The Extruder is one of the critical parts in 3d printer. It’s rather a simple part when explained, but still many people don’t know about the mechanism behind the extruder. Knowing the parts of the extruder will surely come in handy. You can fix or fine-tune your extruder according to your needs if you know the parts behind it’s working.
Its assembly consists of multiple parts which are work Simultaneously to do the job complete in a correct manner so we achieve high-quality print. Manufactures create multiple types of extruders some are standard and some are OPEN Source (Custom made) Extruder. Some Extruders are using Granule or Pellet instead of filament. Some extruders have different materials like chocolate yes they are also custom made, actually, you can use an extruder for any kind of material with some changes but it has melting point and solidification in a limited range.
Bowden Extruder and Direct Drive extruder are the two of the most common extruders in the 3D printing industry. For the sake of simplicity, we will discuss Bowden Extruder in this post.
What are the parts of an extruder? The main parts of an extruder are Drive-Gear and Nozzle (Hot End). Both of them are further divided into subparts. There are many other subparts of both of them, they are discussed in detail in the post further.
Types of Extruder For FDM 3D Printer
FDM 3D printer Extruder has two main types:-
- Bowden Extruder
- Direct Drive Extruder
Both extruders have different mechanisms for push and pull the filament and both have different positions of hot-ends. They have different advantages and disadvantages. We will discuss all parts in the post one by one.
Bowden Extruder
This type of extruder has two units: one is for pushing and pulling of filament, and another is for melting and extruding molten filament.
Direct Drive Extruder
This type of extruder is assembled in a single piece, the motor is mounted on top of the hot end it combines in one single unit. Where users required high-speed extrusion and retraction direct-drive extruders are used but they also add more weight to the moving x-axis.
Bowden Extruder Parts
Some peoples say that extruder is the drive gear part only while say that it also includes the hot-end part. We will take both parts in explanation to fully explain the process.
- Drive-Gear (Cold End)
- Extrusion Gear
- Dual Flenged Bearing
- Spring Arm
- Bowden Tube
- Nozzle Area (Hot End)
- Heat Sink
- Heat Break
- Heating Block
- Ceramic Heater Cartridge
- Nozzle
- Thermistor
- Nozzle (Although it comes under heating block in Nozzle area but it is a important part so we will discuss it seperately.)
- Cooling Fan
An FDM 3d printer extruder has two parts on the temperature basis the cold end(Drive Gear) and the hot end (nozzle). As we guess from the name in the cold end every part is at its normal temperature and on the hot end parts are not at their normal temperature.
In Cold End, a multiple teeth metal Extrusion gear is attached to the shaft of the stepper motor, and a dual flanged bearing is attached to a spring-loaded aluminum arm. Which always put the same amount of pressure on the filament so the filament did not slip from the metal gear.
Extruder Drive-Gear Sub-Parts
Extrusion Gear has an important role in smooth print. It is the part that pushes your filament in the hot end and provides enough force to extrude the material. If extrusion gear is damaged or did not fit well on the stepper motor shaft it slips from the filament and your print may get worse due to slip of gear on filament create under extrusion problems.
Extrusion gears come in many different designs according to their use. Each design has Pros and Cons. In most, desktop 3d printers 20 or 16 teeth extrusion gear is used.
Dual Flanged Bearing
It provides counterforce for extrusion gear to make a good contact area with the filament. In nowadays manufacturers provide dual gear extrusion in which the bearing is replaced with another extrusion gear that drives through the same motor so it will provide more force over filament.
Spring Arm
It is a piece of aluminum but is necessary for the proper working of the extruder. It provides a platform to connect the bearing also it transfer spring force to the bearing which pushes the filament toward extrusion gear for good contact.
Bowden Tube
It is used for two main reasons which are that it provides a guideway for filament between cold-end and hot-end and another reason is that it does not allow the filament to move wherein the air except towards the hot end. Bowden Tube is also smooth so the filament smoothly flows between cold end and hot end.
Note:- Bowden Tube is mostly used in Bowden type extruder but if you want to directly use your filament from dry-box without open it to protect it from moisture so you connect Bowden tube between cold-end and dry-box because it also provides an airtight seal if you use correct Bowden connector.
Nozzle Area of Extruder
In the nozzle or hot end, the filament is melt with the help of a heater. Hotend has multiple parts that do different work to in a smooth flow thus you got the good print. One of its main parts is the nozzle so we commonly say it nozzle area of the extruder.
Nozzle Area Sub-Parts
Heat Sink
The heat sink is the upper part of the hot end. It is the entry point of filament from where the filament enters the hot end and guides the filament towards the heat block through a heat brake pipe. It also has a fan which helps him to be cool during the operation of the machine.
Heat Break
Heat Break is the outer threaded pipe that has a PEEK layer and PTFE Tube for guiding the filament toward heat block smoothly also it stops the heat from entering the heat sink. Generally, the heat break pipe is made of non-heat conducting material but now some manufactures also provide bi-metallic heat break which has different material in a different section of assembly which increase the non-conductivity of the heat break.
Heating Block
The Heating Block has multiple parts in one assembly. It has a heater cartridge that heats the filament so it can melt. Heat blocks also have a thermistor whose resistance changes with change in temperature by reading the resistance computer know the correct temperature of the heat block and the most important heat block has a nozzle that is screwed in it.
Nozzle Heat-Block Sub-Parts
Ceramic Heater Cartridge
Ceramic Heater Cartridge is the source of the heat energy in the extruder which provides enough heat to melt the filament. It also comes in a much different power rating. In the cartridge heater, nickel-chrome resistance wire is wind around the magnesium oxide core which is in the cylindrical alloy case and case fill with magnesium oxide for better heat transfer. Never use exceeded power rating heater because it will cause damage to the printer or accident.
Nozzle
The Nozzle is the party that takes the heat and melts the filament and extrudes the molten plastic. It also comes in many different shape sizes, Internal geometry, and different Material type. In abrasive type material, you had to use stainless steel nozzle or any other hardened metal nozzle but for normal print material, you use a copper nozzle or brass nozzle.
Thermistor
A Thermistor is a temperature-sensitive component it helps the computer to know the correct temperature of the heat- block to control the process of the extrusion for even flow. Thermistor resistance changes with change in temperature this value may differ for different kinds of manufactures but the working principle is the same.
Cooling Fan
Layer Cooling Fan is also part of the hot-end but works for cooling the extruded material from the nozzle to ensure that the next layer will deposit securely on the previous layer. For better working of the layer cooling fan, people add airflow guidance tunnel to make an air flow below nozzle at the correct height. You can print these guidance tunnels.
FAQ – Extruder Parts
A Bowden extruder is mainly made up of 2 parts i.e. the drive gear (cold-end), the nozzle area (hot-end), and a layer cooling fan.
To control the temperature of the nozzle, the extruder uses a thermistor which changes its temperature by changing the resistance according to the set values.
Conclusion
In this post, we have covered all the parts and subparts of a Bowden Extruder for FDM 3D printing. Still, if anything is left or you have any doubt please ask in the comment box.
Share it with your 3D printing community, we are waiting for your feedback. Thank You.
