Description
This MK3/S/+ toolhead design for the Bear X-Axis mod uses Róbert Lőrincz' Orbiter v2.0 extruder and the E3D Revo Micro. As of the time of publication of this extruder, I've been using it virtually non-stop for a month and reliably achieve high-quality results using PLA, PETG, ASA, ABS, and TPU.
Many of the design choices that I made assume the use Klipper firmware, although the core functionality of the extruder should also work with Prusa-Marlin. The optional BLTouch or BIQU microprobe versions, optional Turbiter stepper fan, and optional Orbiter filament sensor will, to my knowledge, only work with a non-stock MCU. If you're on stock(ish) Prusa-Marlin and still need a filament sensor, you might try something like this frame-mounted sensor holder that uses the stock MK3S/+ sensor.
Update 5/7/2023: Added an additional varient of the extruder body with a mount for the BIQU microprobe. Probe x/y offset remains the same as for the stock PINDA probe (as well as the BLTouch variant of this extruder).
To do: Add some channels and zip-tie mounts for tidier wire management.
Features / Design Choices
- Total height of toolhead is reduced by ~10cm, as compared to the stock MK3/S/+ extruder and most variants built around it. This adds ~10cm to your Z-axis and may require firmware changes. I don't use Prusa's Marlin-based firmware. I can't confirm that this extruder will work with Prusa's stock firmware, nor am I able to provide a custom version of the stock firmware at this time (I may be able to do so in the future). If you're using Klipper, you can adjust the
position_max value for your Z stepper in your config and, if you use a macro to tram your z-axis, you may need to edit it to account for the adjusted axis length.
- Vertical cooling fan to reduce rattling and extend the life of the fan
- Rotated cooling and hotend fan positions allow for shortening the filament path while still being able to mount the cooling fan vertically without it bumping into the extruder stepper motor. Some other MK3/S/+ extruders using the Revo Micro retain the original extruder height / distance between the gears and the hotend. This shorter filament path allows for an overall reduction in weight, increases the functional length of the z-axis, and may help with printing flexibles. Because the cooling fan is rotated, the hotend fan (stock fan that ships with the Revo Micro) has also been repositioned to the other side of the extruder and rotated. You'll need some M2.5 screws to mount it.
- The RHD version of the Bear Extruder Fan Duct doesn't hit the left leadscrew when rotated at this angle, and, in my experience, works just as well (if not slightly better) than the standard Bear duct. The standard Bear duct isn't compatible, as it will hit the leadscrew. I've slightly adjusted the mounting hole on the version of the RHD duct I've uploaded in order to ensure correct positioning. Print the duct in a temperature-resistant material like ASA or ABS. Note: While this fan duct works great, if you're using Klipper, you'll need to make sure your part-cooling fan is PWM-compatible. The Gdstime blower recommended within the Voron 2.4 BOM plays nicely with PWM, Klipper, and this fan duct, and comes in 24v, 12v, and 5v versions. It's sometimes available on Amazon and from 3D printer parts vendors, and can almost always be found on aliexpress. If using Prusa-Marlin firmware, continue using a 3-wire cooling fan, like the one that came with your printer.
- Cable guide is angled upwards to avoid it and your hotend wires hitting the heatbed cover when probing the back left corner of your bed. This cable guide is only compatible with the x-carriage provided with this extruder.
- Compatible with the Orbiter Filament Sensor v2.0. It's recommended that you use the Orbiter Filament Sensor v2.0 if you need/want filament and runout detection. All of the files needed for the printed and PCB components of the sensor are publicly available for self-fabrication, or can be purchased as a kit. An advantage of using a bolted-on (as opposed to integrated) filament sensor is that the entire sensor assembly is easily removable.
- Removing the sensor makes the extruder compatible with the enraged rabbit carrot feeder (ERCF). The ERCF is a Klipper-compatible MMU2S-inspired multimaterial solution that supports up to 9 colors/channels/materials at a time. To use the ERCF with this extruder, forgo or remove the Orbiter sensor and run the ERCF in “sensorless” mode - the encoder in the ERCF will provide runout detection.
- Turbiter (fan holder for the extruder's stepper motor) modified so it doesn't hit the cooling fan. This just involved removing a small amount of material. The turbiter is not required, but may increase the longevity of your Orbiter v2.0 if running it at the recommended current (0.85A), especially if printing within an enclosure. For printing, use a temperature-resistant material like ABS or ASA and print with supports (SLA printing in nylon may yield the best results).
- STLs included for both PINDA and BLTouch sensors. Choose the one that works best for you. One advantage of using a BLTouch is that it enables accurate and high-resolution probing when using adaptive bed-meshing on Klipper (whereas the positions the PINDA can accurately probe are limited based on magnet placement)
Assembly tips
- The top of the Revo Micro hotend is meant to sit flush against the bottom of the Orbiter extruder. You'll need to remove the collet and collet clip from the hotend.
- When seating the Revo Micro, place the extruder_back component on a flat surface. Remove the mounting nut from the Revo Micro threads. Place the threaded part of the Revo Micro on the threaded part of the extruder_back component and gently rotate the hotend until it sits properly within the printed threads. Gently rotate the Revo Micro within the printed threads until the top of the hotend sits flush with the top of the extruder_back component. Place the extruder_front component over the hotend and press it and the extruder_back component together to hold to hold the hotend in place. You may need to maintain pressure to ensure the Revo placement until you've used two M3x40 screws to secure the extruder front, back, and carriage together.
- The length of the PTFE tube you'll need will vary depending on the exact positioning of the hotend within the printed threads and the positioning of the metal filament exit guild that sits below the Bondtech gears in the Orbiter V2.0 extruder. It's recommended that you use a flathead screwdriver to adjust the filament exit guide so that it sits as closely to the gears as possible without touching them. The end of the PTFE tube that goes into the extruder should be carefully drilled out. The side that goes into the hotend doesn't need to be (and shouldn't be) chamfered. To size the tube, place it all the way within the hotend and score it with a hobby knife to mark the position of the top of the hotend. Insert it into the extruder and note the distance between the score mark and the bottom of the extruder. Continue removing material from the extruder side of the PTFE tube until the score mark is ~.25-.5mm from the bottom of the extruder. A small amount of extra length will ensure the PTFE tube remains secure and doesn't slide around during printing (which can affect retractions). Ensuring the Orbiter is securely affixed to the extruder housing should compress the extra length.
Credits
My CAD skills are minimal, so my design relies heavily on the work of others. The mounting points for the Orbiter V2 are based on ZARIBO's Z Orbiter v2.0 extruder. The mounting points for holding together the two halves of the toolhead body and connecting them to the carriage, as well as the PINDA probe holder, are based on MarcoZ76's FDM printable Bondtech BMG extruder. The x-carriage is a modified version of Gregsaun's Bondtech carriage for the Bear x-axis. The Revo Micro mount is adapted from Dsk001's MK3S/+ Extruder Body with E3D Revo Micro Mount. The BLTouch mount is adapted from vertigo235's Bear Extruder BLTouch Mount. This extruder wouldn't be possible without the excellent work of all the people whose work I remixed and I'm grateful to them for sharing their work under open licenses.
iterate
