7. Y-carriage & Heatbed assembly

Relevant for:

MK4S MK3.9S

Last updated a day ago

Difficulty

Moderate

Steps

Available languages

Step 1 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

⬢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)

⬢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)

⬢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)

⬢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 6 Covering the heatbed cables: parts preparation

⬢For the following steps, please prepare:

⬢Nylon 2x380 mm (1x)

⬢heatbed-cable-cover-bottom

⬢heatbed-cable-cover-top

⬢M3x10 screw (3x)

⬢M3n nut (3x)

⬢Textile sleeve 5x350 (1x)

Step 7 Assembling the heatbed-cable-cover-bottom

⬢Insert three M3n nuts into the shaped openings in the heatbed-cable-cover-bottom.

Use the screw pulling technique.

Step 8 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.

⬢Bend the nylon filament slightly toward the cables. Be sure to maintain the correct curve orientation, as shown in the second and third pictures.

⬢Orient the curve of the filament as shown in the third picture.

Step 9 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.

Make sure the nylon filament is still bent upward as in the previous step.

Step 10 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 11 Wraping the textile sleeve

⬢Finish wrapping the cable bundle in the textile sleeve. And twist the sleeve, not the cables.

Step 12 Y-carriage versions

⬢The Y-carriage has two versions, depending on which MK3 printer model you have. Each version requires a different assembly procedure. Use the picture to identify your version and follow the corresponding 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 version, continue to the next step.

Step 13 Y-carriage (OLD): parts preparation

⬢LM8UU bearing (3x)

The bearings come pre-lubricated from our factory and do not require additional lubrication upon initial use.

⬢Y-carriage (1x)

⬢Bearing clip (3x)

⬢M3x12 screw (6x)

⬢Rubber bearing pad 31x16x1 mm (3x)

⬢Plastic bearing pad 31x16x0.5 mm (3x)

⬢M3nN nut (6x)

Step 14 Bearing clip assembly (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 15 Bearing installation (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 16 Bearing alignment (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 17 Bearing attachment (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.

Step 18 Smooth rods: parts preparation (OLD)

⬢For the following steps, please prepare:

⬢Y-rod-holder (4x)

⬢M3x10 screw (12x)

⬢M3nS nut (12x)

⬢Smooth rod 8x330 (2x)

Step 19 Inserting smooth rods (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 continue to step Preparing Y-rod-holder.

Step 20 Y-carriage: parts preparation (NEW)

These steps are valid only if you have the NEW version of the Y-carriage.

⬢For the following steps, please prepare:

⬢LM8UU bearing (3x)

The bearings come pre-lubricated from our factory and do not require additional lubrication upon initial use.

⬢Y-carriage (1x)

⬢Bearing clip (3x)

⬢Rubber bearing pad 31x16x1 mm (3x)

⬢Plastic bearing pad 31x16x0.5 mm (3x)

⬢M3x8 screw (6x)

Step 21 Bearing clip assembly (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 22 Bearing alignment (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 in the corners.

⬢Align the bearing so that it is centered in the bearing clip. Approximately the same amount of bearing should be visible on each side.

⬢Maintain the bearing position and slightly tighten both screws. Just enough to maintain the bearing’s position and orientation. You will tighten the screws firmly later on.

Step 23 Bearing installation (NEW)

⬢Note the three pockets for bearings in the Y-carriage.

⬢Start with the side with the one pocket. Attach the bearing clip on the cutout.

⬢Insert the bearing into the bearing clip.

Step 24 Bearing attachment (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.

Step 25 Bearings positioning (NEW)

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.

⬢Unlike the previous single-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!

Incorrect positioning: the bearings must not touch or overlap the edges of the pocket as shown in the bottom of the first picture.

⬢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.

⬢After securing the clips double-check the correct position of the bearings so that they do not touch the edges of the pockets.

Step 26 Smooth rods: parts preparation (NEW)

⬢For the following steps, please prepare:

⬢Y-rod-holder (4x)

⬢M3x10 screw (12x)

⬢M3nS nut (12x)

⬢Smooth rod 8x330 (2x)

Step 27 Inserting smooth rods (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!

⬢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.

⬢After tightening all the screws securing the bearing clips, make a final check of the correct position of the bearings:

Two-bearing side: the bearing must be positioned closer to the center of the Y-carriage. It must not touch or extend over the edge of the pocket.

⬢Single-bearing side: the bearing must be in the center of the pocket.

Step 28 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 29 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 30 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 31 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 32 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 33 Assembling the Y-belt-holder

⬢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 34 Assembling the Y belt

⬢Lean the printer onto the right side (the one with the PSU) to gain access to the bottom.

⬢Insert the M3x10 screw through the hole in the Y-belt-holder.

⬢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 35 Attaching 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.

Tip: pre-screw the screw into the Y-belt-holder before attaching it to the Y-carriage.

⬢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 36 Assembling the Y belt tensioner

⬢Push the pin into the pulley and center it.

⬢Take the Y-belt-tensioner with the belt and guide the belt 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 37 Attaching the Y belt tensioner

⬢Insert the M3x10 screw into the Y-belt-tensioner and 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.

If the screw does not reach the hole in the Y-carriage, 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.

⬢Insert the M3x40 screw into the Y-belt-tensioner and tighten it until the screw reaches the nut in the second part.

Step 38 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 39 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 the 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 40 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.

Step 41 Expansion joints: parts preparation

⬢For the following steps, please prepare:

⬢Expansion joint (8x)

⬢M3x6r screw (8x)

Step 42 Expansion joints preparation

⬢Install eight M3x6r screws in the outer holes on the Y-carriage. Do not tighten them completely. A few turns are enough for now.

Step 43 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.

For the OLD Y-carriage without recesses, maintain the correct position and orientation of the expansion joint using the universal wrench while tightening!

Step 44 Attaching the heatbed: parts preparation

⬢For the following steps, please prepare:

⬢M3x4bT screw (8x)

⬢M3x14bT screw (1x)

⬢Spacer 6x3.1x8 mm (1x)

Step 45 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 46 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.

Step 47 Guiding the heatbed cables: parts preparation

⬢For the following steps, please prepare:

⬢MK4S-Wifi-cover (1x)

⬢ESP-WiFi (1x)

⬢M3x12 screw (3x)

⬢Power terminal screw 6/32" (2x)

Step 48 Assembling the Wi-Fi

⬢Insert the ESP-WiFi module into the WiFi-cover, positioning it just below the bridge on the left side.

⬢On the other side, ensure the connector fits correctly into the hole in the cover.

⬢Set the assembly aside for a while.

Step 49 Guiding the heatbed cables

⬢Push the heatbed cables and heatbed thermistor cable through the square opening on the back of the xBuddy Box.

⬢Push the filament through the circle hole right below the square opening.

⬢Place the black heatbed cable on the left terminal and secure it with the terminal screw.

⬢Place the red heatbed cable on the right terminal and secure it with the terminal screw.

⬢Connect the heatbed thermistor cable to the xBuddy board.

Step 50 Installing the WiFi cover assembly

Be very careful when handling and connecting the ESP module to avoid bending and damaging the pins.

⬢Take the WiFi cover assembly and connect the ESP module pins to the connector in the xBuddy.

⬢Position the heatbed cable bundle into the cutout in the WiFi cover.

⬢Close the WiFi cover carefully, ensuring the pins of the ESP module are properly engaged in the connector on the xBuddy.

Double-check that the heatbed cable bundle is in place.

⬢Secure the cover with three M3x12 screws.

Step 51 NFC antenna: parts preparation I.

⬢For the following steps, please prepare:

⬢xBuddybox-cover (1x)

⬢El-box-cover (1x)

⬢M3x6 screw (4x)

⬢M3x10 screw (2x)

The list continues in the next step ...

Step 52 NFC antenna: parts preparation II.

⬢NFCcoil (1x)

⬢Isopropyl Alcohol (IPA) Cleaning pad (1x)

⬢Adhesive film 32 x 25 mm (1x)

⬢NFC coil cable (1x)

Step 53 Connecting the NFC antenna

⬢Locate the small round connector labeled NFC on the bottom left side of the xBuddy board.

⬢Connect the NFC coil cable to the board by fitting the connectors together and pressing lightly until you feel a click, ensuring a correct connection.

Ensure the NFC antenna cable connector is securely plugged in and does not come loose from the board.

BE EXTRA CAREFUL when connecting the NFC antenna cable connector. Excessive pressure or misalignment can cause irreversible damage.

⬢Leave the other end of the cable free for now.

Step 54 Preparing the NFCcoil

⬢Using the IPA cleaning pad, wipe off any grease from the "underside" of the NFCcoil. The side without the company logo.

Avoid covering the holes in the NFCcoil board.

⬢Peel off the yellow protective film from the adhesive tape.

Attention: There is a self-adhesive layer on the antenna.

⬢Stick the adhesive film on the cleaned side of the NFCcoil approximately as shown. The side without the company logo.

Do not put the the adhesive tape over any holes in the board!

Step 55 Assembling the NFC antenna

⬢Peel of the adhesive tape paper layer from the NFCcoil.

⬢Stick the NFCcoil on the inner side of the El-box-cover approximately like in the picture. See the correct orientation of both parts!

⬢Leave at least 2mm space between the NFCcoil end the edge of the El-box-cover.

⬢Locate the small round connector on the NFCcoil.

⬢Connect the NFC coil cable to the board by fitting the connectors together and pressing lightly until you feel a click, ensuring a correct connection.

Ensure the NFC antenna cable connector is securely plugged in and does not come loose from the board.

BE EXTRA CAREFUL when connecting the NFC antenna cable connector. Excessive pressure or misalignment can cause irreversible damage.

Step 56 Verify all connections once more!

⬢Check your electronics connection with the first picture.

Before covering the electronics, check and compare your wiring.

⬢Compare your cable management with the third picture.

Make sure that all connectors are fully inserted and PSU cables properly tightened. Otherwise, there is a risk of damage to the printer!

Step 57 Covering the xBuddy box: bottom cover

⬢Push two M3x10 screws through the El-box-cover.

⬢Attach the cover to the xBuddy Box. There are two threaded holes in the xBuddy box. Make sure there is no cable in the way for the screws and the cover.

⬢Secure the el-box-cover by tightening both M3x10 screws to the xBuddy box.

Step 58 Covering the xBuddy box

⬢Guide the NFC antenna cable to the rightmost side as shown.

Avoid routing the cable over the Ethernet connector on the left and the power cables on the right, or it may get pinched and damaged when covering the electronics box.

⬢Carefully cover the xBuddy box by first sliding the bent part of the cover into the box.

Avoid pinching the cables. Double-check the NFC antenna cable position.

⬢Align the xBuddy box cover with the xBuddy box and secure it with four M3x6 screws.