3d printer Extruders

3d-printer Extruders

In my experience as a maker, one of the main concerns I have as a 3D printer is getting the ideal resolution for every piece I print.

Extruders are an important part of this topic. They provide the necessary settings for each print, which is why we must use the right extruder for our purpose.

Imagine you are an artist, and you can only use a single pencil for all your drawings. The results wouldn’t be as good as they will be if you used different types of pencils to give a finishing touch.

The same concept applies to 3D printers. You can print in different kind of materials for different finishes.

Knowing about the essential components of extruders allows us to know how to operate our 3D printers. It will also make it easier to maintain the 3D printer.

In order to do this I will list the most common components in an extruder, and describe the main extrusion technologies.

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Main Components on FDM 3D-Printer Extruders:

Stepper Motor: This motor is used for drawing the filament from the spool through the nozzle to be deposited over the build plate. It is controlled by electronics attached to the 3D printer and rotates in small steps (fractions of a rotation) to release the exact amount of material needed.

Gear Drive: This part goes over the drive shaft of the stepper motor. It works with a belt to move the tool head.

Retraction / hobble gear: In some cases it can be used as a diameter gear on the motor shaft in order to increase the force applied to the filament used. The gear touches the filament directly through the engine and it transmits the rotation, along with filament retraction

Bearings: A simple ball bearing presses the filament through the drive gear, holding it in alignment with the filament guide.

Filament guide: is a simple tube of plastic straight from the engine to the hot-end. It has the right diameter to pass the solid filament to the hot-end. Most common filaments are 1.75 mm or 2.85 mm.

Hot-end: This piece will melt the filament so it can flow through the extruder nozzle.

Temperature Sensor: This element is responsible for measuring the temperature levels and pass reading data to the control system of the 3D printer.

Nozzle: This is a cone which the hot material is extruded from. The diameter of this orifice hole is most commonly 0.4 mm, along with 0.3 mm and 0.5 mm.

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Extruder Technology

Direct Extrusion

This is the simplest extrusion system that exist. It is commonly used on RepRap printers like the Prusa i3.

The filament is drawn directly from the engine into the nozzle, passing through the hot-end to be deposited on the bed. This is the simplest extruder design on the market.

Advantages

• Compact
• Easy maintenance
• Easy to clean out jams

Disadvantages:

• Heavy,which can affect the movement of the x and y axis.

Bowden Extrusion

Bowden extrusion is another type of extruder.It is similar to direct extruders in that the filament is drawn to the nozzle.  However the thrust motor is separated from the hot-end (see Diagram below). The filament is brought to the X axis carriage via a flexible pipe.

Advantages:

• Lightweight,  because the engine is separated from the hot end.

Disadvantages:

• Complexity, it can be more difficult to assemble and maintain in operation .