Wire Arc Additive Manufacturing (WAAM) has emerged as a revolutionary production process within the realm of 3D printing and metal part repair. As a member of the Direct Energy Deposition (DED) family, WAAM utilizes a welding robot in tandem with Gas Metal Arc Welding (GMAW) and additive manufacturing techniques to deposit layers of metal, creating intricate 3D shapes.
Advantages of WAAM
WAAM stands out for its various advantages over traditional manufacturing processes, and other DED methods:
- Large Size: WAAM’s capability to manufacture parts exceeding a cubic meter in size is a distinct advantage. The use of robot tracks and welding manipulators further extends the potential printable dimensions.
- Design Freedom: Additive manufacturing methods, including WAAM, provide the freedom to manufacture complex shapes. This facilitates topological optimization and the production of generatively designed parts, offering designers greater flexibility.
- Low Start-up Cost: Compared to alternative DED systems, WAAM boasts a relatively lower start-up cost. Its higher deposition rate, in conjunction with cost-effectiveness, contributes to its economic appeal.
- Wide Material Availability: WAAM employs a consumable wire as feedstock, enabling the use of a variety of alloys in wire form. This versatility allows for the selection of materials with diverse mechanical properties, enhancing the design possibilities.
- Hybrid Manufacturing: WAAM seamlessly integrates with other production methods, providing the flexibility to add specific features to traditionally manufactured parts.
- Combined Materials: WAAM enables the design of functionally graded components, allowing the combination of multiple materials in a single part. This opens avenues for innovative designs, such as the fusion of cobalt alloy Stellite 6 and ferroalloy AISI 316L.
- Waste Reduction: Precision in material deposition minimizes waste, potentially reducing it by 50%. This is particularly relevant for parts traditionally milled from solid blocks or made from expensive materials like titanium.
- Mechanical Properties: WAAM surpasses the mechanical properties of conventional manufacturing processes such as casting and forging, offering enhanced performance.
WAAM for Metal Part Repair
Beyond its role in manufacturing, WAAM finds application in the repair of metal parts prone to wear, such as rails, rotors, and dies. The process automates tedious and labor-intensive repair tasks, introducing efficiency through monitoring and control mechanisms.
Post Processing
While WAAM introduces innovative capabilities, post-processing remains crucial to address side-effects. Residual stresses and surface roughness are inherent in WAAM processes, necessitating specific steps:
- Stress Relief Treatment: To mitigate residual stresses, a stress relief treatment is applied post-printing. Elevated temperatures during this treatment enhance the part’s performance and lifespan, reducing the risk of premature failure.
- Surface Finishing: Layered construction in WAAM results in visible surfaces. Optimal fatigue life, tensile behavior, and corrosion resistance are achieved through surface finishing methods like milling or grinding.
Conclusion
Wire Arc Additive Manufacturing emerges as a transformative force in metal production, combining the strengths of welding and additive manufacturing. Its versatility, cost-effectiveness, and potential for large-scale production make it a promising technology, shaping the future of metal fabrication.