The extrusion process

In the extrusion process, the material is fed through a pair of rotating cylinders: one (the “speeder”) with teeth that grab and pull the plastic onto it; another (“guide rollers”), which move in tandem with the grooves on the speeder to push it. As the material exits the nozzle, it is pushed onto the print bed, where it settles in the form of fine lines, until sufficient layers are formed to create solid objects again.

The gear is responsible for transforming the filament into layers and is powered by a spool. The guide wire is the tube that allows the filament to reach the tip of the head. The filament is pushed down through the extruder, until it comes through the guide to a nozzle.

The heated head is a metal block with a heating element inside. When this heats up “the nozzle has reached temperature”. Once it reaches temperature, anything that touches it will begin to melt; this will allow us with our extruder to push the filament inside allowing it to melt. The heated print head pushes the plastic filament out onto the platform. The molten material cools as it exits the nozzle, creating overlapping layers to form solid objects again.

Types of extruder

There are two types of extruders we use in 3D printing: Bowden and Direct. Bowden extruders are the most common in FDM printers. They use a flexible tube to push the filament into the hotend and keep it there. A motor is used to spin the filament and pass it through the tube, which can be made of different materials, including PTFE (Teflon), nylon or PETG (polyethylene terephthalate glycol). The advantage of Bowden extruders is that they can be used with heavier materials.

Direct extruders work by pushing filament through a motorized hotend using only the force of the motor itself. This means they can use lighter materials, such as PLA and ABS, which are less likely to break under pressure. The disadvantage of direct extruders is that they cannot handle heavier materials. Bowden extruders are more expensive than direct extruders, but the benefit is that they provide a smoother and more consistent flow for printing with different types of filaments.

Common problems

Knowing the parts of the printer is essential to be able to use it and solve any problems. the most common problems for an extruder are:

-The filament is not feeding properly through the extruder. The filament becomes tangled, creating a knot that prevents the printer from extruding properly. Filament jams in the feed mechanism and does not feed properly. The filament tangles and stops feeding at the hot end, causing the extrusion to stop.

-The nozzle is clogged with plastic or other. The filament gets too hot, melts and sticks inside the extruder. This can be caused by too high a printer temperature setting or insufficient number of cooling fans. Filament is stuck inside the printer and needs to be removed.

-The motor overheats and fails to feed the filament. The engine is broken or defective. The wiring is badly connected or broken.

-The extruder gears are stripped or broken. Filament is not feeding properly through the extruder. The most common cause of this problem is a lack of sufficient pressure on the filament, which can be caused by: A worn or broken gear on the motor drive pulley. Excessive loosening of the wiring or cables. The stepper motor itself fails and stops working properly.

-The filament does not pass properly through the extruder. If the filament does not feed properly, a few attempts can be made. First, check that the filament is not tangled or entangled anywhere on the extruder. You may need to remove any plastic buildup around the nozzle or elsewhere in the printer. Next, check that the extruder gears rotate freely by hand and are not damaged or broken. If they are damaged, replace them with new ones.

Conclusion

If you want to know more about the extruder for 3d printing and how it works, take a look at the other articles! If you are interested in learning about other parts of a printer and how they work, check out the other articles!