Bunny and Bear Universal Carriage for Bear or Prusa X-axis

thingiverse

NB: Download files individually for the latest BNB9S version. The "download all files" button on Thingiverse is not delivering current files. This universal x-carriage allows you to choose from a variety of Bear or Prusa carriages with your preferred extruder. Supported extruders include Bear/BNB, Prusa, and Bondtech upgrade extruders. The following models are supported: * BNB Short Ears MK3S * Bunny and Bear Short Ears MK3 * Bunny and Bear Geared * Bear * Prusa MK3 R3 * Prusa MK3S R4 * Bondtech I3 Upgrade This x-carriage has belt paths for both Bear and Prusa x-axes. The upper path is for the Bear x-axis, while the lower path is for the Prusa x-axis. Simply push the belt ends into the corresponding slot for your axis. Since this carriage is based on the BNB Easy Motor Service carriage for the Bear extruder, you also get easy access to motor bolts for both BNB and Bear extruders. The BNB Short Ears extruder should clear stock Prusa motor x-end when used with this carriage. --- Assembly Guide: https://bunnyscience.dozuki.com/Guide/BNB+Universal+X-Carriage/3?lang=en For Bear and BNB family extruders: * This carriage moves the extruder 1.5 mm closer to the x-axis, but maintains the same dimensions for most bolts inserted through the x-carriage. * The middle air plenum bolt that connects the extruder body to the x-carriage must be an 8 mm cap head. For Prusa extruders: * The carriage is 1.5 mm thinner than standard Prusa x-carriages, but the bolt bore depths were compensated to maintain bolt lengths. * Please verify proper fitment, especially for the two MK3S R4 extruder bolts passing through the hot end air plenum. * Cable dress should be done in the "Bear" style rather than following Prusa conventions. Combined with the BNB Short Ear Extruders' already pushed back motor, this carriage moves the motor to a fraction of a mm in front of the Z-axis T-nut. Bunnies have verified this carriage on both Bear and Prusa x-axes, and it works as intended. Just be sure to use the correct insertion slot - top for Bear, bottom for Prusa. It's also best to insert a short piece (two teeth long is sufficient) of belt into the empty slot before attaching the belt ends. Genuine Gates 2GT belts are thinner and easier to insert than most Chinese GT2 belts. As with the Skelestruder, you should stiffen the belt holding teeth of the carriage by stuffing the unused belt path with a two-tooth-long piece of 2GT belt. Please print all three parts of this carriage rather than attempting to mix with older x-covers. If used with short body MKS3 sensor extruders, double-check lead dress for hot end wires when the x-carriage is max left and the print bed is max forward before XYZ calibration. Use the current BNB Universal x-carriage, which has better cable passage for the hot end. --- Change Log: BNB7S: The upper cover is now secured with 5 screws to symmetrically balance clamping forces on each bearing. Mid-plenum screw is now M3 x 8 mm, but should be a cap head instead of socket head, especially if used on Prusa axis. Added spacer for use when the extruder is BNBSX. The spacer allows standard M3 x 30 mm screws for the upper left motor bay screw. BNB8S: Tightened the central portion of the belt path by 0.2 mm. BNB9S: Self-aligning bearing pockets and improved nut pockets were added. The carriage was changed to a short bottom cover that permits belt access without removing the lower cover. BNB9Si: Improved printability of overhanging bolt recesses with sacrificial membranes. Printing as a thin, but complete overhang results in cleaner geometry. Drill through membranes to open through holes.