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MK8/MK7 Nozzle Cleaning Script

by jetty, published

MK8/MK7 Nozzle Cleaning Script by jetty Sep 14, 2012


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Request: Because this is a script and not an object, if you use it, please take the time to make it a derivative, click on "I Made One". Thanks!

The brass nozzle on your MK8/MK7 stepstruder gets charred ABS on it over time.

Not only is this ugly, but if the deposit is around the nozzle output area, it can affect your printing too.

Clean up your nozzles with this handy script. The script prints a cube with a nozzle shaped indentation in, and then it slowly buries the hot nozzle inside.

Allow the nozzle to cool, then remove with pliers for a shiny clean nozzle.

Credit goes to Crazy Jaw for the original idea in his post: "Possibly brilliant (or terrible) way to clean an extruder nozzle" on the makerbot forum.

Disclaimer: Using this technique puts some force on your bot's mechanics. I've encountered no issues myself with this technique. If it's so stuck on you're risking damaging your bot, then you can preheat your bot to release the bond. Use at your own risk.


  1. If you have any pieces of kapton loose underneath the heater block, trim these first so they don't get embedded in the plastic.

  2. Print the correct gcode file for your extruder (details below). The gcode files are special and contain code at the end to center the nozzle in the cube and slowly bury it.

  3. Allow nozzle to cool to 70C

  4. Move platform away from nozzle

  5. If the cube didn't detach from the platform in step 4., use pliers to remove from the nozzle

Machine specific notes:

Replicator (5.5 Firmware): Use CleanMK8Left.gcode / CleanMK8Right.gcode for non accelerated, and CleanMK8AccelLeft.gcode / CleanMK8AccelRight.gcode for accelerated. Left refers to the left extruder and Right to the right extruder. Note, if you have a single extruder, then you should download the "Right".

If you want to clean 2 extruders at once, download the "Left" version and then use a dual printing script or "Firmware Ditto Printing (TBA)".

Thingomatic (Jetty Firmware): Use CleanMK7.gcode. Jetty firmware recommended, for other firmware, machines , non stock configurations you'll need to rebuild the .stl for your own use.

Rebuilding .stl:

Print 25% fill and 5 shells. Accelerated printing is fine. Then compare your gcode to the gcode attached to this thing at the ends of the files, you need to remove any homing, clearing the print movement at the end of the print, and before the nozzle cools, center the nozzle over the print, and then slowly bury the print into the object. See how it's done in the attached .gcode.

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There is a guy on Ebay selling some plated nozzles. They might not char as much to begin with. I guess they are coated with some kind of release plating thats used in injection molding. ebay item # 321667110675

Is there a recommended temp at which to remove the cube?

just a idea to make this more universal, make the "hole" smaller and fined on the inside so it has more plastic to stick to without higher infill/shell levels, make part of the model a printed floating island 20mm above the desired "implanted nozzle" position. this way all one needs to do is find the island part of the code and add a predefined code to the gcode that is locally made.

I have a few of the 20mm calibration cubes kicking around. As soon as I tried CrazyJaw's technique and verified it work, I pulled these cubes out of my recycle bin to be used for this exact purpose. And some of the larger failed prints too. Still, this script will be handy! Thanks Jetty.

I've done the same too with the 20mm cubes (been printing a lot of them recently).

The reason for the script is to improve the process a bit. The hole in the cube matches the nozzle shape which provides more contact further up the nozzle, i.e. you get more of it clean than you can with the 20mm cube.

hahaha, that is just one of those awesome mistakes! good job!

Haha, awesome.

I may have been the one to come up with this, after prying off a disaster unattended print (posted a "Possibly brilliant/possibly insane cleaning method" post in the Makerbot google group).

I dig the little cleaning block, though i wish it was a little more plastic efficient. I usually just grab
something from my massive box of failed prints (i view it as a form of recycling ^_^)

Thanks, I've put the credit on.

Regarding the size, it was the most efficient I could get whilst cleaning all of the nozzle and having something that wouldn't be melted through and could be grabbed.

For example, I tried 15% fill and 1 shell, that didn't work well. 100% was the best, but not efficient.

Well what do you know. I've accidentally cleaned my nozzle a few times recently.