How to prevent and clear 3D printer blockage

Understand the cause of the blockage

Regardless of your printer, the best way to prevent clogging of 3D printing consumables is to pay attention to them in advance. You can understand the structure of the 3D printer (including the extruder) by understanding the correct storage of consumables and understanding the tolerances of the printer.jams and clogs are usually universal issues.

Filament tension

In order to minimize the external tension of the extruder, please ensure that your 3D printing consumables are correctly loaded into the printer. Normally, the tension from the filament to the extruder will cause the printer to fail to extrude. Each printer has a different corresponding method of loading consumables, please use the most suitable method to use consumables.


Each consumable needs a different printing temperature, and the appropriate temperature is needed. If your hot end temperature is too low, it may cause two situations, called Case 1 and Case 2.

Situation 1-The hot end of your printer is too cold, and the consumables cannot be extruded at a proper speed or cannot be extruded. So much so that the hobbing bolts have worn away the consumables, leaving nothing to pull. This blockage can be removed more easily by increasing the temperature of the extruder. Before raising the temperature of the hot end, remove the consumable debris from the extruder motor and hobbing gear.

Situation 2-The hot end of your printer is too cold. The temperature is just enough to heat up the consumables and fill the extruder, but the temperature cannot allow the consumables to be extruded quickly in the extruder, so that the cooled plastic quickly fills the hot end. Consumables stay in the hot end for too long and will harden. This kind of blockage is the most difficult to remove.

If the hot end of your printer is too hot, as long as it stays flowing, it will usually not be clogged, but it will cause the consumables to squeeze abnormally, appearing as resistance or leaving air bubbles.

If you leave the 3D printing consumables in the nozzle with a higher temperature for a long time without extruding, it will cause the blockage of Case 2, which is called thermal creep.

What is thermal creep

Thermal creep means that the 3D printing consumable plastic heats beyond an area "melting zone", and the melted plastic "creeps" to the thermal fracture area. Especially PLA consumables, due to their low melting temperature and high heat capacity, are prone to thermal creep. Thermal creep can be remedied by temporarily raising the temperature, extruding and then cooling down, or manually pushing the consumables. In all cases, please ensure that there is an active cooling fan in the Peek or metal radiator when the hot end is at a high temperature.

Nozzle height

The key to successful extrusion of a 3D printer is the correct nozzle height. If the nozzle is too close to the printing plane at the start of printing, it will cause reverse extrusion and block the nozzle. If your nozzle is too far away, your filament will print in the air, which means your filament will not stick to the printing surface. As shown below.


Bed calibration

You want the print bed to be as level as possible, so if you want to prevent paper jams, you must calibrate it. As we have already mentioned, if your nozzle is too low, you will cause retrograde extrusion, which is likely to cause clogging. If it is too high, you may not cause a paper jam, but you will get a lot of plastic on your hands later.

Clear blockage

There are several techniques for clearing blockages. You should first heat the hot end to a temperature slightly higher than usual. This is applicable to any kind of consumables. The temperature can be set 5-10°C higher. After heating, pick up your filament and push it over the hot end by hand. If the filament you are printing is very malleable, you can use a screwdriver or similar tool to push it, but don't push it too far to avoid damaging the hot end.

If this method suitable for most blockages cannot solve the blockage, the following two methods can also be applied.

If your consumables have been worn away, you can check the printer's extruder, you will find that the plastic is covered with the teeth on the hobbing bolts. If you do not want to accidentally invalidate the warranty, please consult the 3D printer manufacturer before performing important maintenance, if you do not want the printer warranty to expire. Use the arrow tool to gently scrape the plastic from the tooth clock. Your bolt has the ability to pull the filament. Tightening the drive block a few turns may also help. Likewise, you may need to check the condition of the extruder before trying.

If none of these are useful, there is another way, depending on the nozzle size, you can use steel high E strings (the kind on standard acoustic guitars) or acupuncture needles (available online). Insert the string/needle into the tip of the nozzle, heat the extruder as needed, and slide it back and forth inside. This allows you to remove small pieces of hardened plastic and smoothly squeeze out the filament. Note that although effective, it is a bit dangerous. Don’t try unless you are sure you don’t need outside help.

Most machines can completely disassemble the heating device, but as mentioned above, the warranty may be invalidated. If you can loosen the nozzle, you can use a hot air gun or blowtorch to melt the remaining filament (do not do this without proper safety measures or under supervision). Once the extrusion path is unobstructed, the nozzle can be reconnected.

When I have tried all the methods to fix the clogged nozzle, but the 3D printer still cannot extrude normally, how to solve it?

Printer manufacturers usually provide support for a period of time, and they are most familiar with printers. If this does not work, you need to buy a new hot end. Don't worry about the cost, and it's fairly easy to replace-sometimes it's best to upgrade the extruder or hot end immediately to avoid clogging.

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