The Fraunhofer Institute for Laser Technology ILT is tackling the issue of 3D-printing large components economically by using a new process called Hybrid AM.
An important step forward in Hybrid AM process development is a new wire LMD head and its modular components, which the Aachen-based experts will be presenting for the first time at Formnext, to be held in Frankfurt from 19 to 22 November 2019. The joint Fraunhofer presentation will be on show in Hall 11, Booth D51
Production experts are increasingly facing a dilemma: Conventional manufacturing processes such as turning, milling, eroding or forming are gradually reaching their limits when large and complex individual metal components need to be manufactured. While additive manufacturing processes offer significant advantages in terms of saving raw materials, they still only have low deposition rates. Here, it makes sense to combine conventional and additive manufacturing processes, the researchers explain.
As part of the collaborative Pro LMD project, which is being funded by the German Federal Ministry of Education and Research (BMBF), Fraunhofer ILT is working with industrial partners to develop new processes for integrating hybrid laser material deposition (LMD) processes into the production chain. Their aim is to develop processes and systems that can be used, for example, to apply reinforcements or other geometric features onto cast or forged blank parts via LMD.
Integrating hybrid production technology into existing systems
Developed at Fraunhofer ILT and now implemented in the Pro LMD project, the new processing optics — with a ring-shaped beam — play an important role in coaxial LMD with wire. “The main advantage of the optics is the directional independence. Combined with the low-cost filler material wire and nearly 100 % utilisation, the overall costs can be reduced drastically,” explains Max Fabian Steiner, a researcher partaking in the project at Fraunhofer ILT.
“In addition, the process is dust-free. Compared to powder-based processes, it not only offers cost savings but also improves occupational safety as well as environmental and employee protection,” Steiner continues.
Working in high quality regardless of direction
The main features of the new processing optics are its directional independence and uniform intensity distribution of the laser beam intensity over the ring. Since reflective optics are being used, such as copper in this case, high powers in a wide wavelength range are possible. Wire LMD can be used to manufacture components in very high quality without pores and with extremely low post-processing requirements. In addition, the new head enables welding on 3D surfaces. As with most LMD processes, the new optics are equally suitable for repairing components.
By combining the non-directional process with a six-axis robot, the project partners have made the machining process very flexible. Since the application process can be controlled accurately, the process is stable even with large components and at high deposition rates, while maintaining consistent quality, according to the researchers.
Inert gas cell enables titanium 3D printing
The new optics will be integrated into a process chain that improves the quality of the other components thanks to intermittent scanning. For this purpose, the geometry of the component is continuously recorded in order to adapt or correct the path planning with the aid of this data. An inert gas cell also allows users to repair titanium components in an argon atmosphere or to produce fully additive titanium components using 3D printing, the researchers explain.
The experts from Fraunhofer ILT will be presenting the modular laser wire deposition head, the entire LMD process chain and the hybrid process at Formnext, taking place in Frankfurt from 19 to 22 November.