On a ProJet MJP 2500/3600 platform, VisiJet RCL-EBK-A50 co-jets a rigid transparent phase and a Shore A 50 elastomeric phase in a single build. The A50 designation refers to a nominal elastomer hardness of 50 Shore A under ASTM D2240. The rigid phase is assigned to lens covers, snap-fit frames, and optical windows; the elastomeric phase is assigned to strap flexures, lug tabs, and button diaphragms. For a wearable device, the primary process conflict is the z-axis anisotropy of the elastomer versus the optical flatness of the clear CR-CL 200 phase. A window built perpendicular to the XY plane exposes 32 µm layer lines; therefore, optical-grade surfaces are oriented upward and polished to 0.8–1.6 µm Ra before transmission measurement per ASTM D1003. The CE-BK strap section is oriented with its flex axis in the XY plane to keep cyclic bending within the polymer network of a single layer and to reduce interlaminar shear. Elongation at break of the elastomeric phase is checked on ASTM D412 die C specimens. Interfacial tensile strength at the rigid-elastomer junction is checked on ASTM D638 Type V bars printed in the same orientation as the production part; published data for this specific paired configuration is limited, so lot-specific values are required. MJP support wax retained in undercut strap retainers can alter pull-out force during repeated flex testing, and complete removal in a VisiJet S300 support removal oven is therefore mandatory. The clear phase is not polished with ketone-based solvents because microcrazing can develop at snap-fit stress concentrations after immersion per ASTM D543. For short-term dermal contact prototypes, ISO 10993-5 cytotoxicity data from the current material documentation must be reviewed because this photopolymer may not carry a full ISO 10993-1 production certification.

What Limits Build Orientation When Mating CR-CL 200 Windows with CE-BK Living Hinges?

Medical devices and diagnostic cassettes often need a transparent viewing window and a soft sealing lip in the same disposable cartridge. The rigid CR-CL 200 phase is assigned to the window, luer-compatible adapters, and pressure-sensitive mounting bosses; the CE-BK phase is assigned to the compression seal, valve diaphragm, and thumb-grip regions. The build orientation is constrained by two competing requirements: the clear window must be printed flat to preserve optical clarity, while the elastomeric hinge or seal lip must be printed so that cyclic bending or compression does not propagate between layer boundaries. On a ProJet MJP 3600 with a 32 µm slice interval, the interlayer bond in CE-BK is the weakest mechanical plane. A hinge flexed across the z-axis can show interlaminar cracks after repeated cyclic loading; a hinge flexed in the XY plane is more stable because the polymer network is continuous within the build layer. Optical haze in CR-CL 200 regions is influenced by support-wax contact and should be evaluated per ASTM D1003 after the supplier-recommended support removal protocol. For fluid-path cartridges, the CE-BK phase is evaluated for swelling by ASTM D543 immersion in the target reagent for 24 h at 23°C; the clear phase is evaluated for environmental stress cracking at the same time. A valve diaphragm printed as a 0.8 mm thick CE-BK disc must achieve closure against 0.2 bar back pressure without visible deformation of the clear CR-CL 200 seat; the leak rate is recorded with a calibrated pressure-decay tester. The material set has no true hardness gradient between the rigid and elastomeric phases; the interface is a discrete material boundary defined by the slice file. Therefore, the transition between a rigid CR-CL 200 boss and a soft CE-BK seal should be reinforced with a mechanical interlock, such as a dovetail or through hole, to prevent peel from starting at the boundary. When thermal aging is required, dimensional and hardness drift are checked per ASTM D2240 and the relevant dimensional standard; published data for this specific paired configuration is limited. Applications include disposable microfluidic prototypes, point-of-care diagnostic housings, and ergonomic handpiece overmolds that must be visibly inspected for seal seating.

When printed for automotive interior controls, the composite substitutes for two-shot ABS/TPV concepts in early cockpit verification. The CE-BK phase forms the soft button cap, knob bezel, and switch surround; the CR-CL 200 phase forms the clear icon lens and snap features. Build trays should orient the button cap face upward so that the top layer is free of support-wax contact; this preserves the matte-to-gloss distinction required by the design studio, checked with a 60° glossmeter. The clear icon window is polished to 0.8–1.6 µm Ra before pad printing; the elastomeric surface is cleaned with isopropanol only, because aromatic solvent wipes increase the surface tack of CE-BK and reduce ink adhesion. For backlit assemblies, the clear CR-CL 200 phase is measured by ASTM D1003 to confirm light transmission after xenon arc exposure per ISO 4892-2 if prototype durability is required. Automotive interior VOC emissions are assessed under VDA 278; because uncured acrylate residues may be present, the parts are conditioned according to the VDA 278 sample preparation protocol before placement in the thermal desorption system. The Shore A hardness of the CE-BK phase is checked after 24 h ambient conditioning with ASTM D2240; any drift must be referenced in the profile tolerance plan and verified lot by lot. Push-force measurements on a constant-rate extension tester show that build orientation affects actuation force because of anisotropic column stiffness in the digital elastomer, so top-oriented button caps are preferred for consistency. Squeak-and-rattle screening on a shaker table using the OEM interior profile, such as VW 9648, should be restricted to short cycles because CE-BK does not carry a production-grade long-term heat aging rating. The material is not rated for 150°C continuous use and does not replace UL 94 V-0 compliant production resins; application scope is limited to cockpit mockups, ergonomic validation, and pre-production test cells where final material DV/PV is run on production polymers later.

Viscous Resin Management and Cartridge Temperature Windows on ProJet MJP 3600 Series

In industrial fluid handling and soft-touch overmold applications, VisiJet RCL-EBK-A50 is used for manifold covers, gasket ribs, and inspection windows that must be built as one piece. The MJP head operates at low resin viscosity; therefore, the cartridge and chamber temperature must remain inside the supplier jetting window. A temperature drift outside the fixed window can cause CE-BK viscosity rise, transient starve-out at the piezoelectric nozzle array, and missing jetting on initial layers. Excessive temperature can increase pinhole formation in flat transparent CR-CL 200 sections. The thermal-jetting window is therefore a more critical parameter than for single-material MJP builds.

After the build, the part is placed in a VisiJet S300 support removal oven. The elastomeric CE-BK phase should not be exposed to oven temperatures above the supplier default setpoint for prolonged periods because the digital elastomer softens and the gasket lip can creep out of flatness. If the support removal oven is equipped with a programmable ramp, a two-stage cycle is used: a wax-melting stage at supplier default, followed by a cooled drain stage. The CR-CL 200 viewing window is then polished with alumina slurry on a low-speed rotary polisher; water is used as the carrier because solvent-based polishing compounds can craze the photopolymer. Gasket ribs are printed at 0.6–0.8 mm width and 0.4–0.6 mm height. The flange is rigid CR-CL 200 with a 2.0 mm minimum wall thickness around the viewport. The seal is compressed between 15% and 25% of rib height using a torque-limited fixture; the leak rate is recorded on a pressure-decay instrument. Fluid compatibility for each application must be evaluated by ASTM D543 immersion. Acetone, MEK, and chlorinated solvents are generally not acceptable for the CE-BK phase; short exposures can produce swelling and gasket extrusion. The CR-CL 200 phase should not be exposed to high-pH aqueous solutions without lot-specific testing. Published data for the RCL-EBK-A50 paired configuration is limited, so compatibility screening is mandatory before use in production-like fluid cells.

When a Shore A 50 Digital Elastomer Replaces Cast Polyurethane in Footwear Prototypes

Footwear midsole lattice structures and strap cushions are built with the CE-BK phase, while the CR-CL 200 phase provides transparent toe-box windows or arch support plates for fit trials. The CE-BK phase is not closed-cell foam; its Poisson ratio and volume compressibility differ from an EVA or polyurethane foam. Therefore, the digital part is used for geometry, assembly, and flex test correlation, not for final cushioning-force prediction. A gyroid lattice with 1.2 mm strut thickness and 20–30% relative density is assigned to CE-BK to mimic the visual and flexural response of a midsole; the lattice cell size is set at 4–6 mm. The CR-CL 200 phase is printed as a 2 mm plate in the arch or shank region. Density is checked by ASTM D792 on solid discs; the Shore A hardness of the CE-BK phase is recorded after 24 h conditioning per ASTM D2240. Dynamic mechanical analysis of the elastomeric phase is performed under ASTM D4065 at 1 Hz and a temperature sweep from -20°C to 60°C; the tan δ peak location should be referenced to the development specification before committing to a sole flex test. SATRA TM92 or a simplified 90° repeated flex test is used to evaluate crack growth in the lattice nodes; the z-axis crack growth should be compared to the XY-axis because interlayer adhesion dominates failure. Footwear prototypes are therefore built with the shoe longitudinal axis parallel to the XY plane. The transparent toe box is polished to remove support artifacts; haze is checked by ASTM D1003 and surface roughness by ISO 4287. If the part is used for fit trials, the CE-BK surface is coated with a water-based skin-safe release because photopolymer residues should not contact skin for prolonged periods unless ISO 10993-5 and ISO 10993-10 data are available. Operational boundaries include low-temperature brittle behavior below 0°C, where CE-BK may exhibit reduced elongation and crack propagation in the heel lattice, so cold-conditioned wear trials require pre-test validation. Published data for RCL-EBK-A50 in footwear-specific flex fatigue is limited; prototype results should be used only as build-orientation and geometry screening tools.

Vibration isolation and acoustic damping components make use of the CE-BK phase as a lossy elastomer and the CR-CL 200 phase as a rigid light-transmitting bracket or housing. In a drone camera mount, the composite can replace a two-part machined isolator by jetting four CE-BK spherical grommets of 12 mm diameter between a CR-CL 200 camera carrier and a rigid frame. Transmissibility is measured on an electrodynamic shaker at 0.5 g input from 10 Hz to 500 Hz; the natural frequency of the isolated assembly should be tuned below 30 Hz. Damping is evaluated by ASTM D4065 in a frequency sweep at 25°C; the CE-BK photopolymer generally exhibits lower loss factor than cast silicone or polyurethane, so the designer should not assign a high-damping requirement without lot-specific data. The clear CR-CL 200 phase is used for an alignment window; optical transmission is measured by ASTM D1003 after polishing, and the window is not load-bearing in vibration. Threaded inserts in CR-CL 200 are limited to supplier-recommended screw torque; cold pressing is preferred because excessive thermal input can soften the photopolymer. For acoustic applications, such as speaker gasket prototypes and microphone boot seals, the CE-BK phase is printed as a 0.8 mm continuous bead. The acoustic seal is compressed between the transducer and the rigid CR-CL 200 faceplate; the leak rate is checked by pressure decay and the acoustic response is measured by impedance tube per ISO 10534-2. This application is limited to low-temperature, short-duration validation because the photopolymer does not have the long-term heat and UV aging stability of engineering silicone or EPDM. For any production-intent assembly, the material is only a surrogate for mechanical fit and seal-line geometry; qualification must be repeated on the production elastomer according to OEM material specifications. Published data for the RCL-EBK-A50 composite in acoustic and vibration environments is limited, and all performance claims must be traced to lot-specific tests rather than to generic photopolymer literature.