What is wire arc additive manufacturing (WAAM)?

In recent years, additive manufacturing technologies have developed rapidly due to their capability of manufacturing complex components without the restriction of conventional manufacturing processes, resulting in reduction of the lead-time, material waste and costs. Nevertheless, there are still significant obstacles in the production of large-volume components particularly in the efficiency of the process. A major impediment in the application of additive manufacturing at industrial scale and its feasibility within sustainable business cases is the limitation in component dimensions and low build-up rate of commonly used powder-based methods.

Additive manufacturing is not a one size fits all approach. Mayor strives have been made in terms of designing parts for additive manufacturing applications which means adding value to a part by reducing the number of components, material, and weight.

Currently, the metal Additive Manufacturing (AM) processes are mainly powder bed fusion processes, which use a laser beam as the energy source and expensive metal powder as material. The laser-based powder fusion machines are capable of making complex shapes, but the build volume and printing speeds are limited. Also, using the metal powder as feedstock makes the process costly, environmentally hazardous and causes defects such as porosity which affects the mechanical properties of the final part. Another AM process that has attracted attention recently is wire arc additive manufacturing or WAAM.

What is wire arc additive manufacturing?

Wire arc additive manufacturing or WAAM is a process where an electric arc is used to join metals. The mature technology makes it possible to use layered printing of several metal layers in a fully automated, digital controller and easy to use manner.

Due to high build-up rates and material efficiency, wire and arc-based additive manufacturing processes are becoming increasingly important in industrial applications. In comparison to conventional manufacturing processes such as forging or milling, these technologies enable considerable savings in terms of costs and lead times that also allow economical production of large components.

GEFERTEC’s 3DMP® is one of those WAAM systems. The CNC based Arc series combines the technically mature and proven arc-welding method with the CAD drawings of the product designers and engineers in a completely new production system. Either 3 or 5 motion axes offer maximum flexibility in terms of the component volume and enable the additive production of high-quality metal parts. Commercial metal wire is deposited layer by layer to produce or repair engineering components.  The 3DMP® system is an advanced CNC system as opposed to simple robotic WAAM systems. The system can produce near net shape preforms without the need for complex tooling. Thus, offering potential for cost and lead time reduction. Performing surface engineering operations such as hard facing and repair of worn-out engineering components is also an area of application.

Gefertec process Chain
Figure 1: The GEFERTEC 3DMP® Process Chain – https://www.gefertec.de/en/3dmp-process-2/

WAAM can replace all the types of conventional manufacturing and machining methods for metal parts, such as forming, cutting, joining, coating, milling, turning, etc.

What applications are the perfect candidates for WAAM?

Applications for WAAM technology are very diverse. The following markets are seeing large benefits from using WAAM technology. Oil and gas, energy, aerospace and space, tooling, automotive and transportation. It is applicable for any low to medium complexity part which with normally have long lead times.

Wheelset Bearing Cover of Deutsche Bahn
Figure 2: Wheelset bearing printed using WAAM – https://www.gefertec.de/wp-content/uploads/2020/06/DATASHEET_DB_ENG.pdf

What materials can be used for wire arc additive manufacturing?

That is one of the other big advantages of the WAAM technology. Applicable materials are readily available in the market. Since welding technology has been around for decades, welding wires have also been widely used. Since the WAAM system used standard welding wire it is basically possible to print with any material that is in wire format and weldable. In recent year there has been a big focus on developing specific wires for the WAAM application and those are now available in the market as well.

Alloys being used range from steel alloys over aluminum, nickel based to titanium.

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