Help! I've got a clog in my hotend! What do I do now?

Modified on Sat, 6 Jul at 2:31 PM

Steps for Resolving a Hot-End or nozzle Clog, follow each sequentially until the issue is resolved:

Gradually heat the hot-end to a temperature approximately 10 degrees higher than the recommended print temperature for your current filament.
Remove the PTFE tube from the hot-end, if present.
Attempt to extract any protruding filament.
Utilize the Nozzle Cleaner Tools to dislodge the clog by pushing the shaft downward from above. If unsuccessful, proceed to the next step.
Use the Nozzle Cleaning Needles to dislodge the clog by inserting the needle through the hole in the nozzle. If the clog persists, proceed to the next step.
Execute a cold pull(see below section) and repeat if necessary (refer to the detailed explanation on the opposite side of the page).

If the clog persists despite the above steps, you may need to disassemble the hot-end for thorough cleaning. Follow the steps below for disassembly and cleaning:

Heat the hot-end to a temperature approximately 10 degrees higher than the recommended print temperature for your current filament.
Remove the PTFE tube from the hot-end, if present.
Use the Nozzle Wrench to loosen the nozzle from the hot-end while it is still hot.
Allow the machine to cool down and turn it off.
Choose a clean, flat surface, preferably a high temperature soldering Mat.
Disassemble the hot-end from the machine, noting the order of disassembly and capturing pictures if necessary.
Disassemble all subcomponents from the hot-end until individual parts remain. Ensure the removal of the heater cartridge and thermistor.
Inspect the inner passages of each component (heater block, heat throat, cooling block, and nozzle) for clogs or material. Apply heat to each part with a small torch or heat gun and use tools to dislodge any remaining plastic. A Q-tip can be used to push out material from the inside of the heat throat and cooling block.
Once the parts are clean, reassemble them in the same order, paying attention to ensure a good mating of the nozzle to the heat throat. Additional assembly information can be found in the on our support page or you can contact us for more specific guide or assistance with your printer.

If the above does not resolve the issue, you may need just need new nozzle.

Cold Pull:

All hotends can clog at times, and all-metal hotends can be more prone to clogging with PLA. There are "cleaning filaments" that can help to remove small clogs and debris.

The simplest way to clear a clog in the heat break of any all-metal hotend is to perform a cold pull or atomic pull.

Prusa MK3 (Cold Pull Video)

Prusa Article: https://help.prusa3d.com/article/cold-pull-mk3s-mk2-5s_2075

General Video:

Ender 3:

If that doesn't work, the Mosquito™ and Copperhead™ Hotends have been designed with high temperature materials in mind. Remove the hot block and heat break from the heat sink. Place the hot block and heat break into an oven or kiln (not one used for food consumption) preheated to 100°C above the melting temperature of the plastic. The goal is to incinerate the plastic. Please do not put the heat sink in the oven. It will deform. Also, please do not burn yourself.

If you clog is ABS or related plastic you can soak the component within acetone.

Cold Pull Written Guide

(For the best results, use Cleaning Filament or Nylon Filament, if not filament you print with may also work as long materials is not brittle such as any filled materials like GF/CF or wet PLA)

Heat up the nozzle to ~250c or if you printing with engineering materials to higher ~300c
Load the above mention materials through the hotend/nozzle.
Set the hotend to ~100-115c (for cleaning filament/nylon) for a minute
Set the hotend to cooldown, pull the filament in quick motion, you see something similar in below example of cold pull.
Repeat the process until you can extruder/purge filament from nozzle and if you using cleaning filament it should be pretty clear extrusion.

Example of good/bad cold pulls:

Expected Cold Pull Result (Regular Nozzle):

Credit: https://help.prusa3d.com/article/cold-pull-mk3s-mk2-5s_2075

Dirty:

Clean:

CHT Cold Pull:

Source: https://www.bondtech.se/2021/09/30/the-bondtech-cht-nozzles-are-available-now/

Revo HF:

Credit: https://www.reddit.com/r/3Dprinting/comments/151xtf8/this_incredibly_satisfying_cold_pull_from_a_revo/

Causes of Clogged 3D Printer Extruder Nozzles

Dust build up around filament path, considering running your printer via reverse bowden PTFE from filament to the extruder to reduce dust build up when filament is not used. Store in seal and dry/out of direct sunlight location when filament is not in use.
Low quality filament, lower quality filament may have dust and other contaminants within filament from previous materials extrusion.
Incorrect hotend temperature, this cause materials to crystallise and may cause build up within the nozzle, when changing materials from low to high, ensure the previous higher temperature materials are purge thoroughly before printing.

If the above troubleshooting does not resolve the issue, you may need just need new nozzle, is simplest fix for clog or partial clog nozzle or hotend. If you using PTFE hotend, the other solution you may need replace the PTFE.