< Resources

WAAM 101

An introduction to Wire Arc Additive Manufacturing

Wire Arc Additive Manufacturing (WAAM) is a production process used to 3D print or repair metal parts. It belongs to the Direct Energy Deposition (DED) family of Additive Manufacturing processes. WAAM is executed by depositing layers of metal on top of each other, until a desired 3d shape is created. It is a combination of two production processes: Gas Metal Arc Welding (GMAW) and additive manufacturing. GMAW is a welding process used for joining metal parts using an electric arc, and additive manufacturing is the industrial term for 3D printing. The production of parts using WAAM is carried out by a welding robot integrated with a power source. A welding torch attached to the robot is used to melt the wire feedstock to build 3D parts.

RAMLAB ded_Dark Wire Arc Additive Manufacturing
AISI 316L 3D printing WAAM
Advantages of WAAM

Compared to conventional manufacturing processes like metal casting and forging, WAAM and other additive manufacturing processes have been around for a relatively short time. WAAM outperforms conventional manufacturing processes and other DED techniques in a number of ways. These advantages are elaborated in the following points:

  • Large size
    The maximum printable size primarily depends on the reach of the welding robot that is used. WAAM offers the capability of manufacturing parts with dimensions over a cubic meter. The maximum printable dimensions can be increased by using robot tracks and welding manipulators.
  • Additional design freedom
    WAAM and other additive manufacturing methods allow for the manufacturing of relatively complex shapes. This also means that topological optimization and the production of generative designed parts become more accessible.
  • Low start-up cost
    Compared to other DED systems like direct metal laser sintering or electron beam additive manufacturing, WAAM offers a relatively lower cost. Additionally, WAAM offers a higher deposition rate compared to other AM techniques, which also contributes to the cost effectiveness of the process.
  • Wide material availability
    WAAM uses a consumable wire as its feedstock. Depending on the application, a multitude of alloys are available in wire form. This offers a wide range of materials and mechanical properties to design and manufacture a part.
  • Hybrid manufacturing
    WAAM can be used in combination with other production methods, to add specific features to traditionally manufactured parts.
  • Combined materials
    WAAM offers the possibility of designing functionally graded components, where multiple materials can be combined to design a part, for e.g cobalt alloy Stellite 6 and ferroalloy AISI 316L.
  • Waste reduction
    Material is only deposited where needed, which can potentially lead to a waste reduction of 50%. This is especially relevant for parts that conventionally are milled out of solid blocks and/or parts that are made out of costly materials, for example titanium. Topological optimization can maximize efficiency in the use of materials.
  • Mechanical properties
    WAAM can outperform the mechanical properties of conventional manufacturing processes like casting and forging. Learn more about the mechanical properties of WAAM parts in the materials library.
WAAM Materials Titanium Ti6Al4V Additive manufacturing
Post processing

Most WAAM processes need some form of post processing. This is a necessary step to address the side-effects of WAAM: Residual stresses and the surface roughness. 

To reduce the residual stresses in the part, a stress relief treatment is applied after printing. This treatment is done at an elevated temperature to reduce the risk of premature failure and increase the performance and life-span of the part. In some cases a specific heat treatments is applied to adjust the material properties.

Surface finishing is the second most important post processing step in WAAM. Every WAAM part is built in layers, which is visible on the surface. In order to optimize the fatigue life, the tensile behavior and the corrosion resistance, it is important to adopt a finishing process like milling or grinding.

Nederland, Rotterdam, 2016.RDM, Heijplaat, het nieuwe fieldlab waar het Havenbedrijf in investeert. nieuwe 3D printer, 3D geprinte sokkel en lasrobot Foto: Freek van Arkel
Equipment used

RAMLAB uses multiple Valk welding systems with MaxQ to perform WAAM activities. These systems consist of a robotic arm and peripherals like shielding gas, tracks, manipulators and gates. Most of the robotic arms used at RAMLAB are from the Panasonic TAWERS series. 

Over the years, several adjustments and additions to the welding system have been made to increase the stability of the welding process and to deal with the challenges that come with WAAM. Examples of these challenges are temperature and heat input control, geometry mismatches, workflow and automation. The solutions to these challenges have been brought together in MaxQ: the monitoring and control system developed by RAMLAB. Go to the MaxQ page to learn more about MaxQ’s features.

Repair WAAM DED welding path planning robot machine
Software

At RAMLAB, Autodesk’s software products PowerShape and PowerMill are used for creating CAD and CAM files. PowerShape is used for the (re)design of components for WAAM. PowerMill is used for toolpath planning and simulation. The toolpath that is made with PowerMill can be uploaded directly to the MaxQ app using a web browser, from where production is initiated.

WAAM resolution
Materials

In theory every material that can be welded, can also be used for WAAM. In practice however, every new material needs testing and optimization of the wire feedstock to reliably manufacture parts. To improve the quality of the WAAM process and materials, RAMLAB works together with partners. A wide range of materials has already been tested and used in production. A selection of these materials and their mechanical properties can be found in the materials library.

WAAM Materials S420 Additive manufacturing
Applications

WAAM, welding and repair can be applied in a range of fields, from marine to aerospace, chemical industry, energy, automotive, high tech, and oil & gas. WAAM especially outperforms other production methods when material savings, increased material performance, reduced lead times and manufacturing of high-end materials are key factors for the business cases.

In the past three years RAMLAB has focused part of its efforts on the application of the WAAM process to the repair and refurbishing of molds and dies. WAAM can reduce the cost of repairing these tools significantly, by automating the process, increasing the service, while reducing human contact with fumes.

Get in contact