VisiJet RBK-EBK-D70 is a voxel-controlled multi-material build composite produced from VisiJet CR-BK rigid black and VisiJet CE-BK elastomeric black. The D70 suffix identifies the nominal 70 Shore A target for elastomer-rich zones, not a bulk weight ratio. Because composition is assigned locally in the MJP print file, the hard/soft fraction changes from layer to layer and within a single layer. Datasheet values for pure CR-BK and pure CE-BK do not transfer directly to the digital composite. Each downstream application must be validated on printed coupons under its own service test standard. This requirement is particularly acute at hard/soft transition zones, where tear strength varies with gradient width, layer orientation and support removal history. The following applications use the composite only for prototype, planning and short-run production parts; no long-term load-bearing property is implied without independent verification.

Low-volume electric vehicle charge-port cable glands, firewall grommets and low-voltage harness sleeves are printed as single-build multi-material replacements for overmoulded PA66/TPE assemblies. The CR-BK rigid phase forms the clip tower, shroud and route-retention collar. The CE-BK-rich D70 phase forms the wire-entry bellows and circumferential sealing lip. The transition between the rigid flange and the elastomer bellows is defined as a graded zone of 10–12 build layers in the MJP file; this zone must not be reduced below 6 layers on production-scale MJP systems because interface peeling has been observed at shorter gradients. On a ProJet MJP 5600-class platform, the layer thickness is 0.032 mm in HD mode. Support removal is performed in a heated oil bath following the cartridge supplier protocol. The elastomer lip is printed with a free height of at least 1.2 mm and a root radius of 0.8 mm. Tear strength is evaluated per ISO 34-1:2015 method B and compression set per ISO 815-1:2014 under 25% strain for 22 h at 70 °C. If the gland must provide an IP67 seal, the full assembly is tested per IEC 60529:2013. Terminal parts include EV charge-port cable glands, firewall pass-through grommets and low-voltage harness sleeves. Flammability classification of the rigid phase is verified per IEC 60695-11-10:2013 using 20 mm vertical burn specimens. Published data for this specific RBK-EBK-D70 digital composite under automotive thermal cycling is limited; cycle validation per ISO 16750-4:2010 is the responsibility of the end-user. The elastomer phase should not be exposed to aromatic hydrocarbon fluids without qualification because swelling and loss of lip seating force may occur; fluid compatibility is tested per ISO 1817:2022 before production release.

When Overmoulded Power Tool Grips Replace Two-Shot Injection Moulding

Short-run handheld power tool grips are built with a CR-BK rigid shell and a CE-BK-rich D70 overmould zone in one MJP build. The D70 recipe places elastomer-rich voxels only on the palm contact surface and the trigger finger pad. The structural shell around motor housing bosses remains CR-BK-rich. A nominal elastomer-rich thickness of 2.5–3.0 mm is used at the grip surface, decreasing to 0 mm at the battery latch and trigger pivot. The hard/soft interface is oriented at 15°–30° from the build-plane Z axis for parts that will be drop tested. Tensile modulus of the rigid phase is measured per ISO 527-2:2012 on type 1A specimens; Shore A of the elastomer-rich zone is checked per ISO 7619-1:2010 on 6 mm coupons. Tear strength at the interface is assessed with a trouser tear specimen aligned to the hard/soft boundary and loaded under a 500 N load cell. Production-scale MJP builds have shown interface peeling when the transition zone is compressed into fewer than 6 layers; increasing the gradient to 10–12 layers reduces notch-sensitive failure after drop loading. Drop testing is performed per IEC 60745-1 clause 20 for handheld tools. Terminal parts include angle-grinder soft grips, hammer drill handle covers and industrial sander housings. RoHS compliance is documented from material certificates under 2011/65/EU. REACH SVHC statements are required for EU market entry. Pure CE-BK is not a direct substitute for the D70 composite in high-applied-force zones because the unreinforced elastomer phase lacks creep resistance; creep is evaluated per ISO 899-1:2017 if sustained grip force is expected. The D70 composite is not recommended for continuous service above 70 °C without validation because hardness drift above 75 Shore A has been observed in accelerated ageing tests.

Drop-protected housings for handheld spectrometers use a rigid CR-BK frame and a CE-BK-rich D70 corner bumper. The D70 recipe confines elastomer-rich material to the four corner zones and the top edge rail, leaving the display window seat and mounting bosses in CR-BK-rich composition. Build orientation is set so the hard/soft interface plane is not parallel to the drop-load direction; a tilt of 15°–30° from the Z axis is retained. Free-fall testing is performed per IEC 60068-2-31:2008 from 1.0 m onto concrete. After 10 drops, the corner bumper is inspected for tear propagation; tear length is measured per ISO 34-1:2015. Threaded brass inserts are placed into the rigid CR-BK bosses, and torque retention is checked at 1.2 N·m for M3 inserts per ISO 898-1. Terminal parts include handheld Raman spectrometer housings, portable industrial code reader bodies and field communicator enclosures. RoHS documentation follows 2011/65/EU. For electrical appliance safety, the rigid phase must be proved to meet IEC 62368-1:2018 enclosure requirements for the intended end product. The D70 composite is not a substitute for a fully elastomeric sleeve when corner impact energy exceeds the tear resistance of the 70 Shore A phase; in such cases the bumper thickness is increased by 1.5 mm increments and retested. No UV weathering claim is made for the black phases; outdoor use requires testing per ISO 4892-2:2013 method A.

Pneumatic Valve Prototype Seats with CE-BK-Rich Sealing Ribs

Prototype pneumatic valve bodies are printed with a CR-BK rigid manifold and a CE-BK-rich D70 circumferential sealing bead for pilot valve evaluation. The sealing bead replaces a moulded nitrile O-ring in short-run functional prototypes. The bead cross section is trapezoidal, with a root width of 1.0 mm and a free height of 0.8 mm. Leakage is evaluated at 0.6 MPa air pressure per ISO 5208:2015. The rigid manifold is pressure tested only after orientation-specific tensile coupons per ISO 527-2:2012 confirm that build orientation does not reduce tensile strength below the design requirement. Shore A of the bead is verified per ISO 7619-1:2010 before leak testing. Hardness drift above 75 Shore A reduces lip seating force and increases leakage. The elastomer phase swells in aromatic hydrocarbon fluids; for compressed air and neutral gas service it is stable at the pressures listed. Mineral oil exposure requires immersion testing per ISO 1817:2022 before release. Published data for RBK-EBK-D70 under continuous mineral oil contact is limited. Terminal parts include pilot valve bodies, pneumatic manifold prototypes and vacuum cup adapters. RoHS compliance is from batch material certificates. The CE-BK-rich bead is not intended to replace a standard O-ring in production without endurance testing of 1×10⁶ cycles.

What Limits the D70 Composite in Medical Simulation Models That Require Repeated Autoclave Cleaning?

Medical simulation trainers are printed with CR-BK-rich bone proxies and CE-BK-rich D70 soft-tissue regions for surgical access procedures. The soft-tissue regions use the D70 recipe to approximate the tactile response of 70 Shore A tissue surrogates. The hard/soft interface is generated with an 8–12 layer graded transition to prevent scalpel or trocar-induced tear propagation. Tear strength is measured per ISO 34-1:2015 method B on printed slabs taken from the transition zone. Repeated instrument insertion creates notch-like damage; the tear strength of the elastomer-rich phase should be monitored per ISO 34-1 after every 50 simulated insertions. Steam autoclave cycling at 121 °C is not recommended without formal qualification because published data for RBK-EBK-D70 after repeated autoclave exposure is limited. Dimensional stability after chemical disinfection is checked per ISO 175:2010 at 23 °C. The material system is not certified to ISO 10993-1:2018 unless explicitly stated in batch documentation. Terminal parts include orthopedic incision trainers, vascular access mannequins and laparoscopic skill models. Compliance with 2017/745 is the responsibility of the medical device manufacturer. The CR-BK phase is not intended for implantable use. Users must not clean the D70 composite with strong polar solvents before checking compatibility per ISO 1817:2022 because softening of the elastomer phase may change the surgical response.

End-of-arm tooling fingers for electronics assembly are built with a CR-BK-rich mounting flange and CE-BK-rich D70 contact pads. The D70 contact pad is used where lower contact pressure is required to reduce marking on bare printed circuit boards compared with hardened tool steel. Pinch force is verified with a calibrated load cell in the range 5–15 N. Static coefficient of friction against a stainless steel counterface is measured per ASTM D1894-14. The mounting flange is tapped for M4 fasteners after printing; torque retention is checked at 1.5 N·m. Terminal parts include pick-and-place gripper fingers, PCB clip nests and robotic sorting pads. The elastomer pad should not be used for parts with sharp edge burrs because cut propagation follows the layer interface; edge contact parts require a tear test per ISO 34-1:2015 before production use. Cleanroom compatibility of the D70 composite is not implied; particle generation requires evaluation per ISO 14644-14 if the end-user requires a rated cleanroom environment.