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A team of researchers from诺瓦大学里斯本已经开发了一种新形式的电弧添加剂制造（WAAM），该制造专门为小零件和精美雷电竞充值的功能细节设计。
Named µ-WAAM, the high-precision 3D printing technology utilizes metal wire materials with a diameter of just 250µm. For context, conventional WAAM typically uses wire diameters of above 1mm. It aims to offer both precision and print speed, combining the resolution of powder bed fusion (PBF) with the deposition rates and material efficiency of traditional WAAM.
根据Nova研究人员的说法，新的µ-WAAM方法特别适合于大规模WAAM所困扰的薄壁和其他复杂结构的制造。
PBF versus WAAM 3D printing
如果您正在寻找较小的金属组件，那么PBF是3D打印技术。该方法利用激光或电子束在粉末床上融化并融合粉末状的原料，在每一层后重新涂抹和重印以制造实心3D零件。由于使用了斑点激光器，PBF具有很高的几何精度，但由于低沉积速率和高粉末浪费而阻止。
On the other hand, those seeking larger part production might find it useful to opt for a wire-feed directed energy deposition (DED) process instead. While it does suffer from poor printing resolution, WAAM boasts relatively high material deposition rates, making it great for large part applications in industries such as maritime.
The µ-WAAM 3D printer
为了结合两全其美的最好，Nova研究人员开发了带有小型龙门系统的定制µ-WAAM电弧火炬。就像一台普通的FFF机器一样，µ-WAAM打印机基于笛卡尔坐标系，并利用线性轴承和常规的步进电动机。
According to the team, the wire feed device was inspired by the filament extruders found in FFF 3D printers. One drive gear is actuated by a stepper motor compressed under a radial bearing.
为了与电线馈电建立电动接触，团队使用了0.3mm的黄铜喷嘴。此外，将标准的12V/100AH电池用作电源。在这种情况下，需要电池，因为传统的焊接源根本无法提供足够的I-V特性来产生如此小的焊接弧。NOVA研究人员甚至集成了基于氩气的屏蔽气体，以避免过程引起的缺陷，例如孔，同时保护电线材料免受氧化的影响。
So how did it stack up? To test the µ-WAAM 3D printer, the team had it print out a number of thin wall structures using steel wire. Where PBF can only achieve build rates of around 2g/min, µ-WAAM clocked in at up to 5g/min. This still doesn’t hold a candle up to the deposition rate of conventional WAAM, which can be around 18.5g/min, but is impressive given the size of the custom system.
When it comes to dimensional precision, WAAM may only deliver accuracies of ±0.7mm, which is why extensive post-processing is necessary to achieve high-quality surface finishes. On the other hand, the µ-WAAM process managed to achieve a dimensional precision of less than 0.3mm. Again, this isn’t as precise as PBF (±0.04mm), but provides a nice jack-of-all-trades middle ground between the two conventional technologies.
Ultimately, the work successfully validated a new variant of WAAM, scaling the technology down to suit finer feature details and thin walls. The µ-WAAM approach is by no means perfect, but it bridges the benefits of both PBF and WAAM, addressing some of the pain points of each.
Further details of the study can be found in the paper titled ‘Micro Wire and Arc Additive Manufacturing (µ-WAAM)’.
上个月，在类似的研究中，美国的工程师California State University, Los Angelesand TurkishEskisehir Osmangazi Universitydeveloped alow-cost WAAM 3D printer that can be built for just $1,000. By integrating gas tungsten arc welding (GTAW) technology into an FDM-like gantry setup, the researchers were able to create a machine that doesn’t rely on complex robotic arms, allowing them to keep it affordable and open-source.
In industry,MX3D, a developer of metal WAAM technology, recently unveiled its newpartly 3D printed ‘WAAM Clamp’. The hybrid industrial part is an example of a pipeline clamp, a component used to seal high-pressure leaks in the chemical and oil and gas sectors. Weighing in at 87kg (30kg of which was 3D printed), the WAAM Clamp took 45 hours to manufacture.
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Featured image shows large parts 3D printed via WAAM. Photo via WAAM3D Ltd.
