How to clear a blockage - Me3D Support

How to clear a blockage


When to check for a blockage

You should check for a blockage in your extruder if you hear any loud clunking/ticking noises coupled with inconsistent or no extrusion during a print. Other indicators of a possible blockage include your filament being ground down by the pulley inside the extruder, not being able to manually extrude filament or having difficulty loading and unloading filament.
 

Why did this happen?

A blockage can be caused by a number of things:
- Something is trapped inside the nozzle.
- Hot plastic sitting inside the extruder for too long. 
- The fan is not cooling the extruder sufficiently and filament is being softened outside of the desired melt zone. 
- Nozzle is blocked externally by old caked-on burnt filament.
- A small piece of filament has snapped off inside.
- Something went wrong whilst using flexible filament.

Some simple printer maintenance can go a long way to reduce the chance of a blocked nozzle. This includes:
- Cleaning off excess filament from the outside of the nozzle. See Cleaning the extruder nozzle.
- Unloading filament from the printer if it not going to be used for extended periods of time.
- Don't leave the extruder hot for extended periods of time (whilst not extruding material).



How to clear a blocked nozzle


Take caution when running through these steps if your printer is part of a BuildBee enterprise subscription. Others may still be able to access the printer while you are performing maintenance.

Step 1 - Manually extrude some material using BuildBee

Blockages are often resolves by removing and reloading the filament.
- Power up your 3D printer and connect to BuildBee.
- On the 'CONTROL' page in the maintenance console of the affected printer, preheat the extruder to 220°C. 
- Use the 'RETRACT' button to take the filament out of the extruder.
We recommend using Me3D Max PLA when running through the steps to clear a blocked nozzle.
- Clip a new piece of filament to a sharp point.
- Use the 'EXTRUDE' button to slowly feed the filament into the extruder and extrude a small amount of plastic.
- If the blockage was small enough, extruding some new filament through may clear the nozzle. If the blockage remains, you may use your hands to gently push the filament into the extruder as you click the 'EXTRUDE' button. Sometimes, the extra bit of force is enough to clear the blockage.
- If you're still not getting normal extrusion, follow the next step to clean the nozzle out using a needle.

Step 2 - Unblock using a needle

- On the 'CONTROL' page in the maintenance console of the affected printer, preheat the extruder to 220°C and raise the extruder arm using the 'UP' button. 
- Use the 'RETRACT' button to take the filament out of the extruder.
- Wipe the cleaning needle from your printers maintenance kit and carefully insert it into the nozzle from the bottom side. Make sure you don't push the needle against the sides as this might damage the inside of the nozzle.
Do not attempt to use anything thicker than the nozzle diameter (0.4mm).
Make sure you've raised the extruder enough so that you can safely access the nozzle without burning your hands.
- Pull the needle out and check for any residue coming out of the nozzle. Clean any residue off the needle while its still hot (a piece of scouring pad is good for this).
- Try manually extruding a new piece of material similar to step 1. If you're still not getting normal extrusion, follow the next step to perform a hot and cold pull.

Step 3 - Hot pull

- On the 'CONTROL' page in the maintenance console of the affected printer, return your printer to the home position by selecting the 'HOME' button, then preheat the extruder to 220°C.
- Use the 'RETRACT' button to take the filament out of the extruder.
We recommend using Me3D Max PLA when running through the steps to clear a blocked nozzle.
- Clip a new piece of filament to a sharp point.
- Use the 'EXTRUDE' button to slowly feed the filament into the extruder until a small amount of plastic comes out of the nozzle or until the filament won't go any further. 
- Once the filament has reached the nozzle, let it sit there at this temperature for a few minutes without extruding any filament.
- Use the 'RETRACT' button to pull the filament back out. Cut the tip to a sharp point again.
- Repeat this process until the tip of the filament looks clean and you can push filament out normally.

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