The Stratasys Rigur Transparent PolyJet 3D Printing Polymer Combination is configured as a two-cartridge material set in which the primary model cartridge is RGD720, a rigid transparent photopolymer, and the secondary model cartridge is TangoBlack FLX973, a black elastomeric photopolymer. The configuration is intended for PolyJet systems capable of depositing at least two model materials in the same automatic build cycle. It is not a single premixed resin; the resulting part contains spatially assigned rigid transparent domains and opaque elastomeric domains. Because the final part is not homogeneous, its mechanical and optical behaviour cannot be read directly from any single-cartridge datasheet. Published data for this specific paired configuration is limited, so component-level characterisation is required before release of load-bearing or sealing applications. The difference from a homogeneous transparent material is topological: transparency exists only in RGD720-assigned volumes, while TangoBlack FLX973-assigned volumes are opaque and contribute compliance, damping, or gasket-like deformation. The descriptor Rigur also appears on separate opaque polypropylene-like PolyJet grades, and those grades should not be cross-referenced to this transparent two-cartridge combination unless explicitly confirmed in the platform material matrix.

What Limits the Interface Adhesion Between RGD720 and TangoBlack FLX973?

Interfacial adhesion in the printed part is formed by UV-initiated crosslinking at the boundary between adjacent voxels of RGD720 and TangoBlack FLX973. The process does not create a homogeneous copolymer; it produces a micro-scale compositional boundary whose strength depends on the degree of co-cure, the layer interval, and the jetting stability at the transition edge. Oxygen inhibition at the surface of a just-deposited layer can reduce conversion near the boundary, especially when the elastomeric phase is deposited over a rigid phase that has already received UV exposure. The resulting interface may behave as a discrete adhesion plane rather than a fully interpenetrating network. Because published adhesion data for this exact material pair is limited, the interface should be tested on printed witness coupons using ASTM D6862-11 for 90-degree peel resistance or ASTM D4501-01 for block shear depending on the load mode.

Production-scale failure modes observed on Connex-class systems include jetting dropout at the first voxel band following a material switch, elastomer tearing in thin TangoBlack FLX973 sections below 1 mm during support removal, and haze generation in RGD720 regions adjacent to black elastomer boundaries if support removal is incomplete. These failures are process-dependent and are not necessarily predicted by neat resin tensile values. Control of the interface therefore requires a defined print quality mode, periodic printhead purge verification, and witness coupons that replicate the same number of material transitions as the production part. Transition-zone design should also avoid large contiguous boundary surfaces without mechanical interlocking. A stepped or dovetailed boundary between the rigid and elastomer phases increases the interfacial path length and reduces peel-driven separation. Where the elastomer phase is used as a gasket, a compression stop in the rigid phase minimises over-compression and should keep the FLX973 phase within its linear viscoelastic region. The vendor does not publish a single allowable strain for the combined configuration, so deflection limits should be derived from part-level compression set testing per ASTM D395-18 Method B.

Processing Window and Equipment Compatibility Boundaries

This material set is limited to PolyJet platforms that maintain separate heated bays for the primary and secondary cartridges. The RGD720 resin and TangoBlack FLX973 resin are jetted at different printhead temperature setpoints because their viscosity ranges differ. Cold-start jetting below the vendor-specified temperature can produce missing jets and local delamination at material boundaries. Cartridges should be conditioned to a handling range of 18–25 °C before installation; resin temperature inside the printhead is maintained by the machine control loop, not by the ambient build chamber. Build-chamber humidity excursions above 60 % relative humidity can trigger condensation on the printhead or part surface and should be avoided unless the platform is equipped with active drying.

Compatibility with J8-series platforms is not automatic. The J8-series closed material architecture may restrict older resins such as RGD720 or TangoBlack FLX973 to approved combinations. The current Stratasys material compatibility matrix is the controlling document; a cartridge physically loading into a bay does not confirm printability. On Connex-class systems, the combination can be assigned to separate model material channels, but the target layer interval must support both resins in the same build. High-quality glossy modes often use a thinner layer interval, typically in the 16–30 μm range depending on platform, while high-speed modes increase layer interval and may alter interfacial definition and elastomer edge fidelity. Parts with more than 50 material transitions per layer should be evaluated on a first witness coupon for missing voxels or streaks at transition bands. If missing jets are found, head cleaning and re-verification according to the equipment manual are required before production builds begin.

Solvent and chemical boundaries are significant for mixed rigid-elastomer parts. The RGD720 phase is susceptible to crazing when exposed to strong ketones or chlorinated solvents, and the TangoBlack FLX973 phase can swell or undergo colorant migration if exposed to aggressive solvents. Isopropyl alcohol should not be used for prolonged immersion; water-jet removal of support or a controlled soluble-support bath is preferred. Alkaline soluble-support baths should be validated per ASTM D543-21 before use on production parts because dimensional change of the elastomer phase may not be captured by visual inspection alone.

Table 1 lists representative neat resin values reported for the individual constituents in public Stratasys technical data. The values are provided for design comparison and do not represent tested properties of the combined Rigur Transparent configuration.

Where the final part must combine optical transmission with elastomeric sealing, two property sets must be measured separately. The RGD720 phase should be assessed for luminous transmittance and haze according to ASTM D1003-21 at the production wall thickness and after the production support removal process. The TangoBlack FLX973 phase should be assessed for compression set according to ASTM D395-18 Method B at the maximum service temperature and for tear resistance according to ASTM D624-00. Published data for this specific Rigur Transparent pairing under continuous sealing load is limited; vendor neat-resin data must not replace component-level leak testing. In practice, low-pressure fluidic housings or protective covers should be leak-tested at 1.5× the maximum working pressure for a defined dwell period of at least 30 min, with a pressure-decay limit set from the application tolerance.

One process constraint observed in multi-material builds is that the black elastomer phase can retain water after support removal or leak testing. Dimensional metrology on sealing lips should be conducted only after mass stabilisation according to ISO 62:2008 or after a controlled drying cycle at 25 °C and 50 % relative humidity until consecutive mass measurements differ by less than 0.1 %. If optical inspection is performed immediately after support removal without drying, residual moisture at the interface can create false haze readings because water films scatter light at the boundary.

If Colour Contrast Is Required Without Compromising Rigid Transparency

The pairing is selected when the CAD model includes both transparent rigid volumes and black elastomeric volumes. The black pigment in TangoBlack FLX973 limits optical transmission to near zero in its assigned voxels; therefore the material cannot produce a grey translucent rubber. If a translucent or light-coloured elastomer is required, alternative secondary resins such as TangoPlus FLX930 or Agilus30 Clear FLX935 should be considered, but their mechanical properties and cartridge compatibility differ. The RGD720 primary phase is a rigid transparent material, but its clarity is influenced by layer interval, support residue, and post-processing. Transmission and haze should not be specified from as-used values if the part is not dried and cleaned; the relevant test method is ASTM D1003-21.

Compared with a single-cartridge transparent material such as VeroClear RGD810 or VeroUltraClear RGD820, this combination adds a secondary elastomer channel rather than increasing optical clarity. The rigid RGD720 phase is not equivalent to polished PMMA or glass; it is a photopolymer with measurable haze and layer-line influence. The primary reason to select this set is the ability to produce a transparent load-bearing envelope and a black flexible element in the same automated build without insert moulding or adhesive bonding. If the product does not require the secondary elastomer, a single transparent rigid resin on the same platform may reduce process complexity and eliminate material-switch boundary risk.

Support Removal, Solvent Exposure, and Post-Processing Distortions

Support removal on mixed rigid-elastomer builds is more restrictive than on rigid-only PolyJet parts. Water-jet removal can delaminate the interface if the jet is directed along the boundary at close range. The black FLX973 phase is soft and can be damaged if local section thickness is below 2 mm; support removal in those areas should be performed at reduced pressure or with hand tooling. If soluble support chemistry is required, the bath concentration and temperature must be controlled to the support material datasheet, and the FLX973 phase should be checked for swelling, colorant bleed, or mass change according to ISO 62:2008. The rigid RGD720 phase can be polished only on the surface; polishing across the interface may embed black elastomer debris into the transparent domain and is not recoverable without material removal.

Coating or painting the elastomer phase is not generally recommended because the low surface energy of the FLX973 phase can produce poor adhesion. If a coating is unavoidable, cross-cut adhesion should be tested per ASTM D3359-17 after full curing. For bonding to metal or glass inserts, adhesive compatibility with both RGD720 and TangoBlack FLX973 should be evaluated, and the bond line should be located away from the material boundary. The operational limits are therefore a combination of resin chemistry, geometrical interface design, and post-processing sequence, not a single mechanical property.