⬢Pay great attention to the cable management, if you miss some important step you would need to disassemble the extruder.
⬢This bag includes extra fasteners, printed parts. Don't worry if you finish with few unused items.
⬢The MK3S/2.5S upgrade package also include magnets, which are used on the single material version and are not needed when assembling the MMU2S upgrade. We include them as an extra if you decide to switch to a single material.
ATTENTION: use the Bondtech gears recovered from your printer. Also, make sure you have all the parts and you are using correct ones.
⬢Use now: Bondtech gear with a lock screw. If the screw is out, gently screw it in (leave space inside for the shaft).
⬢Use later: Bondtech without a lock screw, bearings and a shaft. Keep the bearings somewhere safe, they tend to roll away ;)
In case of upgrading from MMU1 to MMU2S, reuse the Extruder motor from the disassembled printer. Don't use the Extruder motor from the MMU1, the cable is not long enough.
⬢Take a piece of the 1.75mm filament. You can use the bundled one on a spool, don't use the black nylon, which is too thick. Straighten the filament as much as possible.
⬢Place the filament along the path and align the gear properly.
⬢The filament will be always slightly bent. Use it anyway for the initial alignment.
⬢For a final check replace the filament with an Allen key. Bear in mind, the key has slightly different size than the filament.
⬢Tighten the screw slightly to temporarily fix it, we will make the final check and tightening later on. Be careful, you can strip the thread.
Don't use any glue to fix the screw in place, you won't be able to release it, in such case you might have to replace the entire motor.
⬢Take the orange Adapter-printer-mmu2s (without hole for steel ball) and insert it in the Extruder-body. The surfaces of both parts should be almost aligned.
DON'T use any screw to secure the Adapter-printer-mmu2s. It should hold inside the Extruder-body by itself.
⬢Take two M3x10 screws and insert them in the holes. Doing this now makes the assembly slightly easier, but both holes are shallow and the screws might fall out. If this happens, you can continue without them and put them back later on (you will be notified). Also note, that in few upcoming pictures the screws might be missing.
For the following nut insertion USE A SCREW. THAT'S AN ORDER!!! Seriously, use a screw to pull the nuts in, both have to be properly seated in the X-carriage.
⬢Take both M3n nuts and using pliers (or screw) push them in the X-carriage, then using a screw from the other side, pull them all the way in.
⬢Don't forget to remove the screw.
⬢Take all four M3nS nuts and insert them in. Ensure correct alignment using the Allen key.
From now on, keep in mind the nuts are inside, avoid rotating the X-carriage "downwards", or the nuts might fall out.
In case the nuts keep falling out, use short screws from the spare bag to fix them temporarily.
Following cable management is CRUCIAL for the extruder TO WORK PROPERLY! Read the instructions carefully.
⬢Start by making a small loop just below the extruder motor. Leave a slack about 2-3 cm (0.8 - 1.6 inch) This is comes handy for easier disassembly in the future.
⬢Then guide the cable in the "channel" all the way to the back.
⬢Slightly bend the cable down to form it around the edge.
Also, prepare X-carriage, both M3x10 screws (if you haven't used them already) and the longest Allen key with the ball-end, you will need it.
Following cable management is CRUCIAL for the extruder TO WORK PROPERLY! Read the instructions carefully.
Before you assemble the X-carriage, check the nuts in the Extruder body are still in place. The upper nut sometimes falls out.
⬢Grab the X-carriage and place it from the back of the extruder.
⬢Make sure the motor cable follows the channel both in Extruder-body and X-carriage. In the X-carriage the motor cable will follow the path of the IR-sensor cable.
⬢ENSURE NO WIRE IS PINCHED! Then use the M3x10 screw and Allen key with ball end to connect both parts together. If you are inserting the screw at this moment, it will be slightly inclined in the beginning, but it will "straighten up" after few turns. Don't tighten the screw completely, we need to adjust the IR-sensor cable.
⬢Turn the extruder to the other side and if needed insert the second M3x10 screw. Don't tighten the screw, we need to adjust the IR-sensor cable.
⬢Flip the FS-cover assembly on top of the Extruder.
⬢Align the left edge with the extruder body.
⬢Use a M3x18 screw to join both parts together.
⬢The IR-sensor cable can go straight in the extruder, no need for any additional loop. Carefully pull the cable, contrary if the cable is stretched, push it slightly in.
⬢Finish the sensor assembly by inserting an M3x40 screw.
⬢Make sure all the gaps are gone.
The IR filament sensor position will be calibrated later in the upcoming chapter. Without the proper calibration, the MMU2S won't be able to work properly.
The fan has two sides, one has a Noctua sticker. Make sure, this side is facing inside the extruder.
⬢First, create a loop on the cable. Make sure the black protective wrap is close to the edge of the fan. See the picture.
⬢Place the fan on the extruder and proceed in the following way:
⬢Start by placing the fan's cable in the upper channel.
⬢Slide the fan close to the X-carriage and GENTLY PUSH the cable in using an Allen key. Before you push the fan all the way to the left, place the cable in the X-carriage channel.
FINAL CHECK! The fan is oriented with the cable facing up, then the cable goes through the upper channel all the way to the X-carriage. In the X-carriage don't forget to use both channels. Make sure the CABLE ISN'T PINCHED along the way!
⬢Use the three M3x14 screws to fix the fan in place. Don't over tighten them, you can break the fan's plastic casing. Also make sure the fan can rotate freely.
Note that the screws are "self-tapping" in the printed parts. There are no nuts.
⬢Take M3n nut and place it in the Extruder-idler-mmu2s.
Use the screw pulling technique.
⬢Insert the pulley in idler as shown in the picture.
⬢Slide the shaft through the idler and pulley. Use reasonable force or you will BREAK the printed part. In case of a self-printed part, please drill both holes for the shaft with a 3mm drill before inserting the shaft.
⬢Place your finger on the bearing and ensure it can rotate freely.
⬢Place the Extruder-idler-mmu2s in place and secure it using a M3x40 screw.
⬢Don't tighten the screw too firmly, it serves as a shaft for the idler. Check that the idler can rotate freely (though the range of the movement is small).
The fan-shroud was initially designed for M3x18 screw, but based on the feedback and to make the assembly more convenient, use M3x20. If your extruder bag includes only two M3x20 screws, please use another one from the spare bag.
⬢Insert M3nS nut in the Fan-shroud, all the way in.
Ensure correct alignment using the Allen key.
⬢Mount the Fan-shroud to the extruder, secure it using an M3x20 screw. Don't over tighten the screw, you can break the fan's plastic casing. Also make sure the fan can rotate freely.
⬢Insert the zip ties in the X-carriage like in the picture.
⬢Lower the X-axis at about 1/3 from the top.
⬢Turn the printer with X-axis motor and PSU facing towards you. LCD is on the other side. Align the bearings similarly to the picture. The exact position of the lower bearing doesn't matter for now.
⬢Place the extruder on the bearings, the top couple must fit perfectly. Make sure the X-carriage with the "belt inserts" is facing towards you.
⬢We will adjust the lower bearing later on.
⬢Tighten and cut the zip ties.
Check all the square M3nS nuts are still in the X-carriage.
⬢Using right hand rotate the motor to its original position and hold it (tension is applied to the belt).
⬢Using two fingers on your left hand push the belt together. Very small force should be needed for bending the belt, BUT the belt shouldn't be bent by its own weight before being pressed with your fingers, it must be straight.
If you are struggling to rotate the motor back into position, the belt tension is too high.
⬢Depending on the belt being under or overstretched, adjust the amount of the belt in the X-carriage.
⬢When done, rotate the motor to its original position and tighten the M3 screws again.
⬢Use the technique described below to test if the belt is properly stretched.
⬢Use pliers to hold the X-axis motor shaft.
⬢Move the extruder towards the X-axis motor. Don't use excessive force.
⬢If the belt is stretched properly, you should feel a resistance and the extruder won't move at all. If the belt is too loose, it will deform (create a "wave") and jump over the teeth on the pulley.
Belt too loose? Return to step 48 and repeat all steps until now. You have to rotate the motor and retighten the belt in the X-carriage. Shortening the belt length by moving one or two teeth outside X-carriage should be enough.
Your belt might be already trimmed, simply skip the trimming instructions and insert it in the X-carriage.
For the following step we recommend getting a white marker, but you can also trim the belt without it.
⬢Measure the part, which must be trimmed and gently take the end of the belt away, from the X-carriage, but make sure at least 3-4 teeth are still in the X-carriage, as you don't want to lose the tension. If possible make a mark, where to cut the belt.
⬢Ensure again your mark is in the correct position and the belt is still stretched.
⬢Using pliers cut the belt and push it inside X-carriage. Use screwdriver or Allen key, if needed.
In this step, we will finish tensioning the belt. Please read the instructions first, your belt might have proper tension already.
⬢First, slightly release all the screws holding the motor, otherwise, the upper "tensioner" won't work (the motor must be able to move).
ATTENTION !!! BE EXTREMELY CAREFUL WHILE TIGHTENING, YOU CAN CRACK THE PART IF YOU OVER TIGHTEN THE SCREW.
⬢Using Allen key start tightening the M3x18 screw inside the X-end-motor, but after each turn or two check the tension in the belt.
⬢For the optimal performance, the belt must be a bit harder to press with your fingers. Move the extruder all the way to the X-end-idler and try the belt tension in the middle of the X-axis.
⬢When you achieve optimal tension, please tighten the screws again.
In case you experience X-axis failure during calibration or skipped layers in the X direction, you can adjust this screw accordingly. Tightening the screw stretches the belt. Releasing the screw has opposite effect. Each time don't forget to release the screws on the motor first.
⬢Locate the hole for the NYLON filament. Using the smallest Allen key ensure there are no obstacles inside.
⬢Using the pliers insert and twist the NYLON filament in the slot. Hold the extruder with your other hand.
BE EXTREMELY CAREFUL as the pliers tend to slide and you can easily damage the wires!!!
⬢To check if the filament is seated properly, gently pull it with your hand. The X-axis should bend a little, but the filament must remain in the slot.
⬢If you have issues, try to adjust the tip on the filament.
MK2.5S extruder differs from now on! Please use another chapter and then return here MK2.5S extruder cable management. Follow the linked chapter to the very end, apart from the cables and different printed Cable-holder, you need add one printed part (Endstop-block).
MK2.5S users only: after you return back to this chapter, you can skip to the Step 64.