moisture and should not be combined with an alcohol-based flush unless the equipment manufacturer explicitly approves the fluid for the specific printhead assembly.

Shelf-life controls, moisture conditioning, and dimensional verification standards for multi-durometer builds

Conditioning protocols for the composite are defined by ASTM D618-21 or ISO 291:2008 at 23 ± 2 °C and 50 ± 5 % relative humidity. After support removal and drying, printed parts are rested under those conditions before tensile, flexural, hardness, or dimensional measurements. Dimensional verification is performed with a calibrated coordinate measuring machine or contact profilometer, with particular attention to the interface between rigid and elastomeric zones. Differential volumetric shrinkage during UV cure and thermal cycling produces residual stress at that interface; resultant warpage is usually higher than in single-material CR-WT 200 or CE-NT builds. Tensile test specimens should be sampled in both X-Y and Z orientations because inkjet printing produces anisotropic mechanical properties. ASTM D638-14 Type IV specimens and ASTM D790-17 flexural bars provide the most reproducible comparisons for small production platforms. The Type D durometer value of 75 is determined under ASTM D2240-15(2021) on a printed plaque or stacked specimen with a minimum thickness that prevents backing effects. Digital composites of this class generally exhibit lower tear strength than cast elastomers of identical Shore D hardness; therefore, if a design includes live hinges or high-strain flexural zones, the component should be tested to ASTM D624-00(2020) for tear resistance or ASTM D7774-17 for flexural fatigue under the expected number of cycles. The absence of a molded compound interface does not eliminate notch sensitivity in the gradient zone.

The RWT-ENT-D75 composite is typically specified when a production prototype requires a white translucent rigid frame with integrated elastomeric sealing ribs, snap features, or impact-absorbing regions that cannot be produced in a single-pass rigid-only photopolymer. In comparison with VisiJet M2R-WT, the composite has lower bulk stiffness but eliminates secondary bonding of a separate elastomer. In comparison with a pure CE-NT part, the composite offers higher resistance to indentation, lower surface tack, and improved dimensional stability under load. Unlike mechanically assembled multi-material parts, the digital composite does not contain a chemical adhesive layer at the rigid-elastomer interface; instead, the transition is produced by changing the ratio of the two feedstock resins voxel by voxel. That transition zone should be treated as a non-isotropic region for finite-element model calibration rather than as an infinitely thin bond line. Published application examples for the material class include soft-touch industrial tooling, overmolded electronics prototypes, fluidic manifolds, and anatomical models for procedural simulation; however, independent long-term aging or fatigue data for the D75 grade are not widely available. Where the component contacts skin or mucosal surfaces, the manufacturer’s compliance documentation should be reviewed against ISO 10993-1:2018 and relevant regional chemical safety regulations such as REACH and RoHS.

When RWT-ENT-D75 is evaluated as a replacement for cast polyurethane or rigid injection-molded assemblies

The comparison is not governed solely by Shore D hardness. A cast polyurethane of Shore D 75 generally has a different tensile stress-strain curve, tear propagation resistance, and dynamic mechanical response than an acrylate photopolymer composite of the same nominal durometer. Designers should compare tensile modulus, elongation at break, notched impact strength, and compression set under ASTM D395-18 before substituting the printed material into an existing molded-part drawing. The digital composite also has anisotropic properties that depend on build orientation, voxel size, and post-processing. In contrast to injection molding, the MJP process does not apply high shear to the melt; molecular orientation arises from droplet spreading and UV cure, not from cavity filling. This difference often results in lower elongation in the Z axis. For functional assemblies, the interface between the two base resins must be tested under the service environment, including thermal cycling from -20 °C to 60 °C if the part will experience that range; published data for this specific configuration is limited at the extremes. If the application requires a defined coefficient of linear thermal expansion, ASTM E831-19 can provide direction, but the result may vary between rigid and elastomeric zones. A rigid-only photopolymer datasheet should not be applied across the entire composite volume.

Operational boundaries for the composite include moisture sensitivity, solvent incompatibility, and finite dark storage stability. Uncured containers should be stored in sealed, opaque vessels at the temperature range specified by the manufacturer. At relative humidity above 60 %, the elastomeric phase may absorb sufficient atmospheric moisture to alter dimensional stability and surface energy; pre-drying at 40 °C for 4 h may be required before secondary bonding or coating, but the exact cycle must not exceed the manufacturer’s maximum drying temperature to avoid distortion. Contact with strong oxidizing acids, ketone solvents, or prolonged immersion in isopropyl alcohol can soften the CE-NT-rich regions. Surface treatments such as plasma or corona increase wettability but may create visible haze on the translucent phase; if optical clarity is critical, these treatments should be restricted to the rigid white zones. The product is not classified as a finished biocompatible material solely because it is printed in a medical-adjacent multi-material platform; chemical safety documents must be obtained directly from 3D Systems for the intended regulatory path. Waste support material and uncured process waste must be handled according to local regulations for photopolymer process waste and should not be discharged into sanitary drains.