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Did you know...#ExtruderSPECIFICS

Updated: Feb 6, 2021

The real bottleneck of your 3D printer’s performance is the combination of heater, nozzle and extruder. While we briefly discovered the nozzle quality and features before, we recently dived into the extruder features, especially focusing on the point raised in this comprehensive MIT paper.

However, as papers usually cover only a specific set of features this paper was no different.

Therefore we will now look into the specifics of extruders!

There are a number of key factors relevant for extruders which are the following

  1. Force

  2. Speed

  3. Acceleration

  4. Precision

  5. Weight

  6. Mechanical reliability

(As of now, the above factors are not linked, however, as this blog series continues, we will update them with links showing you more specifics)

Each factor in its own has to be accounted for, in order to deliver the optimal result in 3D printing. But if you intend to push your results all of them have to be taken into consideration.

Now those factors all come into the equation differently:

Force, primarily works for extrusion speed but also for reliability. The quicker you print the more force you require, even if you use a nozzle with a longer chamber. A filament that is close to clogging (ie due to filament diameter variations) can maybe be pushed through by a stronger extruder, while leading to a failed print in a weaker extruder.

Speed of the extruder is usually only required for the maximum retract speed and improves the quality of your print. When extruding we have never achieved the max. travel speed of a good extruder.

Acceleration is also impacting print quality through retract but can also slow your printer down a lot. Especially geared extruders may have a problem with fast acceleration as gears usually have a max acceleration before they jam.

Precision usually can become an issue with geared extruders, as depositioning of very small amounts of molten filament becomes impossible to control with systematic backlash.

Weight plays a major role with direct extruders, as the weight of the extruder will also have to be accelerated by the gantry. The heavier the head, the slower the gantry has to move in order to avoid ringing. The problem multiplies if you intend to use multiple extruders in one setup.

Mechanical reliability is just what you would expect, only that it refers to the specific design features of the extruder. The more reliable an extruder works the more its likely to do what you want it to do. However, we encountered unreliable extruders primarily in cheap knockoffs or bad designs. They are usually down to a not too well thought out design or low standards in manufacturing.

Conclusion: Always take into account all factors when buying an extruder. You may want to resist the temptation to buy a “cheap” extruder as you are likely to spend many hours calibrating it and if its not well made and the performance is spotty this time is simply lost, let alone the filament you waste along the way.

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