⬢Aluminum extrusions (4x)

⬢Aluminum frame (1x)

⬢M5x16r screw (16x)

⬢Take the LONGER aluminum extrusions and place them next to the frame.

Note: screws are inserted from the opposite side of the frame. If you need to manipulate with the frame, make sure the extrusions are on the correct side.

⬢Ensure you are using the correct holes, see the second picture. Use the M5 screws to connect extrusions to the frame. Tighten the screws with the Allen key just slightly!

⬢Now, tighten the screws fully, but ON A DIAGONAL, see the last picture. As soon as you finish the first, tighten the second pair. Then proceed to the second long extrusion.

⬢Take the SHORTER aluminum extrusions and place them next to the frame.

Note: screws are inserted from the opposite side of the frame. If you need to manipulate with the frame, make sure the extrusions are on the correct side.

⬢Ensure you are using the correct holes, see the second picture. Use the M5x16 screws to connect extrusions to the frame. Tighten the screws just slightly!

⬢Now, tighten the screws fully, but ON A DIAGONAL, see the last picture. As soon as you finish the first, tighten the second pair. Then proceed to the second short extrusion.

⬢Front plate (1x)

⬢Rear plate (1x)

⬢M5x16r screw (16x)

⬢PSU holders M3nE (2x)

⬢Rotate the frame with longer extrusions towards you.

⬢Place the front plate on the extrusions and secure it with M5x16r screws, DON'T TIGHTEN them yet!

⬢Now, tighten the screws fully, but ON A DIAGONAL, see the second picture. As soon as you finish the first, tighten the second pair. Then proceed to the second long extrusion.

⬢Take the YZ frame and rotate it with the shorter extrusions towards you.

⬢Place the PSU holders (M3nE) in the extrusion, use the side section, ensure it is the correct extrusion. See the picture.

The exact spacing of the PSU holders doesn't matter, we will adjust them later.

⬢Take the YZ frame and rotate it with the shorter extrusions towards you.

⬢Place the PSU holders (M3nE) in the extrusion, use the top section, ensure it is the correct extrusion. See the picture.

The exact spacing of the PSU holders doesn't matter, we will adjust them later.

⬢Ensure the frame with shorter extrusions is rotated towards you.

⬢Place the rear plate on the extrusions and secure it with M5x16r screws, DON'T TIGHTEN them yet!

⬢Now, tighten the screws fully, but ON A DIAGONAL, see the second picture. As soon as you finish the first, tighten the second pair. Then proceed to the second short extrusion.

⬢All the components are cut or drilled by machine for highest precision, but with uneven tightening, it is possible to warp the frame.

⬢Using your hand, try to wiggle with the frame sides and check, whether some corners are lifting up or not.

⬢In case you find some imperfections, release the screws, press the extrusions against the FLAT SURFACE and tighten them again.

Note this step is optional for now. We recommend mounting the feet now to protect the surface on your table (workbench). However, you need to lift the frame up before each turn.

There will be extra step at the end of the assembly to remind you of the antivibration feet.

Note there are two designs of the feet, your package will have either the new version (marked orange) or the old version (marked red).

⬢Turn the YZ frame on the side and insert the antivibration foot. For the new design, insert and turn 90 degrees to lock it in place. For the old design insert inclined, then rotate the foot until you squish the rim inside the extrusion.

⬢Repeat this process on all 4 feet. Place them 2-3 cm from the end of each extrusion.

⬢Y-rod-holder (4x)

⬢M3x10 screw (8x)

⬢M3nS nut (8x)

⬢Take one Y-rod-holder and insert two M3nS nuts.

⬢Make sure you've pressed the nuts all the way in. You can use pliers, BUT be careful, you can damage the printed part.

In case you can't press the nuts in, don't use excessive force. First, check if there isn't any obstacle in the nut trap.

⬢Ensure and adjust the alignment of each nut with the 2mm Allen key.

⬢Repeat this step for the remaining Y-rod-holders.

⬢Take the first pair of Y-rod-holders and place them on the longer extrusions, openings for screws must be facing up.

⬢Rotate the 3D printed parts towards the front plate.

⬢Secure each front holder with two M3x10 screws. Tighten both screws equally, but not completely. We will tighten them fully later on.

⬢Take the second pair of the Y-rod-holders and secure them with M3x10 screws on the rear plate (with shorter extrusions). Tighten both screws equally, but not completely. We will tighten them fully later on.

In case the M3nS nuts keep falling out, please flip the frame upside down. Tighten both printed parts and then return the frame to the previous position.

⬢Take the Y-belt-idler and insert two M3n nuts from the top.

⬢Turn the idler to the other side and insert the M3nN nyloc nut. The rubber inside the nut must be facing towards you. BE CAREFUL, don't over tighten the screw, you can break the part!

⬢Make sure all three nuts are all the way in.

In case you can't press the nuts in, don't use excessive force. Take M3 screw thread it from the opposite side of the printed part, as you tighten the screw, it will pull the nut in. Be careful not to break the idler during tightening.

⬢Insert the prepared bearing in the Y-belt-idler.

Bearing housing orientation doesn't matter.

⬢Secure the bearing with the M3x18 screw. Don't fully tighten the screw.

⬢Place your finger on the bearing and ensure it can rotate freely. If needed adjust the screw.

⬢For the following steps, please prepare:

⬢Y-axis motor (1x)

⬢Y-motor-holder (1x)

⬢M3x10 screw (4x)

⬢M3n nut (2x)

⬢Take the Y-motor-holder and insert two M3n nuts.

In case you can't press the nuts in, don't use excessive force. Use an M3 screw from the other side and tighten it.

⬢Place the Y-motor-holder on the motor, ensure the correct orientation as in the picture (use the motor cable).

⬢Using two M3x10 screws tighten holder and motor together.

⬢For the following steps, please prepare:

⬢Y-carriage (1x)

⬢U-bolt (3x)

⬢Linear bearing (3x)

⬢M3nN nyloc nut (6x)

⬢The printer's package contains a lubricant, which is intended for maintenance. No need to use it now the bearings are lubricated. There is a dedicated online manual on how to clean the printer and apply the lubricant. See help.prusa3d.com/maintenance-tips

For MK2/S owners, the Y-carriage is now symmetrical in one direction, therefore the dot (countersink, marker) orientation for bearing insertion doesn't matter.

⬢The correct orientation: When placing bearings onto the Y-carriage, make sure that they are oriented as shown in both pictures. The tracks (rows of balls) have to be on the sides.

The printed version of this manual (v3.14 and older) suggests a different approach, please follow the online version instead.

⬢Place the Y-carriage on a flat surface. Orientation doesn't matter.

⬢Insert linear bearing in the cutout and secure it by U-bolt.

⬢Hold thumb on the U-bolt and turn the carriage. Place nyloc nuts on both ends of the U-bolt.

⬢Start tightening the nuts, BUT ENSURE you are tightening both nuts equally and AS SOON AS EACH NUT REACHES THE SURFACE OF THE Y-CARRIAGE STOP TIGHTENING!!! We will finish tightening the nuts in the next step.

⬢Repeat these steps for the remaining two linear bearings.

Over tightening nuts leads to deformation of the bearing and all the issues connected with it. Please follow the instructions.

⬢Check if the bearing is centered in both directions, if not slightly release the nuts and adjust its position. Then retighten the nuts to the previous state.

⬢When you are ready, using pliers rotate each nut, but only 90°. This is enough to fix the bearing without deforming it.

⬢Repeat these steps for remaining two linear bearings.

⬢Take all the smooth rods and compare their lengths. For Y-carriage you need mid-sized rods (330 mm).

⬢If you can't slide the smooth rod easily, check the two bearings are aligned properly.

In case you manage to push out balls from the bearings, please count them. One or two balls are ok, if there are more of them, please consider ordering new bearings.

⬢Take the Y-carriage including smooth rods and place them in YZ-frame. Make sure, that two bearings are on the left side (see the picture).

⬢Using your thumb, press the smooth rods inside all four holders. Don't use excessive force.

⬢Find the package with zip ties and take out 4 pieces.

⬢Slide the zip tie through the holder, there is a slot.

⬢Connect the zip tie and tighten it. The "head" should be inside the frame.

⬢Using pliers cut the remaining part.

⬢Repeat this step in all four corners.

⬢Ensure all M3x10 screws on Y-holders are slightly loosened, so the printed parts are able to move.

⬢Move the Y-carriage back and forth across the entire length of the smooth rods to align them.

⬢Then move the carriage to the front plate and tighten all screws in the front-Y-holders.

⬢Move the Y-carriage to the rear plate and tighten all screws in the back-Y-holders.

⬢There is a flat part on the motor shaft, rotate it similarly to the first picture. See the direction of the arrows.

⬢Place a GT2-16 pulley on the Y-motor shaft as shown in the picture.

⬢Don't press the pulley against the motor. Leave a gap so the pulley can rotate freely.

⬢One of the screws must be facing directly against the pad (flat part) on the shaft. Slightly tighten the first screw.

⬢Turn the shaft and slightly tighten the second screw.

Don't tighten the pulley firmly yet, we'll get to that later.

⬢Take the Y-belt-holder (smaller of the two printed parts).

⬢Insert M3n nut, all the way in.

⬢Insert M3nN nyloc nut, all the way in.

Use the screw pulling technique.

⬢Bend one end of the belt around M3x10 screw.

⬢Push it in the holder as in the picture. Use an Allen key to push the belt in.

⬢Make sure the bent part and the end are within the width of the printed part.

⬢Teeth on the belt must be facing up!

⬢Tighten the screw until you reach the nut, don't over tighten the screw, you will deform the belt.

⬢Hold the nut from the other side until the screw reaches its thread.

⬢Using M3x10 screw fix the Y-belt-holder to the Y-carriage. Tighten the screw and ensure the printed part is parallel with the "axis" between the Y-motor and Y-belt-idler.

⬢Use the hole on the left, see the picture.

⬢Guide the belt along the Y-axis, around the pulley on the Y-motor and back.

⬢Make sure the belt is inside the frame, not under!

⬢Push the belt through the Y-belt-idler and back to the "center" of the Y-carriage.

⬢Take the Y-belt-tensioner (bigger of the two printed parts).

⬢Insert M3n nut, all the way in.

Use the screw pulling technique.

⬢Bend second end of the belt around the screw and push it in the holder as in the picture. Use an Allen key to push the belt in.

⬢Make sure the bent part and the end are within the width of the printed part.

⬢Teeth on the belt must be facing up!

⬢Tighten the screw until you reach the nut, don't over tighten the screw, you will deform the belt.

⬢Hold the nut from the other side until the screw reaches its thread.

⬢Using M3x10 screw fix the Y-belt-tensioner to the Y-carriage. Don't tighten the screw completely, we need to adjust the position of the printed part.

⬢Use the hole on the right, see the picture.

⬢Insert the M3x30 screw through both printed parts. Start tightening until you reach the M3nN nyloc nut.

⬢Using a finger on your left hand push the belt down. Some force should be needed for bending the belt, BUT don't try to overstretch the belt as you might damage the printer.

⬢You can change the tension in the belt by adjusting the M3x30 screw below the Y-carriage.

⬢Use the technique described below to test if the belt is properly stretched.

⬢Use pliers to hold the Y-axis motor shaft.

⬢Move the Y-carriage with your hand towards the Y-axis motor. Don't use excessive force.

⬢If the belt is stretched properly, you should feel a resistance and the Y-carriage 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.

⬢After the proper tension is set, tighten the M3x10 screw.