Linear arc additive manufacturing belongs to the category of directed energy deposition 3D printing. DED technology is a metal 3D printing technology that involves the deposition of metal materials into a powder or linear form via a nozzle mounted on a multi-axis arm. A focused energy source, i.e. a laser, electron beam, or plasma, is used to melt the material as it is used to build the part layer by layer. In the case of WAAM, the arc is used as a heat source, inspired by arc welding.
WAAM technology is based on the principle of various automatic welding technologies using robotic systems: metal inert gas or metal active gas, tungsten inert gas or plasma arc welding wire. There is also the cold metal transfer welding process, derived from MIG, which was created by Vonens in 2004. All kinds of metals are compatible with WAAM. These include titanium, aluminum, nickel and steel alloys.
As with other DED processes, wire-arc additive manufacturing is often used to repair equipment and copy parts that are no longer produced in order to maintain old machines. However, the technology can also be used to make complete parts. Wire arc additive manufacturing is particularly suitable for the aerospace, aerospace, automotive, energy and defense sectors. It is used for manufacturing prototypes, molds, individual parts and small series production. However, its application in mass production is still under review, although it is particularly suitable for the manufacture of large metal parts.
In the aerospace sector, for example, Naval Group uses linear arc additive manufacturing technology to manufacture propellers for the mine hunting vessel . In the energy sector, Vallourec produced the first sealing ring using wire arc additive manufacturing to ensure the safety of the EDF Hydro hydropower plant, with a diameter of 1 meter and a weight of 100 kg. In the field of robotics, MX3D has also used this technology to produce structural steel connectors. MX3D also uses wire arc additive to manufacture pipe connectors for the oil and gas industry, as well as gears and custom components for large machines. MX3D even built a bridge in Amsterdam using a wire-arc additive manufacturing process! In addition, Relativity Space used this technology to build the Terran 1 lightweight launcher. The production of plastic industrial molds is another common application.
Linear arc additive manufacturing 3D printing has many advantages. First, the printing speed is fast, which has a positive impact on production time. The cost is also lower than machines using powder bed melting technology, especially selective laser melting. Wire arc additive manufacturing technology also stands out for its ability to produce very large parts. As mentioned earlier, a variety of compatible metals are also available.
The wire-arc additive manufacturing process also has its limitations. Because it allows for faster printing speeds, the detail and dimensional accuracy of the part is less reproduced compared to the powder bed melting technology. Parts manufactured using linear arc additive manufacturing techniques may have defects such as internal pores that reduce the mechanical properties of the part, both static and fatigue. This is especially true for aluminum parts.
Residual stress is another anomaly that may occur in WAAM technology. They can cause part size and/or shape to deform, especially through crimping, warping, or layering. All of these phenomena are characterized by the layers of printed parts, whether top, bottom, or in the case of layering, deformation of all layers. These deformations are caused by very high operating temperatures and the technical properties of the material. When forces are applied to a part, they will cause the part to hold poorly.
In order to limit the occurrence of these defects, it is necessary to understand all wire arc additive manufacturing parameters in order to set them as accurately as possible. This will ensure a consistent deposit of molten metal as well as constant heat. Unwinding speed, feed speed, current, voltage, layer thickness, shielding gas flow rate and electrode spacing are all key factors to ensure smooth operation.
However, there are also technical solutions that can mitigate these anomalies. These include work hardening or rolling. This method involves applying pressure to the weld bead with a roller during the cooling phase. This reduces the porosity. In order to reduce residual stress, the material can be preheated. Note that some materials and alloys are more prone to cracking or delamination than others, such as aluminum-copper, aluminum-titanium, and aluminum-iron alloys.
As with other additive manufacturing technologies, a significant amount of post-finishing is required. Post-treatment is carried out using traditional processing techniques. In some wire-arc additive manufacturing applications, a second robot can be used for processing at the printing stage.
3D printer manufacturers using line arc additive manufacturing technology include Prodways, whose 3D printers use line arc additive manufacturing -TIG process, Norsk Titanium and its internal fast plasma deposition process, GEFERTEC, MX3D, WAAM3D and Lincoln Electric, among others.
Xi'an Guosheng Laser Technology Co., Ltd. is a high-tech enterprise specializing in R&D, manufacturing and sales of automatic laser cladding machine, high-speed laser cladding machine, laser quenching machine, laser welding machine and laser 3D printing equipment. Our products are cost-effective and sold domestically and abroad. If you're interested in our products, please contact us at bob@gshenglaser.com.