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7. Y-carriage & Heatbed assembly

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7. Y-carriage & Heatbed assembly

7. Y-carriage & Heatbed assembly
Relevant for:
Last updated 3 months ago
7. Y-carriage & Heatbed assembly
 Difficulty
Moderate
 Steps
67
 Available languages
CSPLDEESITFRJA

Step 1 Tools necessary for this chapter

Tools necessary for this chapter
Tools necessary for this chapter
Tools necessary for this chapter
For this chapter, please prepare:
1.5mm Allen key
2.0 mm Allen key
2.5mm Allen key
Torx T8/10 key
Needle-nose pliers
Phillips screwdriver PH2
Universal wrench

Step 2 Heatbed cable assembly: parts preparation

Heatbed cable assembly: parts preparation
Heatbed cable assembly: parts preparation
Heatbed cable assembly: parts preparation
For the following step please prepare:
Heatbed MK52 24V (1x)
Heatbed cable red (1x)
Heatbed cable black (1x)
M3x10 screw (2x)
M3w washer (2x)
M3nN nut (2x)

Step 3 Heatbed cable assembly (part 1)

Heatbed cable assembly (part 1)
Heatbed cable assembly (part 1)
Heatbed cable assembly (part 1)
IT IS IMPORTANT to connect the power cable correctly. Before you start the assembly have a look at the pins. The one on the left with "GND" sign must be connected to the BLACK WIRE.
Take both Heatbed cables. Note the label on each cable. For the following steps, prepare the ends of the cables without the label.

Step 4 Heatbed cable assembly (part 2)

Heatbed cable assembly (part 2)
Heatbed cable assembly (part 2)
Heatbed cable assembly (part 2)
Heatbed cable assembly (part 2)
Place the black wire above the pin with "GND" sign. Use the end of the cable that is not labeled with QR code. The QR code must be at the other end.
Place the M3w washer above the round cable connector.
Press the M3x10 screw through all parts.
Hold the screw and carefully turn the heatbed upside down.
Attach the M3nN nut onto the M3x10 screw and tighten it slightly.
Turn the heatbed back around. Using the universal wrench and the Allen key, tighten up the screw. We will adjust the cable position later on, therefore do not tighten the screw too firmly yet.

Step 5 Heatbed cable assembly (part 3)

Heatbed cable assembly (part 3)
Heatbed cable assembly (part 3)
Repeat this procedure for the second (Red / + / VCC) wire. Use the end of the cable that is not labeled with QR code. The QR code must be at the other end.
Before proceeding further, please check again that:
BLACK wire must be connected to the "GND"
RED wire must be connected to the "VCC"
The cable cover, which will be applied later requires the connectors to be slightly inclined towards each other. Press them gently, but leave a gap between them.
Now, tighten both screws firmly using the Allen key and the wrench. Maintain the position of the connectors while tightening.

Step 8 Assembling the heatbed-cable-cover: nylon filament

Assembling the heatbed-cable-cover: nylon filament
Assembling the heatbed-cable-cover: nylon filament
Assembling the heatbed-cable-cover: nylon filament
Assembling the heatbed-cable-cover: nylon filament
Place the heatbed-cable-cover-bottom like in the picture. Push the heatbed thermistor cable through the heatbed-cable-cover-bottom.
Insert the nylon filament into the hole in the heatbed-cable-cover-bottom. Don't let the nylon filament stick out too much on the other side. It should not protrude more than 2 millimeters.
When inserting the nylon filament, ensure that the filament does not damage the thermistor cables under the printed part.
Orient the curve of the filament as shown in the third picture.

Step 9 Assembling the heatbed-cable-cover-bottom

Assembling the heatbed-cable-cover-bottom
Assembling the heatbed-cable-cover-bottom
Assembling the heatbed-cable-cover-bottom
Slide the cable-cover-bottom under the heatbed cable connectors (M3nN nuts). See the correct orientation in the picture.
Secure the cover with the M3x10 screw from the top. Tighten the screw firmly.

Step 10 Assembling the heatbed-cable-cover-top

Assembling the heatbed-cable-cover-top
Assembling the heatbed-cable-cover-top
Assembling the heatbed-cable-cover-top
Assembling the heatbed-cable-cover-top
Wrap the end of the cable bundle together with the nylon filament in the textile sleeve. Slide the sleeve as far towards the heatbed as possible.
Attach the heatbed-cable-cover-top onto the junction and secure it with two M3x10 screws.
On the bottom side, leave a slack on the thermistor cable for one finger to be pushed through.
Make sure there is no big gap between both covers.

Step 12 Y-carriage variations

Y-carriage variations
Y-carriage variations
The Y-carriage has two variations, depending on which MK3 printer model you have. Each variant has a different assembly procedure. According to the picture distinguish your variation and follow the appropriation instructions:
NEW version: there are three pockets (recesses) for bearings in the Y-carriage. If you have this variation of the part, go to step Y-carriage: parts preparation (new).
OLD version: there are three cutouts for bearings in the Y-carriage. If you have this variation of the part, go to step Y-carriage: parts preparation (old).

Step 13 Y-carriage (old): parts preparation

Y-carriage (old): parts preparation
Y-carriage (old): parts preparation
LM8UU bearing (3x)
Y-carriage (1x)
Bearing clip (3x)
Rubber bearing pad 31x16x0.5 mm (3x)
M3x12 screw (6x)
Plastic bearing pad 31x16x1 mm (3x)
M3nN nut (6x)

Step 14 Y-carriage (old): parts preparation (lubricating)

Y-carriage (old): parts preparation (lubricating)
Y-carriage (old): parts preparation (lubricating)
Y-carriage (old): parts preparation (lubricating)
Y-carriage (old): parts preparation (lubricating)
For the following steps, please prepare:
Prusa lubricant applicator (1x)
Prusa lubricant (1x) for LM8UU bearings
Several paper towels to wipe oil and grease from the bearing surface.
Each bearing must be lubricated before mounting on the printer. Follow these instructions carefully.

Step 15 Lubricating the bearing (old)

Lubricating the bearing (old)
Lubricating the bearing (old)
Lubricating the bearing (old)
Lubricating the bearing (old)
Use any piece of fabric as a pad to protect your working surface from grease.
Make sure the bearing is clean inside. 
Wipe the preservative oil off the bearing surface with a paper towel.
It is necessary to lubricate all 4 rows of balls inside the bearing.
Open the lubricant and pierce the hole in the tube with the tip in the cap.
Screw the tube into the applicator.
Carefully slide the entire bearing onto the applicator.

Step 16 Lubricating the bearing (old)

Lubricating the bearing (old)
Lubricating the bearing (old)
Lubricating the bearing (old)
Lubricating the bearing (old)
Turn the tube and applicator counterclockwise until you feel a slight resistance. This means that the holes in the applicator are aligned with the ball rows.
Gently press the tube to push the lubricant into the ball rows of the bearing.
Look at the front of the bearing. When the applicator pushes the lubricant out (around the black gasket), stop pressing the tube. Hold the bearing with the other hand during the lubricating.
The grease must be spread evenly over all four ball rows inside the bearing. There must not be too much grease, or too little. Take a closer look at the last picture.
Wipe off excess grease on the outside of the bearing with a paper towel.
Use this procedure for all three bearings.
The bearings may leave excess grease on the smooth rods after their installation. Wipe off any residue with a paper towel.

Step 17 Assembling the bearing clips (old)

Assembling the bearing clips (old)
Assembling the bearing clips (old)
Push two M3x12 screws through the bearing clip.
Insert the rubber bearing pad on the screws.
Insert the plastic bearing pad on the screws.
Repeat the same for the remaining two bearing clips.
The order of the pads is crucial. Check the order on all three bearing clips.

Step 18 Installing the bearing on the Y-carriage (old)

Installing the bearing on the Y-carriage (old)
Installing the bearing on the Y-carriage (old)
Installing the bearing on the Y-carriage (old)
Installing the bearing on the Y-carriage (old)
Note the three cutouts for bearings in the Y-carriage.
Start with the side with the one pocket. Attach the bearing clip on the cutout.
From the opposite side, secure each screw with the M3nN nut. Do not tighten the nuts, 1-2 turns are enough for now.
Insert the bearing into the bearing clip.
If the bearing cannot be inserted easily, you have probably tightened the M3nN nuts too much, loosen them.

Step 19 Aligning the bearing (old)

Aligning the bearing (old)
Aligning the bearing (old)
Aligning the bearing (old)
Aligning the bearing (old)
The correct bearing orientation: When placing bearings onto the Y-carriage, make sure that they are oriented as shown in the picture. The tracks (rows of balls) have to be on the sides.
Align the bearing so that it is centered on the bearing clip. Approximately the same piece of bearing should be visible on each side.
Maintain the bearing position and slightly tighten both screws. Just barely to maintain its position and orientation. We will tighten the screws firmly later on.
Using the 2.5mm Allen key and the universal wrench, slightly tighten the M3nN nuts. Do not tighten it completely, just secure the bearing orientation and position. We will completely tighten it later.

Step 20 Installing the bearings on the Y-carriage (old)

Installing the bearings on the Y-carriage (old)
Installing the bearings on the Y-carriage (old)
Installing the bearings on the Y-carriage (old)
Installing the bearings on the Y-carriage (old)
Attach two bearing clips on the remaining two bearing pockets and push two bearings inside.
From the opposite side, secure each screw with the M3nN nut. Do not tighten the nuts, 1-2 turns are enough for now.
Orient both bearings so that the two rows of bearing balls have to be on the sides.
Unlike the previous bearing, position the bearings as close to the center of the Y-carriage as possible. Beware, the bearings must not touch the edge of the pocket!
Correct bearing alignment is CRUCIAL. Proceed carefully and make sure that both bearings are as close to the center of the Y-carriage as possible and do not touch any pocket edge.
Maintain the bearing's position and slightly tighten the screws. Just barely to maintain the position and orientation of the bearings. We will tighten the screws firmly later on.
Using the 2.5mm Allen key and the universal wrench, slightly tighten the M3nN nuts. Do not tighten it completely, just secure the bearing orientation and position. We will completely tighten it later.

Step 22 Inserting smooth rods into Y-carriage (old)

Inserting smooth rods into Y-carriage (old)
Inserting smooth rods into Y-carriage (old)
NOW, PLEASE BE VERY CAREFUL! Gently insert the rod straight into the bearings, do not apply too much force and do not tilt the rod!
In case you manage to push out some balls from the bearings by accident, please count the balls. Without one or two balls, the bearing will continue to work. If there are more of them, please consider ordering new bearings.
Carefully tighten the screws fully into the nuts on the underside. Make sure you tighten the screws EQUALLY and FIRMLY. Each screw must come all the way through the nut, or at least its tip must be aligned with the top surface of the nut.
After the final tightening, the movement of the smooth rods must be gentle. If the smooth rod moves stiffly, loosen the screws and repeat the procedure.
Now, please go to step Preparing Y-rod-holder.

Step 23 Y-carriage: parts preparation (new)

Y-carriage: parts preparation (new)
Y-carriage: parts preparation (new)
Y-carriage: parts preparation (new)
For the following steps, please prepare:
LM8UU bearing (3x)
Y-carriage (1x)
Bearing clip (3x)
Rubber bearing pad 31x16x0.5 mm (3x)
Plastic bearing pad 31x16x1 mm (3x)
M3x8 screw (6x)

Step 24 Y-carriage (new): parts preparation (lubricating)

Y-carriage (new): parts preparation (lubricating)
Y-carriage (new): parts preparation (lubricating)
Y-carriage (new): parts preparation (lubricating)
Y-carriage (new): parts preparation (lubricating)
For the following steps, please prepare:
Prusa lubricant applicator (1x)
Prusa lubricant (1x) for LM8UU bearings
Several paper towels to wipe oil and grease from the bearing surface.
Each bearing must be lubricated before mounting on the printer. Follow these instructions carefully.

Step 25 Lubricating the bearing (new)

Lubricating the bearing (new)
Lubricating the bearing (new)
Lubricating the bearing (new)
Lubricating the bearing (new)
Use any piece of fabric as a pad to protect your working surface from grease.
Make sure the bearing is clean inside.
Wipe the preservative oil off the bearing surface with a paper towel.
It is necessary to lubricate all 4 rows of balls inside the bearing.
Open the lubricant and pierce the hole in the tube with the tip in the cap.
Screw the tube into the applicator.
Carefully slide the entire bearing onto the applicator.

Step 26 Lubricating the bearing (new)

Lubricating the bearing (new)
Lubricating the bearing (new)
Lubricating the bearing (new)
Lubricating the bearing (new)
Turn the tube and applicator counterclockwise until you feel a slight resistance. This means that the holes in the applicator are aligned with the ball rows.
Gently press the tube to push the lubricant into the ball rows of the bearing.
Look at the front of the bearing. When the applicator pushes the lubricant out (around the black gasket), stop pressing the tube. Hold the bearing with the other hand during the lubricating.
The grease must be spread evenly over all four ball rows inside the bearing. There must not be too much grease, or too little. Take a closer look at the last picture.
Wipe off excess grease on the outside of the bearing with a paper towel.
Use this procedure for all three bearings.
The bearings may leave excess grease on the smooth rods after their installation. Wipe off any residue with a paper towel.

Step 27 Assembling the bearing clips (new)

Assembling the bearing clips (new)
Assembling the bearing clips (new)
Push two M3x8 screws through the bearing clip.
Insert the rubber bearing pad on the screws.
Insert the plastic bearing pad on the screws.
Repeat the same for the remaining two bearing clips.
The order of the pads is crucial. Check the order on all three bearing clips.

Step 29 Aligning the bearing (new)

Aligning the bearing (new)
Aligning the bearing (new)
Aligning the bearing (new)
Aligning the bearing (new)
The correct bearing orientation: When placing bearings onto the Y-carriage, make sure that they are oriented as shown in the picture. The tracks (rows of balls) have to be on the sides.
Align the bearing so that it is centered on the bearing clip. Approximately the same piece of bearing should be visible on each side.
Maintain the bearing position and slightly tighten both screws. Just barely to maintain its position and orientation. We will tighten the screws firmly later on.

Step 30 Installing the bearings on the Y-carriage (new)

Installing the bearings on the Y-carriage (new)
Installing the bearings on the Y-carriage (new)
Installing the bearings on the Y-carriage (new)
Installing the bearings on the Y-carriage (new)
Attach two bearing clips on the remaining two bearing pockets and push two bearings inside.
Orient both bearings so that the two rows of bearing balls have to be on the sides.
Unlike the previous bearing, position the bearings as close to the center of the Y-carriage as possible. Beware, the bearings must not touch the edge of the pocket!
Correct bearing alignment is CRUCIAL. Proceed carefully and make sure that both bearings are as close to the center of the Y-carriage as possible and do not touch any pocket edge.
Maintain the bearing's position and slightly tighten the screws. Just barely to maintain the position and orientation of the bearings. We will tighten the screws firmly later on.

Step 32 Inserting smooth rods into Y-carriage (new)

Inserting smooth rods into Y-carriage (new)
Inserting smooth rods into Y-carriage (new)
Using a paper towel, wipe the transport oil from the surface of the smooth rods.
NOW, PLEASE BE VERY CAREFUL! Gently insert the rod straight into the bearings, do not apply too much force and do not tilt the rod!
In case you manage to push out some balls from the bearings by accident, please count the balls. Without one or two balls, the bearing will continue to work. If there are more of them, please consider ordering new bearings.
Tighten the screws on each bearing clip.
After the final tightening, the movement of the smooth rods must be gentle. If the smooth rod moves stiffly, loosen the screws and repeat the procedure.

Step 33 Preparing Y-rod-holder

Preparing Y-rod-holder
Preparing Y-rod-holder
Preparing Y-rod-holder
Preparing Y-rod-holder
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.
Insert one M3nS nut from the side of the Y-rod-holder.
Ensure and adjust the alignment of each nut with the 2mm Allen key.
Repeat for the remaining Y-rod-holders.

Step 34 Mounting the Y-rod-holder parts

Mounting the Y-rod-holder parts
Mounting the Y-rod-holder parts
Mounting the Y-rod-holder parts
Push one of the Y-rod-holders onto the rod. Align the front surface of the plastic part with the flat surface of the rod.
Check the correct position of the Y-rod-holders. The screw hole must be facing up and towards the center of the Y-carriage (see the picture).
Repeat for the remaining Y-rod-holders.

Step 35 Installing the Y-carriage

Installing the Y-carriage
Installing the Y-carriage
Installing the Y-carriage
Installing the Y-carriage
Take the Y-carriage including smooth rods with rod holders and place them in YZ-frame. Make sure, that two bearings are on the left side (see the picture, there are two pairs of the screw holes on the left and one pair on the right).
Secure each Y-rod-holders and fix them with M3x10 screws on the front plate (the one with the longer extrusions). Tighten both screws equally, but not completely. We will tighten them fully later on.
Insert the M3x10 screw into the hole in each front holder and tighten them.
Secure the second pair of the Y-rod-holder with two M3x10 screws. Tighten both screws equally, but not completely. We will tighten them fully later on.
Insert the M3x10 screw into the hole in each rear holder and tighten it.
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 original position.

Step 36 Aligning the smooth rods

Aligning the smooth rods
Aligning the smooth rods
Aligning the smooth rods
Aligning the smooth rods
IMPORTANT: proper alignment of the smooth rods is crucial to reduce noise and overall friction.
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.

Step 37 Assembling the Y belt: parts preparation

Assembling the Y belt: parts preparation
Assembling the Y belt: parts preparation
Assembling the Y belt: parts preparation
Assembling the Y belt: parts preparation
For the following steps, please prepare:
The printed parts are not the same, take a closer look a compare both parts with each other.
Y-belt-tensioner (1x) with an oval hole
Y-belt-holder (1x) with a hexagonal hole 
M3x40 screw (1x)
M3x10 screw (4x)
M3nN nut (1x)
GT2-20 pulley (1x)
Pin H8 2.9x20 (1x)
Y belt (1x)

Step 38 Assembling the Y belt

Assembling the Y belt
Assembling the Y belt
Assembling the Y belt
Insert the M3nN nut all the way into the Y-belt-holder.
Use the screw pulling technique. Attach the M3nN nut on the tip of the M3x40 screw (a few turns are enough). Do not tighten the screw, pull the nut all the way into the Y-belt-holder. Don't forget to remove the M3x40 screw from the part and keep it aside for later use.

Step 39 Assembling the Y belt

Assembling the Y belt
Assembling the Y belt
Assembling the Y belt
Assembling the Y belt
Lean the printer onto the right side (the one with the PSU) to gain access to the bottom.
Push the pin into the pulley and center it.
Take one of the Y belt ends and push it into the Y-belt-holder. Note the orientation of the belt (teeth).
Secure it by inserting and tightening the M3x10 screw.

Step 40 Assembling the Y belt holder

Assembling the Y belt holder
Assembling the Y belt holder
Assembling the Y belt holder
Assembling the Y belt holder
Using the M3x10 screw, fix the Y-belt-holder to the Y-carriage. Use the left (rear) hole in the center part.
Guide the Y-axis belt around the Y-axis motor pulley. Make sure the belt is inside the frame, not under!
Take the free end of the Y belt guiding from the pulley and push it into the groove in the Y-belt-tensioner.
Secure it with the M3x10 screw.

Step 41 Assembling the Y belt tensioner

Assembling the Y belt tensioner
Assembling the Y belt tensioner
Assembling the Y belt tensioner
Take the free end of the belt and guide it around the GT2-20 pulley.
Insert the belt with the pulley into the Y-belt-idler on the rear of the front plate.
Push the pulley all the way inside the printed part and lightly pull on the belt to lock the pulley in place.

Step 42 Assembling the Y belt tensioner

Assembling the Y belt tensioner
Assembling the Y belt tensioner
Assembling the Y belt tensioner
Assembling the Y belt tensioner
Insert the M3x10 screw into the Y-belt-tensioner and try if the screw reaches the threaded hole in the Y-carriage when tensioning the belt.
If the screw does not reach the hole, it is necessary to remove the Y-belt-holder (the one already installed) and reposition the belt by one tooth in both printed parts - one tooth in each printed part will be vacant.
Attach the Y-belt-tensioner to the right (front) hole in the Y-carriage and secure it with the M3x10 screw. Do not overtighten the screw. We will adjust the exact position later on.
Insert the M3x40 screw into the Y-belt-tensioner and tighten it until the screw reaches the nut in the second part.

Step 43 Tensioning the Y belt

Tensioning the Y belt
Tensioning the Y belt
Tensioning the Y belt
Tensioning the Y belt
Move the Y-carriage all the way to the back. Using a finger on your left hand, push the belt down. A medium force should be needed to squish the belt until both the parts touch. Don't try to overstretch the belt as you might damage the printer.
You can change the belt tension by adjusting the long M3x40 screw on the bottom of the Y-carriage.
Tighten the screw to bring the parts closer together and increase the tension.
Release the screw to move the parts apart to
decrease the tension.
After you set the correct belt tension, tighten up the M3x10 screw on the bottom to fix the Y-belt-tensioner in place.

Step 44 Belt tension check

Belt tension check
Belt tension check
This step is recommended, but optional. If you don't have a phone at your disposal, continue to the next step. You can do this check later on.
To verify or fine-tune the X or Y-axis belt tension on your printer, visit prusa.io/belt-tuner and open up the webpage on your mobile device. Or using your phone, scan teh QR code in the picture.
Watch the instructional video on prusa.io/belt-tuner-video and fine-tune your Y belt tension, if required.
The belt tuner app was tested on multiple phones and should work across all most common phone manufacturers. However, in some rare cases it might not work as expected. Please state your brand and model in the comments below the step.

Step 45 Aligning the Y belt

Aligning the Y belt
Aligning the Y belt
Make sure that both the top and bottom parts of the belt are parallel (directly above each other).
If not, adjust the belt position. Release both screws on the pulley and slightly move with it, until you reach the best position.
Tighten both screws on the pulley.
Note: If you need to readjust the belt position, don't forget to check the belt tension once again.

Step 48 Installing the Expansion joints

Installing the Expansion joints
Installing the Expansion joints
Installing the Expansion joints
Installing the Expansion joints
The installation of the expansion joints needs to be done carefully. It is crucial for the correct functionality of the printer. Carefully read the instructions:
Slide the expansion joint from the side on the M3x6r screw.
Make sure the expansion joints are correctly oriented. There is a recess with approximately the same shape as the expansion joint. The joint must fit into the recess. See the second picture.
Some of the Y-carriages don't have the recesses, depending on the version of the printer model. Position the expansion joints according to the picture.
Maintain the position and tighten the M3x6r screw using the 2.0mm Allen key.
Proceed the same for the rest of the expansion joints.
OLD Y-CARRIAGE: On the old Y-carriage without the recesses, maintain the correct position and orientation of the expansion joint using the universal wrench while tightening.

Step 50 Attaching the heatbed

Attaching the heatbed
Attaching the heatbed
Attaching the heatbed
Attaching the heatbed
Place the spacer onto the Y-carriage and align it with the hole in the center.
Put the heatbed on the Y-carriage and secure it by the M3x14bT. Do not fully tighten the screw yet.
Insert the M3x4bT screws into the remaining holes in the heatbed. Do not fully tighten the screws yet.

Step 51 Tightening the heatbed

Tightening the heatbed
Tightening the heatbed
After all screws are in place, tighten them in the following sequence:
Center screw
First four screws (edges)
Last four screws (corners)
Tighten the screws gently, but firmly.