The VisiJet RBK-EBK-D65 Multi-Material Composite set is a dual-resin architecture based on VisiJet CR-BK and VisiJet CE-BK. The system is not a bulk blend. The two materials are jetted as discrete voxels within a single build and UV-cured layer by layer. The D65 designation describes the Shore D hardness of the composite interface after full post-cure. The rigid CR-BK phase provides load-bearing surfaces, threaded bosses, snap-fit features, and dimensional stability. The elastomeric CE-BK phase provides sealing compression, impact attenuation, hinge flexure, and friction-grip surfaces. In production qualification, the mechanical boundary between the two phases is the controlling failure site. Interfacial peel strength, compression set, and solvent carryover from support removal determine whether a downstream application is viable. The applications below are limited to sectors where rigid-elastic integrated parts replace multi-step assembly or overmoulded inserts.

What Limits Shore D65 Overmoulded Seal Retention in Handheld Diagnostic Devices?

Handheld diagnostic housings require a rigid shell for PCB mounting, battery retention, and drop protection. The same housing requires a compressible seal around the sample port or battery door. In a VisiJet RBK-EBK-D65 build, the CR-BK shell is printed with a CE-BK gasket fused at the boundary. The rigid-to-elastomer volume ratio in the sealing zone is normally set between 60% and 80% rigid shell and 20% to 40% elastomer by volume. The exact ratio is defined by the compression travel required from the door latching mechanism. The process window is controlled in 3D Sprint at the voxel level. The interface is not a glued bond. It is a UV-co-cured network of interpenetrating photopolymer chains. Retention of the seal under repeated door closure is evaluated by ASTM D1876 peel adhesion on printed witness plaques and by compression set testing according to ASTM D395-18 Method B. Compliance for skin-contact and sample-carrying housings cannot be assumed from the material label alone. Each final washed part must be tested to ISO 10993-5:2009 for cytotoxicity, ISO 10993-10:2021 for irritation and delayed-type hypersensitivity, and ISO 10993-1:2018 for risk-based biological evaluation. The finished diagnostic housing is a single-piece part with an elastomeric battery-door gasket, sample-port O-ring, and rigid latch bosses. The support wax bakeout step must be validated because residual paraffin trapped in the sealing interface lowers peel strength below the threshold required for ingress protection.

Automotive interior switch packs with metal-glass contacts demand a rigid bezel material that does not creep under ultrasonic welding of the rear switch body. The CR-BK phase in the printed bezel carries weld bosses and snap features. CE-BK is assigned only to the underside gasket and button return elements. In this configuration, the volume fraction of CE-BK is kept below 30% of the total part volume to prevent loss of ultrasonic energy transmission at the weld line. The process sequence includes jetting of both resins in one build, followed by wax removal and UV post-cure. The completed switch pack bezel integrates a dust-tight elastomer lip, a rigid snap grid, and opaque black visual surfaces. Compliance is evaluated against ISO 16750-4:2010 thermal cycling and IEC 60529:2013 IP5X dust ingress. The CR-BK-to-CE-BK boundary is inspected by cross-section microscopy at 20× magnification after thermal cycling from -40°C to 85°C. Interfacial voiding above 5% of the seal cross-section is rejectable. Published data for this specific composite configuration in automotive interior lifecycle testing is limited. Qualification should include at least three build jobs to capture batch-to-batch variation.

When the Rigid Frame and Compression Gasket Are Printed in One Uninterrupted Build

When the rigid frame and compression gasket are printed in one uninterrupted build, the design eliminates a secondary gasket insertion station. The rigid-to-elastomer ratio is not uniform across the part. In the gasket trough, CE-BK is assigned as the continuous top layer at 0.8 mm to 1.2 mm thickness over a CR-BK base. Along the outer frame walls, CR-BK constitutes 100% of the cross-section for screw-hoop strength. The critical process constraint is the wash solvent temperature. If the solvent bath is held above the CE-BK heat deflection temperature, the gasket swells and the interfacial zone loses dimensional alignment. A lower-temperature rinse with the manufacturer-specified support removal solvent is used, followed by forced-air drying before the UV post-cure. The finished product is an electrical enclosure faceplate with an integral IP67-style compression seal, threaded inserts, and rigid standoffs. Compliance verification includes IEC 60529:2013 IPX7 immersion and ASTM D412-16 tensile tear testing of the elastomer phase. Interfacial adhesion is checked by ASTM D1876 after 7 days of humidity ageing at 40°C and 93% RH. The part is not suitable for continuous immersion if the elastomer phase shows compression set above 25% under ASTM D395-18 Method B. Published data for this specific configuration is limited. Sealing performance should therefore be validated on production-representative geometries.

End-of-arm tooling on packaging lines introduces repeated compressive impact at cycle rates up to 30 cycles/min. A CR-BK gripper frame provides pneumatic cylinder mounting bosses and dowel-aligned jaw seats. CE-BK contact pads are printed directly onto the jaw surfaces to clamp ampules, vials, or small electronic housings without marring. The architecture uses a 50/50 rigid-to-elastomer volume ratio in the jaw subassembly. CR-BK forms a continuous back plate. CE-BK forms protruding conical pads. The local hardness must remain within the D65 composite tolerance. Hardness is measured per ASTM D2240-15 Type D. The process demands that the elastomer pad undersides be free of support wax. Wax residue reduces friction against the workpiece and creates a shear plane at the interface. Operators validate pad adhesion by applying the ASTM D429 Method B adhesion-to-substrate test to printed witness jaws from the same build. The terminal product is a pick-and-place end effector that replaces discrete rubber-bonded jaws. Compliance for machinery safety is evaluated under ISO 13849-1:2023 for the pneumatic circuit. The printed gripper must meet ISO 604:2002 compressive strength at the rated cylinder force. Published data for this specific composite in packaging-line end effectors is limited. Batch-lot testing of pad hardness according to ASTM D2240-15 is recommended for each build.

Thermal Cycling Shifts Interfacial Crosslink Density in Orthotic Shell Living Hinges

Thermal cycling shifts interfacial crosslink density in orthotic shell living hinges. The CR-BK phase provides a load-bearing heel counter and arch support. The CE-BK phase forms a dorsal strap-fold hinge and padded liner contact points. The build ratio varies from 85/15 rigid-to-elastomeric volume at the shell body to 40/60 at the hinge zone. The hinge zone is printed as a gradient lattice to reduce stress concentration at the transition. Process control focuses on the UV post-cure uniformity. Undercured CE-BK in the hinge fold loses flexural fatigue resistance and develops surface tack after exposure to skin oils. The complete orthotic shell must be processed through the manufacturer-specified wax removal and post-cure stations without warpage. Terminal parts are worn against the skin and require biological evaluation according to ISO 10993-10:2021 and ISO 10993-5:2009. Mechanical validation uses ASTM D638-14 for CR-BK tensile strength and ASTM D412-16 for CE-BK tear strength. The living hinge is cycled under ASTM F1976-13 flex fatigue at -10°C and 40°C. Published data for this specific composite in orthotic living hinges is limited. Each geometry should be pilot-tested across at least two build orientations because the hinge flexion direction relative to the print layers controls crack propagation.

Because a rigid cable pass-through must maintain ingress protection while the elastomer absorbs cable movement, a CR-BK gland plate is printed with a CE-BK cable grommet as a single solid. The grommet aperture receives a convoluted CE-BK bellows. The CR-BK plate holds mounting holes and a sealing lip. The elastomer-to-rigid ratio in the pass-through body is 25/75 by volume. The sealing zone uses interpenetrating voxel bands rather than a sharp plane. Process priority is given to the interior wash of the convoluted bellows. If the support wax is not fully removed from the convolutions, the bellows becomes brittle after post-cure and cracks during cable articulation. The finished product is an electrical cabinet cable entry plate with integral strain relief, replacing two-component grommet assemblies. Compliance is checked under IEC 60529:2013 IP66 dust and water-jet exposure. Tear resistance is measured per ASTM D624-00 Die C. Long-term exposure to UV and ozone is outside the published data set for this composite. Outdoor cabinets therefore require an additional validation programme to ISO 4892-3:2024 accelerated weathering. The part must be tested for flammability under UL 94 HB on the final washed and post-cured wall thickness if used inside electrical enclosures.