The multi-material configuration supplied as VisiJet RBK-RCL-L50 combines VisiJet CR-BK black rigid acrylate with VisiJet CR-CL 200 transparent rigid acrylate in a single material jetting build. The term composite in this context refers to a monolithic part containing two jetted photopolymer zones rather than a particle-filled or fiber-reinforced resin. One application in which this black/clear combination is used extensively is the production of microfluidic fluorescence manifolds for lab-on-chip and organ-on-chip test fixtures. In these builds, the CR-CL 200 regions form transparent excitation and emission windows, while the CR-BK regions create absorptive channel sidewalls and mounting structures that reduce stray-light reflection into the detector plane. The interface between the two materials is generated by adjacent jetted droplets that are cured in successive layers; it is not an adhesive bond and does not rely on solvent welding or mechanical interlocking. The main process limitation is not optical incompatibility but residual support-wax entrapment along the black/clear transition after the first oven cycle. Blind channel geometries with hydraulic diameters below 1.0 mm and aspect ratios above 4:1 are most likely to retain wax menisci. A second dwell cycle at the support material’s specified melt temperature is applied only after transmitted-light inspection confirms wax residue; the dwell time is stepped in 10-minute increments until the clear channels are free of visible films. Exceeding the upper support-removal temperature recommended by the printer manufacturer can reduce interfacial shear strength at the CR-BK/CR-CL boundary, although published data for this specific resin system is limited. Leak testing is performed with deionized water at 1.5 kPa differential pressure after the manifold has been conditioned for 48 hours at 23 °C and 50% relative humidity. The clear window is inspected for transmission loss at 488 nm and 532 nm; a transmission drop greater than 2% after fluid contact indicates swelling or surface haze. For cell-based workflows, a separate ISO 10993-5 cytotoxicity evaluation is required because the standard VisiJet CR-CL 200 and CR-BK material datasheets do not by themselves authorize biological contact. Published data for VisiJet CR-CL 200 and CR-BK under ISO 10993-12 extraction protocols is limited, so any direct sample-contact claim must be verified with the supplier’s current biocompatibility test reports.

What Limits Black/Clear Interface Integrity During Thermal Support Removal in Consumer Optical Sensor Housings?

Consumer optical sensor housing prototypes for structured-light and time-of-flight modules are built with a clear CR-CL 200 lens window and a CR-BK baffle structure in one monolithic part. The black baffle prevents cross-talk between the source and the detector, while the clear window permits calibrated optical transmission. The limiting defect in this application is not optical haze after polishing but delamination at the material transition during wax support removal. Because the black resin absorbs part of the UV curing dose, the cure depth at the CR-BK side of the interface is lower than at the clear side. This creates an interphase region with a higher fraction of low-molecular-weight acrylate species; when the part is heated to melt the support wax, the interphase expands at a different rate than the fully cured bulk, and crack initiation can occur at stress concentrations near sharp corners. Process development therefore requires control of three variables: the incident UV dose, the oven ramp rate, and the wall-thickness symmetry across the black/clear boundary. The manufacturer’s published support-removal profile for VisiJet materials is the baseline; deviations from the specified melt temperature should be justified by sectioning and fluorescent penetrant inspection. In practical builds on MultiJet Printing systems, long unsupported clear spans adjacent to black bulk sections are more prone to interfacial crack growth than discontinuous transitions with black ribs intersecting the clear lens at angles greater than 30°. Tensile samples cut from the interface in finished parts exhibit anisotropic behavior that standard homogeneous coupons do not capture. Comparative specimens are therefore evaluated according to ASTM D638-14 using Type IV geometry, with the gauge section centered on the black/clear boundary. Mechanical results are interpreted only as comparative data, not as material datasheet values.

Optical acceptance is anchored to recognized measurement methods. The transparent CR-CL 200 region is polished and measured for transmittance using ISO 13468-1 and for haze using ASTM D1003. The black CR-BK baffle is measured with a spectrophotometer equipped with an integrating sphere; a reflectance below 4% over the 400 nm to 700 nm range is a typical target for internal light traps, but the measured value depends on surface texture and residual wax. For consumer electronics fire-safety review, UL 94 HB classification of the printed resin is the minimum reference point, while electrical safety documentation is evaluated under IEC 62368-1 for audio-visual and information-technology equipment. Chemical compliance is verified through the supplier’s RoHS declaration against Directive 2011/65/EU Annex II restricted substances and REACH registration under Regulation 1907/2006. Dimensional stability after heat aging is checked by measuring the lens-mount gap before and after 72 hours at 50 °C; change in gap dimension greater than 0.10 mm on a 10 mm reference length triggers a review of part orientation and support-removal conditions.

Clear Anatomical Substrates with Black Tumor Volumes in Preoperative Planning Models

Preoperative planning models built from VisiJet CR-CL 200 and CR-BK use transparent material for surrounding soft-tissue anatomy and black material for tumor margins, vascular structures, or nerve roots. The contrast between the clear region and the black region allows surgeons to rotate the model and inspect internal spatial relationships without cutting into the anatomy. These models are non-sterile planning aids when they do not contact the patient; if they are supplied to a hospital as patient-specific anatomical replicas, their regulatory status may fall under the destination jurisdiction’s medical device framework, such as EU MDR 2017/745 or FDA 21 CFR Part 820. The build is oriented so that black tumor volumes are not enclosed by large transparent overhangs that trap support wax. After support removal, the model is inspected in transmitted light for wax veils behind the clear surfaces; residual wax appears as a low-level fluorescence or cloudy film and must be removed before dimensional verification. The clear regions are hand-polished with fine abrasive pastes to increase translucency, but local heating during polishing can introduce micro-stress at the black/clear transition. For this reason, polishing is performed in short intervals with water cooling, and the part is allowed to relax for 24 hours before dimensional measurement.

Dimensional accuracy is verified by comparing the printed tumor surface to the segmented DICOM source data using a Hausdorff distance algorithm. The clear soft-tissue envelope is checked for local thickness against the source model; measurement uncertainty is controlled according to ISO 10360-7 for coordinate measuring machine verification. If the plan is to use the model inside a sterile field, autoclave sterilization is not recommended for acrylate photopolymers because of their heat-deflection limitations. Gas plasma or vaporized hydrogen peroxide is evaluated on a sacrificial part before committing the anatomical model. Solvent cleaning is limited to 70% isopropanol or ethanol applied as a wipe; immersion beyond 30 minutes is avoided because solvent uptake can swell the clear region and alter the tumor-to-tissue boundary dimensions. Published data for the specific CR-BK/CR-CL 200 combination under biological preparation protocols is limited, so dimensional tests should be repeated after any cleaning or disinfection protocol that the receiving hospital intends to use.

VisiJet CR-CL 200 and CR-BK are also used in automotive lamp prototype housings in which a clear lens and a black bezel are printed as one component. The black bezel suppresses ghost images generated by internal reflections, while the clear lens provides direct visualization of the beam pattern from LED or laser sources. In photometric testing, the clear lens region is exposed to short-wavelength light and elevated temperature, so yellowing is a critical degradation mode. The clear section is conditioned according to ISO 4892-2 for xenon arc exposure and evaluated for yellowness index using ISO 17223; published data for VisiJet CR-CL 200 under prolonged xenon arc conditions is limited, so prototype results are interpreted as relative comparisons against the production polycarbonate or acrylic lens. The black bezel must remain dimensionally stable under bulb temperature rise; mounting bosses are reinforced with a wall thickness that avoids deflection during thermal cycling. The support wax must be completely removed from the bezel-to-lens transition because any retained wax layer changes the refractive index gradient at the interface and may appear as a bright ring in night-time beam photographs. Flatness of the clear lens is measured with an interferometer; local waviness over the aperture is kept below one-half wavelength at the test wavelength.

When a Flow Cytometry Cuvette Requires Opaque Light Stops and a Transparent Interrogation Path in One Monolithic Part

Flow cytometry cuvette prototypes are built with CR-CL 200 forming the transparent core-sheath channel walls and CR-BK forming opaque light stops and interdigital baffles around the excitation beam. The black inserts break the direct scattering path between the laser and the side-scatter detector, while the clear interrogation window allows focused beam entry. The clear window is polished and tested for transmission using ISO 13468-1 and for haze using ASTM D1003. The black light stops are evaluated with a collimated beam at 488 nm, 532 nm, and 640 nm; off-axis leakage is measured with a photodiode positioned outside the intended optical aperture. Signal-to-background improvement is highly geometry-dependent and cannot be stated as a universal value; it is determined by the distance between the black baffle tips and the laser waist, the baffle angle, and the surface texture left after support removal. Published data for VisiJet CR-CL 200 and CR-BK in flow cytometry configurations is limited. Any reported signal-to-background ratio must therefore be accompanied by the exact beam diameter, channel depth, and baffle geometry used during testing.

Chemical compatibility is critical because sheath fluid may contain phosphate-buffered saline, tris buffer, or low-percentage detergents. Acrylate photopolymers are generally not suitable for prolonged exposure to concentrated oxidizing disinfectants. If the cuvette is disinfected with sodium hypochlorite, the concentration should not exceed 1% and the contact time should be limited to a few minutes, followed by thorough rinsing with deionized water. Water absorption is measured according to ASTM D570 before the cuvette is used with aqueous buffers; dimensional swelling in the clear channel can shift the optical focus if water uptake is not quantified. The part is dried after washing with filtered compressed air at a pressure below 1.0 bar to avoid driving liquid into interfacial microvoids. If the diagnostic workflow requires high-level disinfection or repeated temperature cycles, the cuvette material must be tested under the intended cleaning chemistry; the standard VisiJet datasheets do not provide a substitute for process-specific validation.

High-Volume Camera Module Alignment Fixtures Are Built as Black Registration Grids with Clear Cover Windows

Camera module alignment fixtures combine CR-BK registration grids and CR-CL 200 cover windows in a single monolithic build, allowing simultaneous back-focal-length measurement and axial alignment during active alignment equipment trials. The black grid provides a high-contrast target for corner-detection algorithms, while the clear window protects the grid from dust and prevents mechanical drift of the target relative to the module under test. The black/clear transition is placed perpendicular to the viewing axis so that parallax at the clear-to-black edge can be measured and corrected during algorithm validation. Dimensional verification of the grid features is performed with a coordinate measuring machine using ISO 10360-7 as the measurement protocol reference. The center-to-center distance between fiducials is compared to the nominal CAD data; any deviation greater than 0.05 mm over a 20 mm span is treated as a build-accuracy failure. The clear cover is polished only on the outer surface; the inner surface remains as-printed to preserve the flatness of the black grid plane. If the outer surface is over-polished, thickness variation across the cover window changes the optical path length and shifts the measured back focal length. The support wax is removed through access holes in the black base; these holes are subsequently filled with a low-outgassing epoxy if the fixture is used in a cleanroom vacuum environment. Volatile organic compounds released from the printed resin are not quantified in the standard VisiJet datasheet; therefore cleanroom operators should obtain outgassing data from the supplier if the fixture is used near open optics.