1. Needle-nose pliers for the heatbed assembly
    • Needle-nose pliers for the heatbed assembly

    • 2.5mm Allen key for M3 screws

    • 2mm Allen key for heatbed alignment

  2. For the following step please prepare: Heatbed MK52 24V (1x)
    • For the following step please prepare:

    • Heatbed MK52 24V (1x)

    • Power cable (1x)

    • M3x10 screw (2x)

    • M3/3,2/9/0,8 washer (2x)

    • M3nN nylock nut (2x)

    • IT IS VERY 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.

    Can’t seem to find the washers, they weren’t in the psu and hb bag, and I don’t think they’re in the spare bag either.

    Shane Hobson - Reply

    Hi,

    Please check the 9. Spare Bag with spare parts. The washers should be there. In case of missing washers or other problems, please contact our technical support on email info@prusa3d.com.

    Martini H. - Official Prusa CS -

    Nevermind the 3rd shop I went to had them lol.

    Shane Hobson -

  3. Place the black wire above the pin with "GND" sign. Make sure you are using the rounded connector. Place the washer above the rounded cable connector. Press the M3x10 screw through all parts.
    • Place the black wire above the pin with "GND" sign. Make sure you are using the rounded connector.

    • Place the washer above the rounded cable connector.

    • Press the M3x10 screw through all parts.

    • Hold the screw and carefully turn the heatbed upside down.

    • Place the M3nN nut on the top of the M3 screw and tighten it slightly.

    • Turn the heatbed back, using pliers and Allen key tighten the screw. We need to adjust cable position in the next step, therefore do not tighten the screw too firmly.

    • Repeat this procedure for the second (red) wire.

    A 7/32” socket works for the Nyloc nuts

    Steve Lionel - Reply

  4. Before proceeding further, please check again the cable is connected correctly to the heatbed. BLACK wire must be connected to the "GND" RED wire must be connected to the "VCC"
    • Before proceeding further, please check again the cable is connected correctly to the heatbed.

    • 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.

    • Design of your heatbed might slightly differ from the last picture.

    • Now, tighten both screws using the Allen key and the pliers.

  5. For the following steps, please prepare:
    • For the following steps, please prepare:

    • Heatbed MK52 (1x)

    • Textile sleeve 5 x 300 mm (1x)

    • M3n nut (3x)

    • M3x10 screw (3x)

    • Heatbed-cable-cover (2x)

    I don’t know what I actually have, but you say that the textile sleeve is “6 x 300mm” here; the label on the tube they came in says I got “2x5x300” (along with the “1x13x490” one we already used on the extruder bundle). (I had no problem doing the steps below, though!)

    Bryan Stearns - Reply

    Hey Bryan, good catch. We’ll fix it shortly.

    Filip M - Official Prusa CS -

    Minor notes:

    1. Showing the nuts and screws on the black heatbed isn’t as visually effective as showing them against a white background (as is normally done).

    2. The figure shows the heatbed cable cover and cable clip but the text only refers to the cable cover.

    Scott Mutton - Reply

    Hey Scott, good catch. We’ll fix it asap.

    Filip M - Official Prusa CS -

  6. Insert M3n nuts in the printed part. In case you can't press the M3n nut in, don't use excessive force. Take the M3 bolt and  thread it from the opposite side of the printed part, as you tighten the screw, it will pull the nut in. Be careful not the break the printed part during tightening. In case the power cable is fixed by screws (not soldered) the heatbed-cable-cover slightly differs from the picture, but the following assembly process is identical.
    • Insert M3n nuts in the printed part.

    • In case you can't press the M3n nut in, don't use excessive force. Take the M3 bolt and thread it from the opposite side of the printed part, as you tighten the screw, it will pull the nut in. Be careful not the break the printed part during tightening.

    • In case the power cable is fixed by screws (not soldered) the heatbed-cable-cover slightly differs from the picture, but the following assembly process is identical.

    The red bullet point sounds exactly like Josef’s screw pulling technique but I don’t see his avatar… :-)

    Miguel Barroso - Reply

    @Miguel - I thought the exact same thing! This is the “Josef Prusa method” and they missed his icon.

    Michael Pennachio - Reply

    Sorry guys :) Well, you’ll have many other occasions to see the avatar :)

    Martin L. - Official Prusa CS -

  7. Place the heatbed-cable-cover on the heatbed to cover the soldered cables and LED. Tighten the cover to the heatbed using M3x10 screw and Allen key. Be careful not to pinch (break) any wires from the heatbed!
    • Place the heatbed-cable-cover on the heatbed to cover the soldered cables and LED.

    • Tighten the cover to the heatbed using M3x10 screw and Allen key. Be careful not to pinch (break) any wires from the heatbed!

    This screw was sticking out the other side well past the nut and was interfering with the hotend wires.

    I added a spare nut under the head as a spacer and that solved my problem.

    I double checked to make sure I used the correct screw and I can’t quite see how far it sticks out in the picture for Step 11.

    John Merling - Reply

    Hey John,

    There is no need to add the spacer. The screw can protrude on top of the cover.

    Filip M - Official Prusa CS -

    I had the same problem, it has been discussed here:

    https://shop.prusa3d.com/forum/assembly-...

    Mattias Ernelli -

    It is a problem, looking at that thread, it looks like some of the hotend wires have plenty of room and some, like mine, don’t.

    A note should be added to specifically check the clearance in the back left corner to make sure everything is OK.

    John Merling -

    Hey guys, thanks for pointing this out, we will try look into it.

    Martin L. - Official Prusa CS -

    I came here specifically to add the same suggestion that John Merling added above about adding a spacer to prevent the protruding M3x10. During normal operations, this isn’t an issue, but during the Calibrate XYZ process, on the last registration point this protruding M3x10 can rub the insulation of the hotend power cable(s). Not only will this disturb the XYZ calibration results, but, over time can lead to exposed wires from the hotend.

    I did not have this issue directly after the initial build (AFAICT), but I noticed the rubbing and the damaged insulation after recalibrating a week later. My solution was the same as John’s and, in fact, I came here to see if I missed that instruction initially.

    Regardless of what Filip M says, I recommend adding it. You likely have the spare nut, you could avoid a possible dangerous situation later, and it looks better, IMO.

    Thank you, Prusa, for looking into this. I definitely needs attention.

    mkoistinen@gmail.com -

    Hello guys,

    thanks for the feedback. We are working on the solution.

    Martini H. - Official Prusa CS -

    great suggestion sir! I added a spare m3ns here and everything lines up nicely on top and bottom sides!

    Scruff -

    Thanks guys, excellent watch-out and good suggestion!

    Stephan Lindeque -

    The plastic on the crimped on ring terminals was much too obtrusive. It did not come even close to fitting inside the cover. I had to cut the sleeve off of one of them to make it work.

    Cal - Reply

    Hey Cal,

    There is no need to cut the plastic crimp. All you need to do is “push” both wires together, so they don’t block the plastic part.

    Filip M - Official Prusa CS -

    I was not cautious and didn’t connect with the third image and instruction on Step 4. ensuring to angle the connectors before tightening works, it’s snug, but you can make it match up.

    Brian S -

    Also, in the picture, where are the nuts used to bolt on the wire terminals? Should the bolts be sticking through the board right there?

    Cal - Reply

    Hey Cal,

    Make sure to read all the step notes and check all the pictures - everything is explained there.

    The nuts do not interfere with both terminal screws.

    Filip M - Official Prusa CS -

    The second picture here does not illustrate the correct part.

    Jonny Badley - Reply

    Hey John,

    The second picture only acts as a guide where to add the screw.

    Filip M - Official Prusa CS -

    I had the same problem as others with the protruding screw damaging the insulation of the extruder cable and failing XYZ calibration.  I found this was because my cable from the extruder was not lying in the groove behind the extruder, see step 64 of E-axis assembly.  When corrected the wiring was no where near the screw

    Roy Steiner - Reply

    As it is mentioned later on in this chapter (step 17), if you have an M3x8mm anywhere near you, use it here. It will fit perfectly and flush with the nut and avoid any possible contact with the print head when it is up in that corner.

    Ken Robertson - Reply

    I agree that an M3x8 is the correct screw to use here. Good thing I had one around.

    Steve Lionel - Reply

    If you can’t find an M3x8 screw, you could also use a small Dremel tool to shorten the M3x10. I found this to be better than using an extra nut as a spacer because the heatbed-cable-cover still rubbed up against the extruder’s wires (altho not as damaging as the screw end itself). Don’t forget protective eyewear if you choose to do this as well!

    Fabrique Mobile de l'Outaouais - Reply

  8. Do not stretch the black/white thermistor cable, leave some slack under the heatbed, so when the heatbed moves during print, the cable won't get stretched resulting in disconnection from the centre of the heatbed. However, the slack shouldn't be causing the cable to sag down more than few millimetres. Otherwise, the cable might rub against the printer's frame and damage itself! Turn the heatbed upside-down to check this. Guide the black thermistor cable next to the heatbed heater cable and wrap it few times around (see the photo).
    • Do not stretch the black/white thermistor cable, leave some slack under the heatbed, so when the heatbed moves during print, the cable won't get stretched resulting in disconnection from the centre of the heatbed.

    • However, the slack shouldn't be causing the cable to sag down more than few millimetres. Otherwise, the cable might rub against the printer's frame and damage itself! Turn the heatbed upside-down to check this.

    • Guide the black thermistor cable next to the heatbed heater cable and wrap it few times around (see the photo).

    • The thermistor cable is in black or white colour, their functionality is the same.

    Parts provided in the kit does not match the picture, there is no channel for thermistor cable,instead you put the thermistor cable under the heated bed cover, please rectify.

    Marcel Etienne Bergeron - Reply

    Hey Marc, which channel are you referring to?

    Filip M - Official Prusa CS -

    If we have three screws instead of one, should we route the thermistor wire between two of the screws, or around all three screws?

    Dan Green - Reply

    Hello Dan, everybody has 3 screws, it’s just that at this point, only one should be in this plastic part. Please look closely at the photos and adjust the cable accordingly.

    Martin L. - Official Prusa CS -

    It was difficult to tell from the description how much slack to leave in the thermistor wire. A photo illustrating the upside-down view might be helpful.

    Laurel W - Reply

    Hey Laurel,

    The second picture shows exactly how much slack should be left.

    Filip M - Official Prusa CS -

    I think Laurel W is referring to a “Z height” view to see how much the cable sags off the heated bed as opposed to a sideways bend along the plate itself. A picture from a finished printer’s underside near the area where the cables connect would do the trick.

    Fabrique Mobile de l'Outaouais -

    Hello,

    that’s because the cable shall not sag off at all. “Sideways bend” only. :)

    Martin L. - Official Prusa CS -

  9. Use the textile sleeve and wrap the cables from the heatbed. Start by few centimeters of the sleeve behind the heatbed cover. When the first "wrap" is ready, slide it inside the heatbed cover. Ensure it is at least 5-6 mm.
    • Use the textile sleeve and wrap the cables from the heatbed. Start by few centimeters of the sleeve behind the heatbed cover.

    • When the first "wrap" is ready, slide it inside the heatbed cover. Ensure it is at least 5-6 mm.

    • Before you continue with wrapping the sleeve, we need to fix it in the cable cover. Please proceed to the next step.

    This picture does not illustrate the correct part. There is not enough room to sandwich the sleeve in the cable cover. I used a cable tie gently round the sleeve right beside the cable cover.

    Jonny Badley - Reply

    Hey Johny,

    If you can’t fit the sleeve, then perhaps you haven’t twisted it enough. Make sure you do the similar thing like with extruder cable bundle.

    Filip M - Official Prusa CS -

  10. Place second part of the cover on the top of the  textile sleeve. Make sure the thermistor cable is in the middle going through a cutout in the printed part!!! Otherwise, you will pinch and possibly break the cable!!! Insert two screws M3x10 and tighten them, proceed with caution and tighten both screws equally.
    • Place second part of the cover on the top of the textile sleeve.

    • Make sure the thermistor cable is in the middle going through a cutout in the printed part!!! Otherwise, you will pinch and possibly break the cable!!!

    • Insert two screws M3x10 and tighten them, proceed with caution and tighten both screws equally.

    • Don't tighten the screw completely on one side and then on the other (see the second picture)!

    • Your tightened cover should look like the last picture.

  11. Now, finish wrapping the cable into the textile sleeve.
    • Now, finish wrapping the cable into the textile sleeve.

    • When done, slightly twist the sleeve (not the cables inside). The sleeve will evenly wrap all around the cable bundle.

  12. For the following steps, please prepare:
    • For the following steps, please prepare:

    • M3x14b screw (9x) / M3x12b screw (9x)

    • Due to update in manufacturing process, your kit might come with 12mm screws instead of 14 mm. Functionality remains unchanged.

    • 6x6x3t spacer (9x)

  13. Push the Y-carriage to the front and place the Heatbed behind. Locate a hole in the centre of the Y-carriage. Place one spacer on the top of the hole.
    • Push the Y-carriage to the front and place the Heatbed behind.

    • Locate a hole in the centre of the Y-carriage.

    • Place one spacer on the top of the hole.

    • The exact position of the spacer will be adjusted in the next step.

    If you change that screw that holds the cover from below to a shorter. Then it will not scratch my extruder cable as it did on mine

    Henrik J. Koch - Reply

    Hi Henrik. The extruder cable shall not touch this part at all.

    Martin L. - Official Prusa CS -

    Locate a hole the centre of the Y-carriage.’

    “Locate a hole on the centre of the Y-carriage” or,

    “Locate the hole on the centre of the Y-carriage” would be more correct…

    Miguel Barroso - Reply

    Hello Miguel, thank you! We’ll correct it.

    Martin L. - Official Prusa CS -

  14. Push the Allen key through the middle hole on the Heatbed and place it above the spacer. Use the Allen key to align all parts. After the alignment insert the M3x12b(14b) screw instead. Tighten the screw just slightly.
    • Push the Allen key through the middle hole on the Heatbed and place it above the spacer. Use the Allen key to align all parts.

    • After the alignment insert the M3x12b(14b) screw instead.

    • Tighten the screw just slightly.

    You can also use the filament from earlier to align the bed, spacer and plate. I found that easier to do.

    Ken biles - Reply

    make sure it’s one of the smaller Allen keys

    Alan Ostroff - Reply

  15. Move to the right side of the heatbed. Place another spacer with the pliers. Push the pliers between the heatbed and the Y-carriage.
    • Move to the right side of the heatbed.

    • Place another spacer with the pliers.

    • Push the pliers between the heatbed and the Y-carriage.

    • Use the Allen key to align the spacer.

    • After the alignment insert the screw instead and tighten it slightly.

    The center screw is the hardest. Once you have that in, the bed can only spin. Aligning the other spacers and screws gets easier as you go.

    Ken biles - Reply

    Tell me about it fiddly little fenacker aint it lol.

    Shane Hobson -

    I found that shining a bright light under the frame made lining up the spacers quite simple, if a bit awkward.

    Bruce Shipman - Reply

    +1 to using a flashlight or something. This is what I did:

    Grab a spacer with the pliers oriented correctly.

    Lift the bed with one hand while sliding the spacer in under it, looking from the top of the bed so can see when the hole of the bed lines up with the hole of the spacer. Just enough to get it close, doesn’t have to be perfectly lined up.

    Use an Allen key to properly line up the spacer and the hole in the bed with the hole in the mount. The Allen key should pretty much drop straight through.

    Using a flashlight or something, confirm the Allen key is through both the spacer and the bed frame (and not along the side or something).

    Carefully remove Allen key by pushing on it from below.

    Drop the screw in and slightly tighten.

    That method worked for me and it went much easier after doing the center hole first.

    Michael Pennachio -

  16. Using pliers insert spacers and screw into the remaining holes. DON'T fully tighten the screws. After all screws are in place, tighten them in the following order:
    • Using pliers insert spacers and screw into the remaining holes. DON'T fully tighten the screws.

    • After all screws are in place, tighten them in the following order:

    • Center screw

    • First four screws (edges)

    • Last four screws (corners)

    During troubleshooting, I realized that I had missed one of the spacers and it ended up sticking to a magnet under the heatbed.

    I discovered it when I was on the chat and he had me check to make sure all of the screws were tight, that one wasn’t because the spacer was gone.

    John Merling - Reply

    I actually had some success placing all 9 spacers and then carefully lowering the entire heat bed (with screws in their holes) down , starting from the back and kind of moving things into place as I dropped it down. Worth a try if you’re daring and have a steady hand.

    Nick Gawel - Reply

    Another screw missing

    Gavin - Reply

    I have lost one spacer because I dropped it and can’t find it anymore, what should I do?

    Jakob Horak - Reply

    Alright so I resolved the issue by getting help and together with my sister I finally found it, but I’m going to leave the comment so that someone else who has this problem too can find the answer without waiting.

    Jakob Horak -

    I found that after aligning the spacer using the pliers and allen wrench and then GENTLY pinching the spacer between the bed and the frame underneath helps to hold the spacer in place, making it easy to insert the screw and get it started. Without the pressure the spacer has a tendency to slide around. This works well on all but the center spacer.

    Doug Fleming - Reply

  17. Let's make sure the cables from the hotend aren't in contact with the heatbed.
    • Let's make sure the cables from the hotend aren't in contact with the heatbed.

    • By rotating the threaded rods at the same time, lower manually the X-axis down until the nozzle is almost touching the heatbed.

    • In case the P.I.N.D.A. sensor touches the bed before the nozzle, move it up slightly.

    • Ensure there is a gap between the screw in the heatbed and the surface of the hotend cables. The gap should be 2-3 millimetres, the steel sheet will add another 1 mm.

    • In case the cables are rubbing against the screw, adjust them (push them up in the extruder)

    I cheated…used a spare M3x8mm to replace the manual intended M3x10 — makes the whole unit held in place with flush screws! (I’m referring to STEP 7; replaced the M3x10mm with my spare M3x8mm)

    Mark L - Reply

    I didn’t like how close mine was, so I swapped out the M3x10 for an M3x8 button head I already had. Just makes far more sense.

    Ken Robertson -

    You're not the only one mark, I checked mine two millimeters

    Pascal Robert - Reply

    are we just suppose to be concerned about the hot end cables rubbing the screw? Or should I also be concerned about the cables/zip ties, rubbing the heatbed cable cover?

    Gage - Reply

    Hey Gage,

    Make sure you have assembled everything according to the manual - in this case nothing should be rubbing anything.

    Filip M - Official Prusa CS -

    I also wanted to be on the safe side with this. Didn’t have a spare M3x8mm screw, so I first added an extra M3 nut on the screw (all the way to the head, kind of functioning as a big washer), which was just enough to keep the end of the screw coming out on the other side. Looks also better compared with the other two screws in the cable holder.

    DennisB88 - Reply

    the m3 10mm screw as too close for comfort. I changed it to m3 8mm. I think an 8mm screw is optimal here.

    Paco - Reply

    Not to pile on, but totally agree with using the shorter 8mm screw. Luckily I had a m3 kit on me :)

    Paul alvarez - Reply

    Hello Paul (and everyone above) :)

    Thank you for the feedback, we’ll look into swapping it for 8mm screw.

    Marcin M. - Official Prusa CS -

    For the folks like me who have to build this an hour at a time, and are brand new to 3D printing, it would be nice to have a reminder on this step how to lower the X axis.

    Andrew VanHeuklon - Reply

    Hello Andrew,

    Thank you for the suggestion, we will look into including this information.

    Marcin M. - Official Prusa CS -

    I used a spare nut as a spaceraccording to advice above, since I didn’t have an extra screw of the right size. I am glad I did. Even though I put the hotend cables in the available channel, I would not have had enough room otherwise.

    Laurel W - Reply

    My lower print-head cables were rubbing here.

    I had to add an extra cable tie near the print head, around everything, an extra lower slot would have been nice here:

    https://d17kynu4zpq5hy.cloudfront.net/ig...

    vpkirk - Reply

    Being a Canadian, I didn’t have metric screws lying around… So what I did is screw one 10 mm into a spare frame hole then saw the excess. Be careful as I chipped a bit my frame =( Prusa really need to use 8 mm screw!!

    Lucas Rakoto-Sam - Reply

  18. For the following steps, please prepare:
    • For the following steps, please prepare:

    • 24V Power supply with cover (1x)

    • M4x10r screw with dome head (2x)

    • Make sure you are using M4 screws, different screws might cause issues!!!

    • M3x10 screw (2x)

    • The PSU switches between 110 V and 220 V automatically.

    You might want to remove the spaces after the “110” and “220” above — it causes 220V (for example) to word-wrap in the middle.

    Mark Wheadon - Reply

  19. Locate four mounting points on the YZ frame. Place the PSU on the frame and secure it with the M4x10r screws. Don't tighten them completely.
    • Locate four mounting points on the YZ frame.

    • Place the PSU on the frame and secure it with the M4x10r screws. Don't tighten them completely.

  20. Slide the PSU holders under the PSU cover. Secure the PSU with two M3x10 screws. Don't tighten them completely. You want  to be able to move the PSU on the mount to properly line up the other mount. Re-seat the PSU and then tighten all four screws.
    • Slide the PSU holders under the PSU cover.

    • Secure the PSU with two M3x10 screws. Don't tighten them completely. You want to be able to move the PSU on the mount to properly line up the other mount.

    • Re-seat the PSU and then tighten all four screws.

    To properly line up what other mount?

    ryman1 - Reply

    The PSU mounting holes.

    Filip M - Official Prusa CS -

    There should really be some sort of a spacer added under the power supply unit between the printed base and the PSU holders when tightening the M3x10 screws. The printed part warps into the bottom frame of the printer since there is space between it and the PSU holders, and you can’t completely secure the unit without doing so.

    Erik Diehl - Reply

    Hey Erik,

    Make sure you don’t overtighten it. That part shouldn’t warp, as it’s a thick piece of PETG.

    Filip M - Official Prusa CS -

  21. Slightly harder chapter, but have 10 %. We need to keep more for the next.
    • Slightly harder chapter, but have 10 %. We need to keep more for the next.

  22. You're getting closer! Just one more chapter and the assembly is done!
    • You're getting closer! Just one more chapter and the assembly is done!

    • Check the final look, compare it to the picture.

    • Don't place the steel sheet on the heatbed yet. Wait for the instructions in the Wizard during the calibration process.

    • Ready for the last assembly part? 8. Electronics assembly

Finish Line

246 other people completed this guide.

Jakub Dolezal

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