Engineers at the US-basedCalifornia State University, Los Angelesand TurkishEskisehir Osmangazi Universityhave developed a low-cost wire arc additive manufacturing (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 have been able to create a machine that doesn’t rely on complex robotic arms, allowing them to keep it affordable and open-source, while initial testing has revealed its compatibility with both carbon steel and Inconel 718.
“The proposed system, together with proper process parameters, can be used with many metallic alloys that can be processed by GTAW and WAAM, with less effort and lower cost compared to the expensive powder bed systems,” said the team in their paper. “Some examples of the alloys that can be processed include titanium, aluminum, nickel and cobalt-based superalloys, and low-alloy steels.”
Adopting Gas Tungsten Arc Welding
Particularly in the aerospace and automotive sectors, metal 3D printing technologies such as powder bed fusion (PBF) and direct energy deposition (DED), are beginning to demonstrate significant advantages over conventional subtractive processes. Using PBF, for instance, it’s now possible to produce intricate objects with internal passages and high-res features, however the researchers say that such systems also tend to be expensive and complicated to operate.
Likewise, the engineers acknowledge the large build volumes and component repair capabilities associated with DED machines, but maintain that the technology relies on costly lasers and robotics, and resulting parts need extensive post-processing.
Of the conventional metal 3D printing processes out there, the team reserves particular praise for GTAW, an approach in which an electric arc is used to melt wire feedstock into desired shapes in an inert atmosphere. When used within an AM system the technology is harnessed in the DED technology category, such setups have become popular in research circles due to their affordable semi-automatic wire feed systems, and broad alloy compatibility.
然而,尽管有这些好处,开发一个有效ve low-cost GTAW AM system can be a perilous task, in which the use of unstable parameters can lead to the creation of defective parts or cause safety complications. Undeterred, the US-Turkish team has now come up with a novel way of driving down the cost of WAAM machines, by building one in a 3-axis configuration, and set about testing its efficacy.
WAAM 3D打印为人民
由微控制器，TIG焊机和专门设计的零件组成，例如外框架上的定制自动馈线，该团队的GTAW系统的外观类似于许多商业笛卡尔FDM 3D打印机的外观。但是，该团队实际上是从头开始对其进行了加工的，而不是购买设备的支架，将其与通过Astratocaster电吉他asysU-plus machine.
在这样做的过程中，研究人员发现，他们能够将其构建成本降至1,000美元左右，不包括用于维持和编程的汽油容器和计算机。一旦他们建立了原型，该团队就继续进行测试，在这种情况下，它可以从开源Arduino MicroController中接收指令，并创建具有5-150安培的钨弧。
但是，GTAW AM系统还遇到了各种磨牙问题，例如由于进料速率波动和火炬过热，零件软化，表面波浪和形状逐渐变细。尽管该团队已经引入了一些解决这些问题的修复程序，但他们承认，火炬，层和电线馈线之间的角度仍需要不断调整，而畸形零件仍然是一个问题。
Moving forwards, the engineers say that some of their machine’s problems can be overcome by fitting it with an additional inert gas-filled shielding chamber that prevents metals from being atmospherically interfered with, and given that it can be run automatically, they maintain it can be made safe-to-operate for everyday users too, despite the extremely bright and hot arc generated during production.
“In this study, we designed a low-cost wire-arc additive manufacturing system that offers an alternative solution to develop and repair high-value metallic components,” concluded the team in their paper. “The [machine’s] applications include the repair and manufacture of parts such as fittings, implants and heat exchangers in the aviation, automobile and medical industries.”
WAAM的重型申请
Over the last two years, WAAM’s ability to 3D print ultra-robust parts has increasingly been put to the test within maritime, defense and experimental infrastructure applications. Late last year, robotic metal 3D printing firmMX3Drevealed that it had used the technology to create a独特的“骨骼地板”for a prototype欧洲航天局lunar settlement.
Just before MX3D’s WAAM excursion, heavy equipment manufacturerHuismanalso announced that it had deployed the technology to3D print four crane hooks. Measuring 1.7 x 1.3 meters across, and weighing in at a hefty 1,700 kg, each of the large-format prints is capable of lifting up to 350 metric tons in weight.
Similarly, in other maritime applications, WAAM has been used by the likes of the French firmNaval Group, to manufacture a空心螺旋桨刀片演示器. Built from stainless steel in less than 100 hours, the 300 kg print was successfully tested against fatigue and corrosion, with its hydrodynamic properties also being assessed via numerical simulation.
The researchers’ findings are detailed in their paper titled “Development of a Low-Cost Wire Arc Additive Manufacturing System,” which was co-authored by Miguel Navarro, Amer Matar, Seyid Fehmi Diltemiz and Mohsen Eshraghi.
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Featured image shows the researchers’ prototype gantry-mounted WAAM 3D printer. Photo via the Journal of Manufacturing and Materials Processing.
