Compact Prusa MK3S/MMU2S BMG Mosquito Extruder

Description

I wanted to make a Mosquito Hotend compatible BMG extruder which would pass normal MK3S firmware calibration and require no hotend mounting adapter. This extruder has the same filament path length and height as the stock MK3S extruder so it passes stock calibration perfectly and so the only change you need to make is to your e-steps via Pronterface or Octoprint terminal. Features: - Passes stock MK3S firmware calibration without any tricks. This means you maintain the full 210mm Z height, instead of other BMG designs which make you lose 5 -10mm. - Simple Mosquito (or Magnum) Hotend mounting without an adapter or groove mount that allows it to be installed and removed completely without disassembling the extruder while still allowing single hand nozzle swaps! - Full Bondtech BMG support and the extruder easily disassembles using 4 screws behind the carriage - TheZeroBeast's IR sensor mod allows MK3S or MMU2S universal compatibility (https://www.prusaprinters.org/prints/7690) - Bear extruder PINDA mount (super strong) - Designed to use the Universal BunnyScience X-carriage ( https://www.thingiverse.com/thing:3610593) - Special Dual Fan duct designed specifically for this extruder (not mandatory) - Full Mosquito Hotend silicone sock support (https://www.thingiverse.com/thing:3793665) ----------------------------- MAJOR UPDATE 6/4/2020: After two months of testing I have uploaded V4 of this extruder that integrates TheZeroBeast's IR sensor mod into the extruder housing making this design lighter, more compact and more accurate for MMU printing! This required a major redesign of most of the extruder including replacing the idler door to something closer to stock and changing the lid configurations. The design is now universal as it can be used with or without the MMU2S attached. Additionally I have improved the 40mm fan airflow path and uploaded an untested BLTouch version for people going the SKR route. I have prefixed all new files with V4 and uploaded new images. UPDATE 4/5/2020: Added Dual Fan Duct v5, this is a very different approach to dual fans compared to v4. It is basically a heavily remixed RHD fan duct adapted for 2 fans. This improves cooling and maintenance. The issue I had with v4 was back pressure and vibration from the right fan when using 2 LDO high speed fans. This design completely removes the back pressure and reduces vibration (I recommend printing the support in TPU if you have 2 LDO fans). This design is far easier to install and remove and weighs about 50% less than v4 including the support bracket. The only thing you sacrifice is the ability to see the print clearly while printing. UPDATE 3/17/2020: Added Dual Fan Duct v4, this has a few improvements to the duct design. The ducts are more angled to direct air directly below the nozzle for better cooling from all angles. This provides significantly better cooling than the single fan ducts in an enclosure, no issues with angles up to 75 degrees. The duct openings are further from heatblock so they will not warp even under extreme no fan conditions (I did a 7 hour PC print at 280 with no impact on the ducts!). UPDATE 3/15/2020: Added a remixed version of the new RHD Mosquito Fan Duct. This requires the RHD Fan Support to work. The performance of this duct is slightly better than the Single Fan Duct v1.5 on overhangs based on my non-scientific testing but still worse than the Dual Fan Duct. --------------------------------------------- Installation: 1. I used PETG for my initial design tests but settled on PC-ABS (Protopasta) for the final design due to high temp resistance, high strength, and lower density without the brittleness of full Polycarbonate. 2. Pre-thread all screw holes such as the lever, sensor and 40mm fan mounting holes. I also suggest drilling out the filament path in the body with a 2.5mm or 3/32" drill bit. Make sure screws slide easily through passthrough holes as labeled in the pictures. 3. Add all square nuts to the cover (5) and body (2). I recommend using some tack or other removable adhesive on the square nuts to hold them in place if the holes are slightly too loose. 4. There is a diagonal cut in the pinda probe mount that you need to cut through as the pinda holder will hit the X-end if it is not cut. (see pic) 5. The Lever should be installed using a 12mm screw, I use a nylon washer to help it move but it is not necessary. The magnets should attract to each other instead of repel like the stock design. 6. Use a 6mm M3 screw for the angled left mounting hole for the Extruder motor, 8mm works too but is much harder to angle in. 8mm works perfectly for the right hole. 7. The Bunny Universal Carriage needs the lower plate as the extruder cover needs screws inserted from the back of the printer. The carriage is also a bit thinner so the uploaded spacer allows you to use a 50mm screw in the bottom left without hitting the motor. Use 45mm screws for the top and right extruder mounting holes. 8. I used nylon washers to allow the idler door to swing more easily, its not necessary though. I also installed a 6mm M2.5 screw in the door to act as a handle for opening more easily. 9. The side fan mounting holes are extended to allow up to 16mm screws, the lower right screw hole extends into the fan duct square nut so use a 18mm screw there. 10. The mosquito hotend mounting holes use the M2.5 screws that come with the hotend in black, 2 are longer and 2 are shorter. If you can acquire two 20mm M2.5 screws instead then you only need to screw them in from one side. If you use the PINDA side you no longer need to remove the 40mm fan to remove the hotend! 11. Two PTFE cutting jigs have been uploaded to make exact sized tubes. The PC4-M10 version extends the upper tube to 22mm to improve the filament path. Make sure to trim open (widen the hole) the top of both ptfe tubes with a blade to facilitate filament loading. 12. Make sure to set your e-steps correctly via gcode for the BMG gear ratio: Standard 1.8 degree motor - M92 E830, M500 0.9 degree motor - M350 E16, M92 E830, M500 13. The Pin should be trimmed based on simple testing using the 'Support>Sensor Info' menu item. Just insert your softest filament into the extruder and the sensor should trigger (1), if it doesn't then your pin needs to be very slightly cut at the tip or your magnets are installed incorrectly. Having this tuned is key for perfect MMU prints. ----------------------------- DISCLAIMERS: I own no rights to any of these designs, I merely combined a lot of them and made some tweaks to accommodate screws and nuts. I am NOT a designer or engineer, simply a hobby enthusiast who dabbles in upgrades. All thanks and credit goes to the original designers: Guy Kuo - Bunny Science Jerry Stegenga - MK3S Mosquito Extruder Juan Puchol - Mosquito Bondtech BMG Extruder Marco Zambon - Bondtech BMG FDM Extruder Stefan Weber - Mosquito Bondtech BMG Extruder Grégoire Saunier - Bear Extruder Robert McKenzie 'TheZeroBeast' - IR Sensor Mod Roy Henriksson 'RH_Dreambox - RHD Fan Duct Jonathan R Swift - Dual Fan for Prusa Extruders ------------------------------------------ NOTE: All of the below instructions are for V3.5 or earlier versions ONLY. DO NOT USE for V4 or newer. Make sure you print the following missing items from one of the remix sources before you install your extruder if you don't already have them! I didn't want to upload files that I made no changes to as they are completely someone else's work. - Idler Door/Lever from https://www.thingiverse.com/thing:3652205 (MMU2S) OR https://www.thingiverse.com/thing:3469271 (MK3S) - Sensor/extruder lid from https://www.thingiverse.com/thing:3652205 OR https://www.thingiverse.com/thing:3469271 - Sensor lever for MK3S from https://www.thingiverse.com/thing:3469271 - X-carriage for MK3S from https://www.thingiverse.com/thing:3610593 (You MUST use this carriage for MK3S version due to sensor cutout) - X-carriage for MMU2S based on your x-axis parts from https://www.thingiverse.com/thing:3610593 OR https://github.com/gregsaun/bear_extruder_and_x_axis/tree/master/optional_parts/bondtech_x_carriage OR https://www.thingiverse.com/thing:3472470 OR https://www.thingiverse.com/thing:3652205 NOTE: This extruder is not compatible with the BunnyScience X-Axis Motor mount due to the extruder motor wire management duct shape. It will work with all other x-axis mounts (Stock, Zaribo, Bear) - Easy Access back bottom plate for standard x-carriages: https://www.thingiverse.com/thing:3681214 - Mosquito Silicone Sock from https://www.thingiverse.com/thing:3793665 - Prior to printing decide whether you need the MK3S body with the upper IR sensor space or a direct filament path with the MMU2 version. All screws and nuts used in this design are M3 except the hotend mounting screws which use M2.5 included with the Mosquito kit. - Make sure to ADD support enforcers or manual supports to the idler lever area of the extruder body since its a serious overhang. No other part or area needs supports in this design. (see pic) - If you use the Dual Fan duct V4, the center mounting hole uses a 10mm screw and the right arm mount uses an 8mm screw. The arm screw goes in from the back of the extruder cover where it has the hex nut impression. This was done to maintain compatibility with the stock duct and improve rigidity.

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