Tech Breakdown: The Bondtech QR Universal Extruder
Posted on Oct. 6, 2016 by MatterHackers
Our engineers examine this easy printer upgrade to learn how it can eliminate under extrusion, gear grinding, and filament slippage. 

The cause of bad 3D prints can often be traced back to the printer’s extruder. Many issues such as under extrusion, filament slippage, deformation and gear grinding are the direct result of poorly designed and constructed extruders. The Bondtech QR Universal Extruder (1.75mm and 3.00mm) makes all of these issues fade to a distant memory.

Overview

Upon examination of the Bondtech QR extruder, one quickly recognizes the high quality construction. The gearbox and drive gears are fabricated with hardened, CNC machined components coupled with a housing made from sintered 3D printed polyamide (nylon). The nylon housing provides stiffness, heat resistance and is tightly integrated with the main gearbox assembly. The Bondtech QR extruder features a DualDrive gear system (see Figure 1) that consists of two counter rotating drive gears integrated into a planetary gearbox. The attention to detail is readily apparent in the precision of the resulting 3D printed parts.

Figure 1: Dual Drive Gear System


The QR acronym of the Bondtech QR extruder refers to the Quick Release lever (see Figure 2) that allows for quick loading and unloading of filament. This feature is a time saver when working with any type of Bowden configuration. Speaking of the Bowden configuration, the Bondtech QR extruder works with both Bowden and Direct extrusion set-ups (see Figure 3). The Bondtech QR extruder uses the Groove Mount standard (see Figure 4) which allows for direct placement of E3D hot ends or Bowden adaptors. The QR lever is also where the tension knob is located. This knob allows for easy and dynamic adjustment of filament tension. Good filament tension provides additional stability to the entire extrusion ecosystem.

Figure 2: View of the Quick Release Lever


Figure 3: Direct Drive and Bowden Configurations


Figure 4: View of the Groove Mount


Test Results

Our test results can be summed up in two words - performance and reliability. Robust and ruggedly constructed, the Bondtech QR extruder reliably handles any filament in any configuration, even flexible filaments in a Bowden configuration. This produces consistent results in printed parts. The knock against 3D printers in the past was that the same printer could not produce the same quality component over a series of iterations. The Bondtech QR takes care of the uncertainty in the filament deposition side of the printing equation.

So how is the Bondtech QR extruder able to produce this consistency and reliability? The key is in the DualDrive gear system (see Figure 1) that firmly grips the filament from both sides. Typical extruders only grip the filament from one side, and have a smooth idler on the other side to apply pressure against the drive gear. By using two drive gears and gripping from both sides of the filament, the extrusion force is literally doubled. Also, the entire filament path, from entrance to exit, is fully constrained (see Figure 5). This means that there is virtually no chance for filament shifting, slippage or deformation during the extrusion process. This constrained pathway and DualDrive gear system provides high extrusion force and precision filament flow. As a result, any extruder “clicking” or grinding problems that may emerge are directly related to a clogged nozzle.

Figure 5: View of Filament Pathway


Perhaps most importantly, the Bondtech QR extruder is easy to use and maintain. Should one need access to the gears, only two bolts and the tensioner knob (see Figure 6) hold the gear assembly together. This allows for removal of accumulated filament debris as the filament moves through the extruder assembly.

Figure 6: View of End Bolts and Tensioner Knob


So are there any negatives? There are none with the Bondtech QR extruder directly. The extruder performed flawlessly in all of our use cases. One detractor is in the weight of the gearbox motor (see Figure 7). This might provide some wear on a Cartesian Coordinate printer’s gantry in a direct drive configuration. Also, extruder mounts will have to be fabricated by the end user. However, we at MatterHackers have free downloads of Bondtech QR extruder mounts for a number of common printers. These mounts may be found at Bondtech QR Extruder Mount for Ultimaker 2Bondtech QR Extruder Mount for Standard PrinterBondtech QR Extruder Mount for Rostock MAX and Bondtech QR Extruder Mount Dual Extruder for Lulzbot TAZ 5 and 6.

Figure 7: View of the Gearbox Motor


Final Takeaway

Just remember that poorly designed and fabricated extruders can play havoc in the 3D printing domain. Bad extruders waste print time, waste materials, often cause mid-print failure and may even damage the printer. Take much of the worry out of 3D printing by replacing your existing extruder with the Bondtech QR Universal Extruder (1.75mm and 3.00mm). Its precision and reliability will put an end to your frustration and bring back the fun in 3D printing.


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