RAMLAB has successfully delivered its first manufactured titanium (Ti6Al4V) part together with Hittech for the AMable initiative, cutting down on material waste significantly. Traditional manufacturing processes, such as forging, require a machining process to reach the final shape, wasting up to 90% of material. RAMLAB developed a WAAM solution (GMAW-based) for the Ti6Al4V alloy and was able to reduce the buy-to-fly-ratio with 50%. Furthermore, the research showed the potential to reduce delivery time with several weeks.
Ti6Al4V is a titanium alloy with widespread use in many industry sectors thanks to its great material properties. With its high strength to weight ratio, corrosion resistance and biocompatibility, it is found in many aerospace, high tech, medical applications and in the chemicals processing industry.
The WAAM process parameter optimization that is executed before manufacturing a part, allows for tailoring material properties. In combination with Panasonic’s Super Active Wire Process (SAWP), a stable arc and minimum spatter were achieved. A welding enclosure and extra protective argon (Ar) ensured an inert environment with low level of contaminants.
After the process parameter optimization, the printing was physically scaled up by printing mock-ups for strategy investigation (Figure 1). The experimental phase concluded with manufacturing a solid block (or ‘pre-build’) for tensile testing in the x-y-z directions. Prior to the mechanical testing, the pre-build underwent solution treatment and ageing.
Figure 1. Scale up process from single beads to 3D printed block
Figure 2 shows the results of the mechanical testing of the pre-build. A typical anisotropic behaviour is visible in the elongation results. This can be caused by the preferential grain growth induced by the heat source. The overall result shows that the WAAM material has comparable mechanical properties with the 3Dprint AM Ti-5 wire feedstock.
Following the mechanical testing, the near-net-shape CAD model was generated by redesigning the original component. During this operation, additional material was added to allow for the machining of the final net-shape design.
Figure 2. Tensile test results on WAAM Ti6Al4V pre-build compared with 3Dprint AM Ti-5 wire feedstock in the x-y-z directions
Figure 3 shows the resulting component. Interesting to note the absence of discoloration on the entire part, a sign of a contaminants free environment. During the printing, process parameters were logged using our MaxQ monitoring and control system (figure 4) for further data analysis. The part was finally sent for final finishing to the net-shape design. Compared to obtaining the component from a forged block, RAMLAB saved 50% of material and with further improvements it is possible to reach 70% reduction.
Figure 3: Before milling
After milling half of the part
With this project RAMLAB showed the potential of the GMAW-WAAM system in printing Ti6Al4V metals parts. We are collaborating with several institutions to further research this topic. We made a small but important breakthrough in the GMAW-WAAM of Ti6Al4V parts, getting a step closer for our customers to print Ti6Al4V parts.
Special thanks to our partners: Hittech, AirProducts, Valk Welding, Autodesk, Cavitar, Element, TWI, Voestalpine Böhler Welding and the AMable initiative.
If you are interested to learn more about Wire Arc Additive Manufacturing of titanium parts, get in contact.
Figure 4: MaxQ, the Monitoring and Control system developed by RAMLAB