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Nozzle Cleaning / Unclogging

The KODAK Portrait uses all original E3D components including

  • Titan Extruders
  • E3D V6 All-Metal Hotend (right side)
  • E3D V6 Lite Hotend (left side)
  • Capricorn PTFE Bowden tubes.

For further information about these components and guided access https://e3d-online.com/

What Causes 3D Printer Nozzle Clogs

To understand a clog, it’s probably best to know a few things that can cause the issue in the first place.

Although there are different types of obstruction that may be called a clog these issues can be classified into two groups:

Problems related to the malfunction in a component of the entire system responsible for moving and melting the plastic.

These are generally mechanical issues or problems associated with the material getting stuck temporarily or overheated in certain areas of the system ( Extruder – Bowden tube – Hotend ) were the heat is not supposed to reach.

This cases of obstruction or binding occur due to the filament not having a clear path from the point where it goes into the printer to the point where it goes out.

Filament stuck to the walls of the heatsink on the left hotend.

This also includes problems related to heat reaching upper parts in the hotend and this causing the filament to dilate at points where it should be cold.

Another thing to check is the filament tension, make sure that your 3D filament is loading into the printer properly, with minimal tension outside of the extruder. Be sure that the spool of filament is mounted and is able to spin freely – often tension from the filament leading to the extruder can cause a printer to stop extruding.

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Filament tangled inside the spool case.

Problems caused by the accumulation of rests of material or degradation of it inside the heated areas of the system.

These problems are more related to the chemical aspects of the material were its internal composition is affected beyond return, this happens if the material is exceeded in temperature or if it is maintained for too long inside of a heated section of the hotend without being extruded, as the material is “cooked”.
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Burnt material.

How To Check if Your 3D Printer Nozzle is Clogged

Preheat the selected hotend and position at the back of the printer, while pulling the titan extruder lever up push filament through by hand. If the filament string curls, is hard to push through or doesn’t come through at all, the nozzle is clogged. It shouldn’t take much force to extrude it manually, a few cm’s of material should be able to come out of the nozzle easily before pressure builds up.

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In the case of specific materials such as PVA or Flex, this behavior may vary a bit as these materials require a slower flow rate. In this case, the test can be performed using the manual controls to push the filament in a slower fashion.

Once the hotend is heated up the user should be able to push material through the hotends using the manual controls at least 3 times, if material flows out of the nozzle while doing this the hotend is not clogged. Check that no “clicking” sound is heard while the extruder is extruding.

This doesn’t ensure there is no partial clog so in this case, the user may want to send a small print to verify this.

Also, it needs to be checked if inconsistencies are noted while printing such as poor material laydown or difference in the flow of the plastic while printing a model.

If the filament gets ground it may also be a sign that it’s not being able to flow freely through the nozzle.

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See Extrusion issues

Working principles – Hotends 

Materials behave in different ways when they are melted, for this reason, our printer features 2 different hotends, the V6, and the V6 lite.

It is important to understand the difference between both hotends and how they work, as most issues related to clogging can be easily solved if the hotends are assembled and used in the proper way.

Although hotends in the Portrait may look the same, the heat break in both of them is different

The heat break is the sector that separates hot and cold areas in the hotend.

If the heat goes above this point the functioning of the hotend gets affected.

Red circles mark the heat break for each hotend.

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Left hotend uses PTFE (Teflon tube) in the heat break and Right hotend features an All metal heat break.

For assembly instructions on the hotends please access: How to assemble Hotends

E3D V6 LITE ( PTFE hotend – left side)

In the E3D lite6 (v6 lite) the heat break is part of the heatsink itself and the PTFE Bowden tube travels through it up to the bottom were it establishes contact with the nozzle.

The advantage achieved by getting the PTFE far in the heat break is that it allows the material to flow easily even if the material is melted as it slides easily due to the properties of the Teflon.

PTFE hotends are meant to print the stickiest materials such as PLA’s, flex’s, and specific materials like PVA as long as they don’t require more than 235 c of temperature to allow the print process as the PTFE will start to degrade and wear out.

The Capricorn PTFE allows this material to slice through the hotend easily while also allowing for retractions of it diminishing the chance of clogging vs an all-metal hotend.

It is extremely important that the  PTFE is cut at a 90-degree angle and inserted up to the bottom in order for it to contact perfectly with the nozzle’s backend. This seals the path for the filament to flow through.

If the hotend is not assembled correctly and the PTFE is not inserted to the bottom it may lead to filament melting at a point between the nozzle and the PTFE thus creating a clog as the filament gets chambered and melted in direct contact with the heat block.

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Example of an incorrectly assembled lite hotend. The blue Bowden tube is not perceived at the end of the heatsink.
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Example of a correctly assembled E3D V6 lite. The PTFE is seen at the end of the heatsink.

For assembly instructions on the hotends please access: How to assemble Hotends

E3D V6 ( all metal hotend – right side)

In the E3D V6 (V6 all metal) hotend the heat break is a separate metal part which joins the heatsink and the heat block together. Like the V6 lite, this heat break needs to contact tightly with the nozzle to seal the path for the filament to flow and avoid clogging or material leaking out of the hotend.

On the other end of the heatsink, we also find PTFE tubing and which must also be cut at a 90-degree angle and contact tightly with the heat break.

The V6 all metal is meant to print a wide range of materials using temperatures up to 295c degrees. This hotend excels at printing more technical materials such as ABS, HIPS, NYLON6, NYLON12, PETG.

E3D All-metal heat break

For assembly instructions on the hotends please access: How to assemble Hotends

Causes of a clog

1) Heat Creep: if the hot end isn’t cooled properly, filament starts getting viscous too high up in the hot end and we run into an issue called heat creep. This is when filament liquefies too high up and the extruder has to exert much more force to push it through the nozzle until it eventually becomes unable to and jams up.

We refer to heat creep when parts of the hotend above the heater block get too hot. Under normal circumstances, the filament starts melting just above the nozzle. However, when the heat break gets too hot, the heat expands upwards irregularly throughout your hotend, the filament starts to soften higher inside the hotend and causes a clog. The extruder motor grinds into the filament, it can even make a “clicking” or “ticking” sound as it tries to push the filament down the extruder.

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Pay attention to grinding noises in the extruder or clicking when the filament is jammed and if that’s the case, stop the print and remove the filament, cut the tip and input it back again. Make sure the cooling fan for your hot end is running properly and ensure that the heat sink and heater block are securely attached.

If the hotend prints normally for some minutes after the print is launched but then the print starts failing then the printer may be affected by heat creep issues. Always ensure the printer is being operated within the normal operating temperatures and try removing the printhead’s lid.

2) Low printing temperature: If the hotend’s temperature is too low, the filament will not be able to be fed through at a consistent rate and this will cause the extruder to grind away at the filament, making it even more difficult to extrude.

Check the temperature specifications for the filaments and ensure you are not trying to print at speeds outside the recommended parameters.  If you’re having issues with the listed specifications, try iterating upwards by 5 degrees but make sure not to go above the max temp of your hot end nor the filament. When switching filaments, make sure all of the previous material is removed before changing temperatures.

3) High printing temperature: If the hotends temperature is too high for the material chosen it will start accumulating burnt material in it as it prints, giving no sign of a problem at first but getting completely clogged after some time of usage.

Inconsistencies in extrusion and things such as dripping too much at retractions or the appearance of bubbles while printing may be a sign of higher temperature than necessary.

Check the temperature specifications for the filaments  If you’re having issues with the listed specifications, try iterating downwards by 5 degrees while keeping an eye on the flow rate and layer adhesion. When switching filaments, make sure all of the previous material is removed before changing temperatures.

4) Nozzle distance to the bed: If the nozzle is too close to the bed, there will be no room for the filament to be extruded out the nozzle and this will cause a jam.

The bed needs to be leveled properly. Check out Calibration

5) Particles of different materials / burnt material /dust: If the hotend is not purged correctly in between material usage it may lead obstructions in the hotend as the difference in melting temperature may cause a higher temperature material not to liquefy properly if trying to print another one with lower temperatures afterward.

In the opposite case while switching from a low-temperature material to a higher one if the hotend is not purged correctly the previous material may burn while increasing the temperatures to print the material which requires a higher temperature.

If dust or particles get into the hotend they may burn there increasing the chance for clogs.

Also if the printer is used intensively without maintenance it may lead to the accumulation of different residues depending on the material used. In the case of PVA and Flex materials, this risk increases slightly as they tend to accumulate more residues while printing.

Ensure the nozzle is correctly purged when switching materials and avoid the hotend to stay at printing temperatures for long periods without extruding material as this greatly increases the risk of material degrading and burning inside the heated part.

Different ways to unclog a nozzle

Required equipment and materials

  • Nylon filament
  • Cleaning needle
  • Crescent wrench
  • Socket wrench
  • Pliers
  • A heat gun or blow torch / direct flame.

Remove the printhead’s lid

First, remove the silicone block and preheat the nozzle to 200 c to clean the rests of the plastic on it.

The first thing that you should try in the event of a filament jam is heating your hotend up to a slightly higher temperature than you normally would, for whatever material you were printing with. Typically 5-10°C higher is a good place to start. After it heats up, takes your filament and try pushing it through the hotend by hand.

Method One: Cleaning needle

One problem that can occur is that cold material or rests of burnt material stay glued to the inner surfaces of the nozzle (especially when switching different materials as their melting points may be different).

This prevents material from extruding properly or at all. The first thing you should do is heat the extruder and the nozzle to soften the clogged material, then try to clear the partial or total blockage with the needle provided in the toolkit ( the needle is attached to the paper ruler).

  • Preheat your printer to the print temperature of the last material you were printing with.
  • Gently and carefully insert the cleaning needle up through the nozzle.
  • While inside the nozzle, turn the needle a few times.
  • This isn’t meant to remove the particles,  the idea is to break them and to unstick all debris attached to the insides of the hotend so this rests of material can be pushed out the next time filament is extruded.
  • Try to extrude material using manual controls, the material should come out cleanly.mceclip2.png

Method Two: Filament cold pull

The idea behind a cold pull is that you set your hot end to the glass transition temperature of your filament. This is the temperature at which the filament is between both a solid and a liquid. This allows you to pull out the filament and take any residue along with it. This works best with Nylon, Flex or ABS and lastly PLA.To do a “cold pull”  it is preferable to use Nylon Filament as it can withstand higher temperatures and it is also very resistant to traction forces.

  1. Heat up the nozzle to the temperature of the filament you are going to use to perform the cold pull and push the filament through the nozzle until you don’t see any of the previous filament coming out of the hotend. If the nozzle is completely clogged and no filament is coming out try to ensure the tip of the filament is reaching the heated area of the hotend, so its tip can fuse with the clog.
  2. Let your extruder cool down to room temperature to solidify the filament in the nozzle. Wait until the hotend has cooled down and given it 5 minutes.
  3. Set the hotend to preheat at the selected filament temperature once again and watch the temperature gauge.
  4. At 90°C, lift the titan’s extruder lever and pull on the filament until it yanks out of the nozzle, this must be done in a place with enough space so the user can use some strength if necessary and avoid injuring itself if the filament snaps. The desired result is to get the shape of the inside of your nozzle at the end of the filament. You should be able to see the clog or particles in it.
  5. Repeat this process until no more debris or burnt material is found.
  6. Again, heat up the nozzle and push the filament through until it comes out clean and easy.

If filament comes out too easily and there is no residue on the end, lower the temperature.  If you have trouble pulling it out, raise the temperature until it does.

Repeat this procedure 3 to 4 times until the tip of the filament comes out clean.

A successful cold pull will show that the tip of the filament copies the inside of the nozzle

This will be an indicator that the procedure was carried out at the appropriate temperature, since the material will not melt and, in addition, it will be perceived that there are no obstructions or burnt filaments at the material outlet.

Tip of the filament after a successful cold pull.

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Cutaway of an E3D nozzle, the area marked in red shows the path the filament follows.

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Method Three: Removing the Nozzle

  • Heat up the nozzle to the print temperature of the last material you used.
  • Use a crescent wrench to hold onto the heater block, while you use the socket wrench to twist off the nozzle. Ensure the grip is firm to avoid the tools from slipping and damaging the hotend’s cables or even the metal parts.
  • Be careful not to touch any of the hot parts
  • With the nozzle removed, use heat to melt the filament out. Chemicals can also be used to dissolve and wash out the clog.
    • If your printer clogged after using ABS, simply drop it in a container of acetone and the ABS will dissolve away.
    • There are chemicals you can use for other materials, but they tend to be more caustic or hard to find. In those cases, a heat gun or blowtorch (using the proper safety precautions) can melt out the remaining filament.
  • With a heat gun or blowtorch, wave the heat over the nozzle like blow-drying your hair; direct heat from a blowtorch can actually melt your nozzle.
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