Researchers atRutgers University和theUniversity of Louisvillehave developed a Fused Filament Fabrication (FFF) system that’s capable of using multiple nozzles to rapidly 3D print different areas of the same part on a single gantry. The 3D printer is double the speed of standard FFF.
使用内部开发的切片机，多路复用的FFF或“ MF3”机器能够同时部署两个或多个打印头，而无需其他巨枪以单独控制它们。在这样做的过程中，团队表示，MF3可以使不规则的构建，较大的连续物体以及多个较小的部分的创建，其分辨率和比较技术的速度是两倍。
该研究的主要作者杰里米·克莱曼（Jeremy Cleeman）说：“ MF3将改变热塑性印刷的方式。”“我们有更多的测试来了解我们可以制造的零件的强度和几何潜力，但是只要这些要素在那里，我们相信这可能会改变行业的游戏规则。”
Industrial FFF 3D printing’s tradeoff
According to the researchers, FFF continues to show potential as a cheaper and better-suited alternative to 3D printing large parts than powder or vat-based technologies. With the likes of泰坦机器人技术通过负载颗粒的大幅面获得市场牵引力Atlas 雷电竞app下载3D打印机, those familiar with FFF will know the process is already being scaled.
Oak Ridge National Laboratory’sresearch intoBig Area Additive Manufacturing(BAAM) has also given rise to a high flow-rate extruder and large nozzle-based approach, to upping FFF’s print speed. The technology uses a screw-based gantry-mounted extruder to melt and extrude pellets through a nozzle at flow rates of 3,000–8,000 mm3/s，具有5-8毫米宽的道路，设计可促进更快的流动。
However, the team says that matching this high throughput with the resolution needed to achieve fine features continues to prove difficult. While increasing road size (i.e., the size of extruded material beads) to raise throughput results in poor geometric fidelity, reducing road size to achieve high fidelity limits the volume of parts that can be produced.
One way that manufacturers have previously attempted to overcome this tradeoff is by overprinting the part and machining excess material away, but this can be a costly and time-consuming task. Another approach that continues to gain traction is Independent Dual Extrusion (IDEX) technology, a process in which multiple nozzles are used to print different sections of the same part simultaneously.
这样的技术将多个挤出机安装到一个龙门上，可以在同一台机器上同时生产双零件。就是说，尽管该技术是由FlashForge和Raise3D研究人员说，目前它仅限于定期几何形状。该团队还声称，每个挤出机使用一个龙门机只能使两个打印头在IDEX设置中可行。
Multiplexed Fused Filament Fabrication
为了克服现有FFF技术的缺点，研究人员提出了自己的系统，这些系统由单个三轴笛卡尔省的三个现成的挤出机组成。与当前的IDEX机器不同，由于选择性沉积方法，MF3的打印头能够同时创建零件的不同部分。
The team’s technique is made possible by a custom slicer, which is designed to optimize the movements of their machine’s gantry arms, and determine whether or not nozzles should be activated. In practice, this sees the software precisely control the direction and speed of the printer’s stepper motors in a way that allows the filament to be advanced or retracted into the extruder’s liquefiers independently.
Given that each nozzle’s speed isn’t dependent on whether they deposit material, the unit can print parts continuously while avoiding any potential overlap or collisions. The MF3’s concurrent deposition capabilities also enable the creation of parts at a higher resolution and throughput than single-extruder systems, as well as multi-material builds.
In fact, during testing, the machine proved capable of producing parts with 2.5-4 times the resolution of BAAM, and with the incorporation of further nozzles, the team says it could be significantly quicker too. Further experimentation also saw the researchers use their toolpath strategy to concurrently 3D print both large and small parts on the same bed in a way that was estimated to halve their lead times.
Moving forwards, the engineers believe the throughput advantage of MF3 over single-nozzle printing will prove to be greater for larger batch sizes. Thus it could soon allow users to “overcome the reach-driven geometric limitations” of existing technologies and “realize new economies of scale and productivity.”
Advancing high-speed FFF 3D printing
FFF continues to be the subject of significant research into improving its speed and performance. In the past, Titan Robotics has worked withAutodesk开发一个five-printhead Cronus 3D printerwith similar goals to the MF3. When unveiled in 2016, the system proved capable of using multiple extruders to simultaneously print an object, however, little has been heard about it on the development front since.
More recently, in February 2021,3D系统揭示它正在与Jabilto launch a高通量Roadrunner 3D打印机。该系统具有印刷高温细丝的能力，可充当其高速融合（HSF）平台的基础，并针对汽车和航空航天扇区。
在其他地方，研究人员南特大学已经开始调查heat transfer and adhesion during FFF 3D printing。通过量化在此过程中发生的热交换，研究人员试图识别最佳的打印参数集，并最大程度地提高3D打印零件的机械性能。
The researchers’ findings are detailed in their paper titled “可扩展的、灵活的和有弹性的并行of fused filament fabrication: Breaking endemic tradeoffs in material extrusion additive manufacturing,” which was co-authored by Jerem Cleeman Alex Bogut, Brijesh Mangrolia, Adeline Ripberger, Kunal Kate, Qingze Zou and Rajiv Malhotra.
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Featured image shows a diagram indicating how the MF3 operates. Image via Rutgers University and the University of Louisville.
