Needle-nose pliers for NYLON trimming.
  • Needle-nose pliers for NYLON trimming.

  • 2.5mm Allen key for M3 screws

  • 2mm Allen key for heatbed alignment

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Starting mid of January 2018 we are shipping redesigned heatbed cable cover. See the picture to recognize your version and then select from the following:
  • Starting mid of January 2018 we are shipping redesigned heatbed cable cover. See the picture to recognize your version and then select from the following:

  • New design: start with the Step 3

  • Old design: start with the Step 11

  • Extra fasteners needed for the redesigned heatbed cable cover are included with the printed part.

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

  • Heatbed MK52 (1x)

  • Spiral wrap (1x)

  • There are two spiral wraps remaining, use the bigger (thicker) one. You have to fit inside more cables now.

  • M3n nut (3x)

  • M3x10 screw (3x)

  • Heatbed-cable-cover (1x)

  • NYLON filament 30cm (1x)

There were only 2x M3n nut + 2x M3x10 screw in the bag with the cover. (Stil had one of both left from previous steps, so all was fine.)

Orne Brocaar - Reply

…ditto. Got the new printed cover parts, but the old cover’s hardware bag. Time to open up the spares. (My MK3 received 01/26)

Robert Wallace -

Please use the spare parts bag ;)

Jakub Dolezal -

wasn’t the spiral flex changes to something else? I read something on Prusa blog on the shop webpage?

Henrik J. Koch - Reply

Hi Henrik, yes there will be change, we are just finishing the redesign. The manual will be changed as soon as the we complete all the tasks.

Jakub Dolezal -

On the blog Josef said “The easiest remedy is to remove the spiral wrap and nylon filament from the heatbed wires, which completely prevents this from happening.” (https://www.prusaprinters.org/original-p...) Does this mean we should pretty much skip almost all steps in this chapter?

Bas - Reply

For this step please use the shorter one and DON'T TRIM it! Using the pliers cut one end of the filament to create a tip. Check the tip is similar to the third picture.
  • For this step please use the shorter one and DON'T TRIM it!

  • Using the pliers cut one end of the filament to create a tip.

  • Check the tip is similar to the third picture.

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Push the filament in the hole in the heatbed-cable-cover.
  • Push the filament in the hole in the heatbed-cable-cover.

  • BE EXTREMELY CAREFUL as the pliers tends to slide and you can easily harm yourself or break the printed part!!!

  • To make your assembly easier, check the filament is curved up (as in the picture).

  • If you have issues, try to adjust the tip on the NYLON filament.

Is there any benefit to using some glue between the filament and the cable cover? Reason I ask is because a true strain relief should be able to take a hit or tug and not pull out. If so, what type of glue would work in this situation? This question also goes for the strain relief on the extruder. Thank you.

Matty vee - Reply

Hi Matty, the whole bundle will be “clamped” in step 10, so there is not need for glue. Just make sure it is tightened properly according to the instructions.

Jakub Dolezal -

OK, I see now. I'm patiently awaiting my mk3 and I'm just going over the assembly instructions before it comes. Thank you.

Matty vee - Reply

My box was missing the shorter nylon fibre, so I ended up using a piece of “strimmer” nylon which was a bit thinner (2.2 mm). It’s more bendy than the correct fibre. If anyone thinks this is a problem, please let me know!!

Bill Evans - Reply

Hi Bill, does your kit included spiral wrap or textile (braided) sleeve for the heatbed cables? Because for the textile sleeve there should be no filament inside. Using softer filament for the spiral wrap than included by us should be ok.

Jakub Dolezal -

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 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.
  • 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.

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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!

M3-8 might be a better fit - I’ve got almost 2mm of screw sticking above the nut on the top side.

Robert Wallace - Reply

Hi Robert, for the MK3 we are unifying the length of the screws as much as possible to make the assembly easier for you. That is why mostly M3x10 is used.

Jakub Dolezal -

I ended up using an M3x8 dome-head screw from my stores - dome-head to provide less for the thermistor cable to (potentially) rub against.

Robert Wallace - Reply

How come there are 3 black “wires” all of a sudden? The previous step just shows one.

Peter Larsen - Reply

One is the NYLON Filament, (from step 5) to help with the cable management and the other two are from the heatbed.

Joseph Rigdon - Reply

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. 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.
  • 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.

  • 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.

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Use the spiral wrap and wrap the cables from the heatbed including the NYLON. Start by one or two wraps 1 cm behind the heatbed cover. When the first wrap is ready, slide it inside the heatbed cover. Ensure it is at least 5-6 mm. Continue with wrapping the spiral wrap.
  • Use the spiral wrap and wrap the cables from the heatbed including the NYLON. Start by one or two wraps 1 cm behind the heatbed cover.

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

  • Continue with wrapping the spiral wrap.

  • DO NOT cut the filament, you'll need the full length.

Trying to get the Nylon filament, two fat heater wires, two small thermistor wires and then 1 cm of spiral wrap into the cover was simply impossible. I had to use a Dremel tool to carefully widen the wiring channels inside the cover and the exit opening at the back. Even with those modifications only about 6 mm of spiral wrap would fit inside. The tightened cover did look like the last picture in Step 10 and the thermistor wires were not pinched {as shown in the first picture). But it required a special tool (Dremel) and a lot more work than simply applying the spiral wrap and tightening two screws.

Bill Waring - Reply

Hi Bill, pushing the spiral wrap in 6 mm is enough, I will adjust the description.

Jakub Dolezal -

It was a lot of work but with some extra twisting of the spiral wrap, I managed to get the entire bundle in without having to widen the hole in the cover and screw everything down. Not easy though, I was sure the printed part was going to break with every turn of each screw, but in the end it worked.

Bas - Reply

Place second part of the cover on the top of the  spiral wrap. 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!!! (see the first picture top left corner) 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 spiral wrap.

  • 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!!! (see the first picture top left corner)

  • 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.

  • Ready? Jump to Step 19

The cover didn’t completely close down for me on the side with the thermistor cutout, so I didn’t need to maneuver the thermistor cables into the cutout. Fortunately, because the cutout is positioned right behind the head of the screw in the heatbed and it would have been a pain to get the cables behind the screw head and through the cutout. For a future version I’d suggest moving the cutout slightly to the side so that it’s no longer blocked by the screw head.

Bas - Reply

The cover hole is too small for the spiral wrap. The cover couldn’t close completely without bending.

Halle Shelton - Reply

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

  • Heatbed MK52 (1x)

  • Spiral wrap (1x)

  • There are two spiral wraps remaining, use the bigger (thicker) one. You have to fit inside more cables now.

  • M3n nut (1x)

  • M3x10 screw (1x)

  • Heatbed-cable-cover (1x)

  • NYLON filament 30cm (1x)

“Bigger”is subjective. It could mean longer, it could mean larger diameter, it could mean thicker….

RWReese - Reply

Thanks, instructions updated.

Jakub Dolezal -

For this step please use the shorter one and DON'T TRIM it! Using the pliers cut one end of the filament to create a tip. Check the tip is similar to the third picture.
  • For this step please use the shorter one and DON'T TRIM it!

  • Using the pliers cut one end of the filament to create a tip.

  • Check the tip is similar to the third picture.

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Push the filament in the hole in the heatbed-cable-cover.
  • Push the filament in the hole in the heatbed-cable-cover.

  • BE EXTREMELY CAREFUL as the pliers tends to slide and you can easily harm yourself or break the printed part!!!

  • To make your assembly easier, check the filament is curved up (as in the picture).

  • If you have issues, try to adjust the tip on the NYLON filament.

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Insert M3n nut in the printed part.
  • Insert M3n nut in the printed part.

  • In case you can't press the M3n nut in, don't use excessive force. Take 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.

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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!

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

Add Comment

Do not stretch the black 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. Guide the black thermistor cable next to the heatbed heater cable and wrap it few times around (see the photo). 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 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.

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

I separated the wires to wrap the cable around the + wire.

note that the upper black one is not the wire, it’s the nylon. by looking on the side of the twin stranded wire you can get the impression it is the single red wire…

Think that won’t hurt.

Heiko Schultz - Reply

Be careful not to leave too much slack in the thermistor cable. After a while mine ended up getting caught on the Y-axis zip tie. I think that was the cause of some layer shift/crash detection issues I was having.

Chris Boom - Reply

Use the spiral wrap and wrap the cables from the heatbed including the NYLON. Start by one or two wraps 1 cm behind the heatbed cover. When the first wrap is ready, slide it inside the heatbed cover. Continue with wrapping the spiral wrap.
  • Use the spiral wrap and wrap the cables from the heatbed including the NYLON. Start by one or two wraps 1 cm behind the heatbed cover.

  • When the first wrap is ready, slide it inside the heatbed cover.

  • Continue with wrapping the spiral wrap.

  • DO NOT cut the filament, you'll need the full length.

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Place a zip tie around the heatbed cover to tighten the spiral wrap with cables. There is a channel around the cover designed for the zip tie. Tighten the zip tie, but do not overtighten it! You might pinch (break) the heatbed wires. It should be snug around the stem of the cover, enough to hold the wrap in place.
  • Place a zip tie around the heatbed cover to tighten the spiral wrap with cables. There is a channel around the cover designed for the zip tie.

  • Tighten the zip tie, but do not overtighten it! You might pinch (break) the heatbed wires. It should be snug around the stem of the cover, enough to hold the wrap in place.

  • Cut the remaining part of the zip tie.

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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)

my screws were of very poor quality. One head was not round but egg shaped. Another screw would not take the Allen wrench, Its “hole” was obstructed. Gladly there were two spares! But I wished there were three in spares. Or better quality screws in the first place!

Christoph Stahl - Reply

Push the Y-carriage to the front and place the Heatbed behind. Locate a hole 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 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.

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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.

…and push or cut through any Kapton tape that may be covering the hole - :)

Robert Wallace - Reply

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.

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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

  • Last four screws

A couple of the screws had heads too big to seat below the surface of the heatbed. Luckily there were spares in the spare parts bag that had the properly sized head.

Scott - Reply

For me only 3 from 13 (9 standard + 4 spare) are ok :(

Michal - Reply

Hi Michal, if you are unable to align the screws with heatbed surface, please contact our support at info@prusa3d.com and include photos. Thanks

Jakub Dolezal -

Similar problem but only one of the original 9 was too big, fortunately the spares bag had one that fitted

Chris Tipney - Reply

A couple of my screw head sockets were too loose on the hex wrench. Great to have spares!

One hole in the middle rear had to be chased with a tap.

J Allen - Reply

Same problem here for the screw head sockets. For that reason it is not possible to screw in the screw like it should. Also found good replacements in the spare bag.

Dominiek Leliaert -

Same problem here. Screw head socket not deep enough or to loose to fit the Allen Key. Found spares in the spare bag.

Dominiek Leliaert -

My bag only had 8 (plus 4 spares). Thought is fell off the table or disappeared into a black hole

Josh Miller - Reply

Hi Josh, the amount of screws is checked, are you sure they weren't included in your package?

Jakub Dolezal -

I also had only 8 screws and resorted for one to my spares package.

Stephan Kyutchukov - Reply

I was not able to tighten 2 screws, 1 did not fit quite right. Used spares.

Juhani Lauteala - Reply

I agree, the screws are of very poor quality.

Please upgrade these screws in future deliveries.

Dennis Sladek - Reply

The top left screw is stripped.. all the other screws went in mostly fine. I feel like you need either higher quality screws, a better hex driver, or bigger screws that are more resistant to the tolerances of the bottom of the carriage…

Mr Cookie - Reply

I had to be careful with the thermistor cable and gently push it a bit out of the way when inserting the spacer to the back left corner.

Kari Söderholm - Reply

FWIW my screws were all fine.

Andreas Sjolund - Reply

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

  • 24V Power supply with cover (1x)

  • M4x10r screw with dome head (2x)

  • M3x10 screw (2x)

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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.

Instructions for cable management especially for the power supply would be appreciated. Right now I have snarls of wires that I keep setting the printer down on each time I turn it

Chris - Reply

Hi Chris, cable management will come shortly in the next chapter.

Jakub Dolezal -

It would be helpful to note that the cables coming from the power supply should be above the frame (reference the first photo in the next step).

Andreas Sjolund - Reply

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.

Hi,

While assembling the power supply both bolts that were supposed to go into the PSU HOLDERS I was having hard time to screw them in. One stripped and broke.

Please advise.

Valentin Bulbuc - Reply

Hi Valentin in case of a broken part, please contact our support immediately (info@prusa3d.com)

Jakub Dolezal -

Getting closer! Just one more chapter and the assembly is done!
  • Getting closer! Just one more chapter and the assembly is done!

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

  • Ready for next chapter? Lets move to 8. Electronics assembly

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Finish Line

165 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

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114 Guides authored

8 Comments

30 minutes. Wondering how tight the bed should really be?

Scott - Reply

Hi Scott, tighten the heatbed with reasonable force. Thanks to the 9 mounting points it holds very well.

Jakub Dolezal -

I have two extra M3x18 left over. They are labeled on the bag but I don’t see them used in any steps.

Graham McIntyre - Reply

+1 me too - in the spare bag they go.

David Beach -

Two extra M3x18 screws here as well.

Douglas Shelfoon - Reply

30 mins. same m3x18 left

Cedric Young - Reply

45 minutes. :D

Zaz - Reply

took my time 45-60mins. same 3x18 left over

allan arthur - Reply

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