Without an extruder, there would be no way to pass on the filament at an optimum temperature to make a 3D model. So, needless to say, it is undeniably one of the most crucial parts of any 3D printer.
Between the two major types of such extruders, Bowden stands out with its special PTFE tube. Because of the extra pressure, the filament passes on more smoothly and efficiently.
So here we are, to discuss how you can have the best Bowden extruder experience.
What is Bowden Extruder?
Bowen extruder refers to the mechanism through which a 3D printing filament is fed into the printer through a long tube reaching the hot end.
This tube is typically made of Teflon or PTFE (poly-tetra-fluoro-ethylene) which makes it quite flexible and convenient to work with.
Because of the tube, the filament gets to reach the other end smoothly. Especially in a Bowden extruder, it plays a bigger role by generating just enough pressure to push the filament in the right direction.
How Is Bowden Extruder Different From Standard Extruder?
The main difference between the standard extrusion mechanism and Bowden lies in the placement of drive gears. Instead of the usual direct drive approach,
the Bowden extruder separates drive gear from the hot end. In Bowden, a special tube connects the far-away motor to the hot end.
Utilizing this method, the user can generate 3D models faster without sacrificing their quality. Even though the filament has to cover a longer distance in this mechanism,
the inner diameter of the PTFE tube narrows down its path and exerts pressure from the cold end. The print head can then produce the layers faster.
3D Printer Bowden Extruder Setup
Just like most other devices of its kind, the 3D printer Bowden extruder setup primarily consists of two parts – hot end and cold end.
Even though the hot end is often not thought of as part of the extruder, we are going to include it in the extruder setup discussion to explain the process clearly.
Motors or stepper motors help 3D printers to guide their extruder along the three axes – x, y and z. They can offer many other advantages according to the kind of printer or extruder they are associated with.
Most desktop printers using Bowden extruders use the stepper motor NEMA 17. Other varieties include NEMA 14, NEMA 23 and NEMA 24.
They can be geared, or designed to go 0.9-1.8 degrees per step. They differ in terms of length, torque, voltage rating and current rating as well to suit different kinds of 3D printers.
2. Drive Gear
The drive gear helps to hold the filament that has just been inserted into the cold end and then to push it further so that it can reach the print bed.
Similar to the motor, the drive gear also comes in many varieties. Typically, the top two types you will find are hobbed and hobbed bolts.
The idler or idler wheel is a round bearing required to push the filament into the drive wheel. To make this mechanism work successfully, it needs the support of other components like PTFE tubing, bearings, rubber wheels and printed plastic.
You must set up the idler to generate the right amount of pressure to avoid running into any issue during operation.
4. Bowden Tube
Bowden tube is the one made from PTFE which connects the two ends of a 3D printer. This is what makes the Bowden extruder different from the direct extruder since the latter has no tube like it.
The filament of your choice will traverse the entire distance by going through this tube.
5. Hot Nozzle
Finally, the filament gets melted and extruded through the hot nozzle where the chosen model gets built. The assembly of this hot end requires a heated chamber for melting the filament and a built plate to accumulate the melted material.
The filament goes from the cold end to a heat sink, then to the heat break made of non-heat conducting metal and then finally reaches the nozzle.
Such a setup is necessary to maintain the optimum temperature and consistency of the filament, which in turn contributes to proper extrusion and building of the model.
There are multiple upgrades you can get your hands on to improve the features of your Bowden extruder. Here we discuss four of the most popular ones:
1. Dual Gear Extruder
The Bowden modification of dual gear introduces more control on the printing process and thus makes it more reliable for regular work. However, you don’t have to worry about going through many difficulties to make this work.
All it will need is a second drive gear added to the extruder so that the filament can be pressed from both ends at the same time. As a result, it can get into the hot nozzle faster with a reduced possibility of slipping around the drive gears.
2. Capricorn Tube
Since the filament is passed to the hot end through a tube, that material can often flip-flop along the way in a Bowden extruder.
To solve this issue, you can upgrade the usual PTFE tube to a Capricorn tube which has tighter tolerances in its inner diameter. This also lowers the amount of wasted energy of the motor.
3. All-Metal Hardware Kit
To make your 3D printing system more robust, you can easily replace all the plastic parts of your extruder with aluminum parts through the upgrade of an all-metal hardware kit.
In addition to providing your setup with more stability, this Bowden extruder kit also ensures an economical price point and ease of installation.
4. Bondtech BMG
The name’s Bond, Bondtech.
Ok, bad joke.
But the Bondtech BMG is actually a good choice for a Bowden upgrade since it can bump up the overall quality of your system all by itself. Have you read the upgrades above? This one combines them all.
You can use it to press the filament from both sides and also improve it with a 3:1 gear ratio. This results in the drive gears benefiting from higher torque.
However, you will not be getting any mounting hardware with it so make sure you already have that in your possession.
Another common issue is that it can increase the motor’s temperature quite a bit. So make sure you are prepared for that before settling for this upgrade.
As you can see, you can make the best Bowden extruder even better by equipping it with new and convenient upgrades according to your needs.
Setting it up is not that difficult since its system involves a handful of primary components. Once all set, you can enjoy a smooth flow of the filament for your next 3D printing project!