At the height of additive manufacturing’s growth, a promise was made to advance 3D printing technology and enable anyone to produce anything anywhere. BigRep is proud to have developed the revolutionary Metering Extruder Technology (MXT®) to finally realize that promise and provide industrial manufacturers of any size the dependable tools they need to produce without limits.
As FFF extrusion technology reaches the peak of its development cycle, it becomes less likely that the technology’s quality will meaningfully improve. Additive manufacturing must be rethought from its foundation, the extruder, to achieve the long-sought goals of repeatable end-use parts with engineering-grade materials.
Featured on the BigRep PRO large-format 3D printer, MXT has taken on the challenge of professional industrial production, setting a new additive manufacturing standard.
How Does it Work?
If FFF 3D printing is like a hot-glue gun, MXT is a syringe.
In the FFF process material is melted as it passes through an extruder’s hot end. Unlike FFF, MXT melts filament in advance and stores it in an internal reservoir. This extra step enables unprecedented speed and precision in the printing process by working with material that is stored at its ideal temperature and viscosity.
Using a reservoir of molten filament allows MXT to print with unprecedented control due to the separation of filament melting and material deposition processes. Traditional FFF technologies push solid filament through extruders by exerting force at a distance from the hot end, creating a gap of time between the cease of force and of actual filament extrusion. Instead, MXT uses a metering pump just above the hot end as a source of controlled, local force for the pre-emptively melted filament. With this highly accurate feeding combination, MXT pushes an intricately measured volume of material through the hot end locally. This drastically improves printer throughput and precision, enabling better results at a faster pace.
The process makes printing up to five times faster than traditional FFF printers, depending on part geometry and layer height, with a throughput of up to 200 cubic centimeters per hour (cm3/h) at maximum extrusion rate. Because of its level of accuracy and separated material processes, MXT extruders eliminate many of the limitations of FFF 3D printing , improving speed, geometric accuracy, and repeatability.
MXT also eliminates oozing – excess material passing through the nozzle after the extruder stops pushing filament through – by implementing a secondary force called retraction where the extruder’s metering pump runs in reverse to pull or stop any filament already past the reservoir, halting extrusion instantly to maintain exceptional print accuracy.
Why Does it Matter?
With traditional FFF extruders, speed is limited by the necessity of melting filament as it passes through the hot end. If material is pushed through too quickly it won’t melt enough to effectively adhere to previous layers and users risk delamination – layers of printed parts separating. This creates a bottleneck where extruders are forced to match pace with the speed their hot end can properly melt filament at. By separating these processes, heating filament to ideal extrusion temperature in the reservoir, MXT avoids the issue entirely and improves all aspects of printer performance.
Upon announcing MXT, Fabbaloo’s Kerry Stevenson called it “the single most important advance in 3D printer extrusion technology I’ve yet seen.” It’s an advancement that will enable the industry to continue its exponential improvement of additive hardware – making printing faster, better quality, with more materials.
As FFF extrusion technology reaches the peak of its development cycle, changing the technology’s foundation – extruders – becomes the only way to continue advancing additive capabilities and industry applications.
Repeatability, speed, and precision can only be further improved upon by forgoing the traditional FFF printing process and instead reinventing extrusion processes from the group up.