⬢Please prepare tools for this chapter:
⬢1.5mm Allen key
⬢2.5mm Allen key for M3 screws
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- Original Prusa MMU3 Assembly
- 9C. MK3S+ Extruder (UPG)
9C. MK3S+ Extruder (UPG)
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- Original Prusa MMU3 Assembly
- 1. Introduction
- 2. MMU2S Disassembly (UPG)
- 3. MMU2S Buffer Disassembly (UPG)
- 4. Idler Body Assembly
- 5. Selector Assembly
- 6. Pulley Body Assembly
- 7. Cassette Buffer Assembly
- 8. Spool holder Assembly
- 9A. MK4/S, MK3.9/S Nextruder mod
- 9B. MK3S+ / MK3.5 Extruder mod (KIT)
- 9C. MK3S+ Extruder (UPG)
- 1. Tools necessary for this chapter
- 2. Introduction
- 3. Old chimney disassembly (part 1)
- 4. Old chimney disassembly (part 2)
- 5. Old chimney disassembly (part 3)
- 6. Hotend PTFE tube INFO
- 7. Fan removal
- 8. Splitting the extruder
- 9. Partial extruder disassembly
- 10. PTFE tube parts preparation
- 11. Old PTFE tube removal
- 12. New PTFE tube installation
- 13. Extruder reassembly (Part 1)
- 14. Extruder reassembly (Part 2)
- 15. Extruder reassembly (Part 3)
- 16. Extruder fan reassembly
- 17. New chimney: parts preparation
- 18. New chimney assembly (part1)
- 19. New chimney assembly (part 2)
- 20. New chimney assembly (part 3)
- 21. IR Filament sensor: parts preparation
- 22. IR Filament sensor assembly
- 23. Extruder-idler-mmu2s parts preparation.
- 24. Bondtech lubrication
- 25. Extruder-idler-mmu2s installation.
- 26. Opening the electronics box
- 10A. MK4/S, MK3.9/S Setup and Calibration
- 10B. MK3S+ Setup and Calibration
- 10C. MK3.5 Setup and Calibration
- 11. First Flight
9C. MK3S+ Extruder (UPG)
Relevant for:
Last updated a year ago Difficulty
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⬢Your MMU unit is now ready. In the following steps, we will work on the extruder. Namely, the filament sensor inside the "chimney".
⬢First, make sure the extruder PTFE tube with the fittings is removed from the printer.
⬢Remove the M3x40 idler tension screw with the spring and set it aside for later use.
⬢Remove the M3x40 screw from the back of the extruder.
⬢Remove the idler door.
⬢Using the 1.5mm hex key, remove the M2x8 screw and set it aside for later use.
⬢Remove the cover. Set it aside so that it won't mix up with the new parts.
⬢Disconnect the plug from the IR Filament sensor.
⬢Remove the IR Filament sensor and set it aside for later use.
⬢Remove the M3x18 screw and set it aside for later use.
⬢Remove the M3x10 screw.
⬢Remove the old FS-cover and set it aside so it won't mix up with the new parts.
⬢Pull the cable out From the ir-sensor-holder part.
Note the connector orientation on the picture. This way, the connector will pull out of the part easily without a risk of damaging it.
⬢Remove the ir-sensor-holder and set it aside so it won't mix up with the new parts.
VERY IMPORTANT INFO! READ CAREFULLY!!
⬢There is a short PTFE tube inside the extruder’s hotend. It plays a major role in the MMU operation. This tube cools down a molten filament tip to form a narrow sharp end on it, while the MMU does a material change.
The tube is considered a consumable as it wears down over time during the regular use. Therefore, it should be replaced once in a while, after the printer went over certain amount of material changes. We strongly recommend replacing it now, since the extruder is partly disassembled already.
⬢
A new hotend PTFE tube has a 1.85mm internal diameter. If your printer is new or very lightly used, you can skip the PTFE replacement in the upcoming steps and proceed to "New chimney: parts preparation."
⬢
The specimen on the right, however, was taken off a printer after approx. 20000 material changes, using a high-temperature abrasive filament that wore down the tube’s bore up to 2.4mm. This caused increased stringing and malformed filament tips, leading to frequent MMU filament loading problems on that machine. The worn PTFE tube needed replacement.
⬢Release and remove all screws holding the Hotend fan on the side.
⬢Remove the fan. We need to split the extruder in order to replace the hotend PTFE tube.
⬢Look at the back of the extruder. Remove the M3x40 screw in the top right corner.
⬢Release both M3x40 screws at the front, just below the extruder motor. Don't remove them completely. We will use them to hold the extruder parts together.
⬢Carefully split the extruder apart by pulling the front out.
⬢Create approx. a 1cm (0.5in) gap similar to the one seen in the picture.
⬢Reach for the hotend and incline its upper part towards the motor. Wiggle it to slide it down.
If the hotend is still stuck inside, release the screws below the motor some more to increase the gap between the printed parts.
⬢BE EXTRA CAUTIOUS with the hotend cables!!! You can break them! Use a reasonable force to pull the hotend out. Don't bend the cables too much.
⬢For the following steps, please prepare:
⬢Hotend PTFE tube (1x)
⬢PTFE for MK3S+ is 42.3mm long, 1.85mm ID, 4mm OD, inner chamfer on one side, outer chamfer on the other.
The bundled PTFE tube is intended for MK3S+ only. The PTFE tubes for MK3S and MK3S+ differ in length.
⬢Press the black plastic collet.
⬢Remove the PTFE tube from the hotend.
⬢While the black collet is still pressed down, push the PTFE tube in and then pull it out. This way, you will disengage the small metal hooks inside the black collet first. If you force the PTFE tube out without the hooks properly disengaged, the PTFE tube can jam inside.
Throw the worn-out PTFE tube immediately to the nearest trash bin to avoid installing it back by accident ;)
⬢Now it is time to insert the new PTFE tube. Note, that each end of the tube is different.
⬢One end of the tube has an outer chamfer. This end must be inside the hotend.
⬢The other side has an inner chamfer. This conical shape is the filament entry. This part must be outside the hotend.
⬢Push the PTFE tube in. Slide it all the way in and hold it!
⬢
Using your other hand pull the collet out while you keep pushing the PTFE tube in. THIS IS CRUCIAL for the hotend to work properly.
⬢After you finish inserting the new PTFE tube, check that the whole hotend is tightened up and nothing got loose during the process.
⬢Re-insert the hotend back into the extruder. Ensure its orientation is the same as seen in the picture.
⬢IT IS CRUCIAL to ensure the hotend is fitted properly in the extruder-body!!! The top of the hotend must fit into the correct recesses in the printed parts. See the second and the third picture for a reference!
⬢Check once again the correct position of the hotend. Look from below the extruder. The heater block should be oriented as seen in the picture. Perpendicular to the printed parts, with the cables pointing to the back.
⬢Guide the thermistor cables above the thick heater cables.
⬢
Take a look from the side of the extruder. The nozzle should be slightly below the printed fan-shroud.
If it is significantly lower than in the picture, your hotend isn’t inserted correctly.
⬢Carefully and slowly push all the parts together.
In case of any significant resistance STOP immediately and check, which part is blocking the movement.
⬢Tighten the two M3x40 screws on the front of the extruder.
⬢Now, look at the back of the extruder. Re-insert and tighten up the M3x40 screw on the right.
⬢Add the fan to the extruder and push it to the back. There are cables behind the fan. You can GENTLY push the cables into the dedicated channel using an Allen key. Before you proceed to attach the fan, make sure all the cables are inside the channel.
Before you proceed to attach the fan, make sure all the cables are inside the channel.
The fan has two sides, one has a sticker with markings on it. Make sure, this side is facing to the inside of the extruder.
⬢Fix the fan using the following screws (depending on the fan version):
⬢M3x14 / M3x16b screw (3x)
⬢M3x20 / M3x22b screw (1x) in the bottom corner.
⬢For the following steps, please prepare:
⬢Chimney base (1x) with the Tappex Microbarb 0006-M5 threaded insert
⬢Chimney (1x)
⬢M3nS nut (1x)
⬢M3 washer (1x)
⬢M3x30 screw (1x)
⬢M3x18 screw (1x)
⬢Take the Chimney part.
⬢Insert the M3nS nut into the marked opening on the bottom of the printed part.
⬢Add Chimney base onto the extruder. Note the correct orientation on the picture.
⬢Make sure the cable is above the Chimney base and oriented as seen in the picture.
⬢Slide the Chimney onto the base part from the right side.
⬢Make sure the cable goes through the channel on the bottom of the Chimney base and goes out on the right side.
⬢Fix the parts together by M3x18 screw. Tighten it up just so that the parts hold on the extruder. Don't tighten it up fully yet. We will need to move the parts later on.
⬢Insert the M3x30 screw into the marked opening on the side of the Chimney Base. Screw it in until it pulls the chimney all the way in.
⬢
Insert the M3 washer into the marked opening in the Chimney Base.
Push it all the way in so that it locks the screw head in place.
⬢Using the 2.5mm Allen key, adjust the position of the washer so that it is centered and you can reach the screw head underneath later on.
⬢For the following steps, please prepare:
⬢IR-sensor cover (1x) The new one
⬢M2x8 screw (1x) you removed from the printer earlier
⬢Prusa IR filament sensor (1x) you removed from the printer earlier
⬢
Attach the IR filament sensor onto the top of the chimney.
Make sure the electronic components on the sensor board are facing down and the three connection pins are in the back.
⬢Add the cover onto the sensor.
⬢Using the 1.5mm Allen key, lock the cover in place with the small M2x8 screw.
You can add a tiny microscopic bit of lubricant onto the thread so that it screws in more easily.
⬢Look at the back of the extruder. Connect the cable to the filament sensor.
Make sure the safety latch on the connector is pointing up and the connector aligns with the pins.
If you plug the connector incorrectly, you can damage the eletronics!!!
⬢For the following steps, please prepare:
⬢M3x40 screw (1x) The one you removed earlier.
⬢M3x40 screw with spring (1x) The one you removed earlier.
⬢Extruder-idler-mmu2s (1x) The one you removed earlier.
Compare the old plastic part to the new one from the upgrade kit. If it has the exact same shape, use the old one. If the shape differs, you might need to transfer the Bondtech gear and the nut into the new plastic part.
MK3S MMU2S Idler is different than MK3S+ MMU2S / MMU3 Idler and cannot be re-used.
⬢PrusaLube (1x) the supplied lubricant
⬢Add a tiny bit of lubricant into the geared part of the Bondtech gear.
⬢Make sure the lubricant doesn’t get into the filament groove.
Do not use excessive amount of lubricant. Just a tiny bit will do.
⬢Install the extruder-idler-mmu2s back onto the extruder.
⬢Fix the part in place by adding a M3x40 screw into the opening at the back of the extruder. Tighten it up just so that it holds in place.
Do not overtighten the screw. Otherwise, the idler won't be able to move freely.
⬢Add the M3x40 tension screw with the spring into the opening on the left side of the extruder.
Hold the idler with one hand while you tighten the tension screw from the other side. The screw head should be aligned or slightly below the surface. That way, the idler is pulled with the correct amount of force.
⬢Undo the M3x40 screw on the Einsy box to open up the electronics box on the printer.
⬢Open up the Einsy-door on the inner side of the electronics box.
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