Common problems

Lack of extrusion at the start – Main reasons and solutions

Lack of extrusion

The lack of extrusion when we start printing is one of the first problems we face after buying and mounting the 3D printer.

Fortunately, this problem is as common as it is easy to solve.

As usual we will analyze all possible causes, even the obvious or obvious, we never underestimate the lack of reasoning of our mind in a period of great stress, as it could be the first start of the machine after a night spent assembling it.

If your extruder doesn’t spit plastic out like it should, don’t panic!

First of all, let’s consider that it can happen that the printer stays at a temperature of a few minutes, maybe while we unload the STL or while we prepare the G-Code file with the slicer, in this period of time the heat melts the plastic in the extruder and empties it, so when we start printing we will notice that the nozzle will not deposit anything on the plate, but do not worry, the flow will start only with a small delay, usually a few seconds. To overcome this problem we can set 2 or 3 perimeters of skirt. This option will give the filament time to exit before the printer passes to print the model.

Distraction mistakes

The absence of extrusion can happen, very trivially for a pure forgetfulness, we have not loaded the thread!
While the phases of loading the filament it is advisable, with the nozzle at temperature, to push the wire until it gush out of the wedding.

A variant of the loading failure is the failure to tighten the wheel that pushes the filament against the pulley of the extruder motor.
In the Bowden extruder there is a spring that automatically clamps between the pulley and rotates the filament. Each extruder has a different clamping method. These range from screws to springs and various types of preload. I have spent a few minutes wondering why the extrusion has not been done. Before realizing that the preload screws were not tightened properly.

By starting to talk about the real problems that prevent our beloved plastic from flowing down the wedding we can not help but mention the most common.

Lack of extrusion. Extruder half clogged. – This is the only reason, that it is not a fault, that makes your printer stop extruding while working.

When we are in the presence of a filling we can switch to remedies basically in 2 ways, the fast way and the accurate way.


  • The fast mode involves heating the extruder to a higher temperature, of at least ten degrees, than that used for printing the material that caused the blockage. Then, through the use of a nozzle cleaner, which is basically a needle of the precise size of the hole in our extruder, we will insert it and clean the material that comes out. When it seems unblocked we will have to push the thread manually and see that it flows and comes out with a normal diameter and flow, otherwise we will have to continue with the cleaning.
Lack of extrusion
Nozzle cleaner

You can use this method when you know that the extruder is new, or in any case little used. Otherwise you will have to proceed with thorough cleaning.


Careful cleaning involves disassembly of the nozzle, always remember to dismantle / reassemble the nozzle to the maximum temperature that our extruder can reach.
We can proceed at this point to the heating of the nozzle with a blowtorch, paint stripper gun or if we are in a house without professional tools available through the fire emitted by the stove of the houseUse cousine fires. We recommend the fire of the stove as it is very caloric (if a nice blue).

Do not try to do this work with a simple lighter because it is not caloric enough and it will burn our plastic. The result would be a piece of charcoal instead of our nozzle.  At this point, through the nozzle cleaner of which we have spoken before, we will proceed to get rid of all the plastic present.
To judge our cleaning work we can place the nozzle towards a light source and try to look inside, if you see a nice circle of light you will have released your nozzle well.Nozzle 3d Printer

Now, depending on whether you are using ABS rather than PLA, you can immerse your nozzle in pure acetone (MethylEtilChetone for ABS) or caustic soda (PLA) and leave it to rest overnight. Personally, after having rinsed and dried the piece well, I put a drop of lubricating grease inside it (the grease in question is suitable for high temperatures), the only precaution at this point is that after mounting it pushes out more filament than usual, until it eliminates all residues of grease. (I found that this method prevents re-entry for a long time).

NB: Nozzles are so cheap you can just change them without lose your time to clean them. It’s less then a buck each!

Lack of extrusion: LINKED PROBLEMS

If we had a filling of the extruder and we didn’t notice it immediately, maybe the lack of flow, the part of the filament in contact with the wire pusher wheel, is completely grated and our extruder is full of pulverized residues of filament.
FilamentIn this case, it is advisable to clean the entire apparatus very well and, if necessary, disassemble it completely to provide for a more thorough cleaning (if we disassemble the entire extruder for maintenance, remember to check the state of the PTFE tube inside the screw inserted in the radiator and replace if it is not perfect). Once everything is in the right place, cut off the part of the defective filament and we can get back on track.

Lack of extrusion: Poor filament

Even the filament can “put its own” and increase our difficulties. Many filaments, more often those of inferior quality do not have a constant diameter, (I recommend our reviews for the choice of the filament) which in simple terms means for are more chubby in some specific points. This variation in shape, if very accentuated, can precisely block the flow of the wire inside the extruder. Here, unfortunately, we can not remedy if we do not measure with a digital gauge to sample our filament. In case we find big differences in measurement, extract the wire and put it in the appropriate container of the differentiated.


Lack of extrusion: Another possible cause is the extruder motor that clicks because it lacks power.

Another possible cause of failure to extrude is the lack of power of the motor responsible for the rotation of the wire pusher.
If we are in this case, listening to the motor turn we will hear a ticking at a fairly regular rate. Or, if you can watch it, you will see the loss of the stepping motor. We will notice that the motor shaft will turn back in a snap before trying again to push in the right direction.
This problem is easily solved by following our guide for adjusting the Vref

Lack of extrusion: adjustment of the distance between the plate and the nozzle

Now it is the last of the probable causes of material failure at the beginning of a print job. The incorrect adjustment of the distance between the extruder and the plate.
If our nozzle crawls against the plate, or if it is too close to it, our plastic will not have space to exit. In the best case we will see a very light transparent patina, hardly visible to the eye.
To avoid this problem just lower the plate, leaving the space for a sheet of paper.
You shoul use the screws of the bed. Or directly on the Offset Z inside the firmware or slicer values.


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