3D printer extruder: what does it consist of and how to choose it?
Any 3D printer has specific peculiarities of construction. However, the main component part of any 3D printer is an extruder. In simple words, it is a print head, which creates new objects. It has a simple operation principle: a special nozzle extrudes plastic through it to build a 3D item.
Construction of 3D printer extruder
A standard 3D printer functions using plastic filament. There is a great variety of types, but usually ABS and PLA plastic filaments are applied. Despite the fact that different materials can be used, the extruder is built based on the same principle.
Any 3D printer extruder consists of two blocks:
- Cool end is responsible for filament supply. It consists of a drive gear, pressure generation mechanism, gear wheels. Thanks to the rotating gear wheel, the filament is pushed from the coil all the way to the heater. There the filament becomes viscous under high temperatures. It helps to push the filament through the nozzle and give it the required shape.
- Hot end – a nozzle with a heating element. It is usually made of aluminum or brass, as these materials feature good thermal conductivity. The heater consists of nichrome coil, several resistors, and thermocouple. The hot end heats up and helps to melt the plastic. A thermal insulation between the blocks answers for cooling of the build area.
How to choose an extruder?
For the quality operation of 3D printer, it is important to choose a quality print head. Choosing a 3D printer extruder is a difficult task, but there are several aspects that will help you make a right choice:
- Material type. Modern extruders are either 3D printed or have cast elements. The latter option is more lasting, which is vital when applying severe load. The advantage of 3D printed heads is the low price.
- Filament supply method. Extruder is a very important component part, as it supplies the filament to the heater. The process should go neatly and seamlessly for the filament not to become tangled.
- Type of the feeding roller. It often happens that due to poor cohesion between the material and the feeding roller, the filament starts to slip. It is a common situation with nylon filaments.
- Nozzle parameters. The print head can be equipped with the nozzles of different sizes. The choice of the nozzle diameter depends on the shape we want to obtain in the end.
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