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Video: Avoid Cracks In 3D Printed Metal Parts
2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-06-01 01:49
With selective laser melting (SLM), a powerful laser melts and melts metal powder together and gradually forms a 3D component layer by layer. At the end of the process, the remaining powder is removed. But some metals and alloys cannot withstand the high temperature fluctuations that SLM brings with them and cause them to break
Researchers at the Laboratory for Thermomechanical Metallurgy (LMTM) at the University of Lausanne École Polytechnique Fédérale de Lausanne (EPFL) under the direction of Roland Logé have developed a new process in which a second laser treatment is performed every few layers during the construction phase. This drastically reduces the formation of cracks and the metal parts become resistant to high temperatures, damage and corrosion.
The patented technology, which was published in the Additive Manufacturing magazine, could be used, for example, to manufacture new electricity-generating turbine blades or important aircraft components.
How does laser shock peening work?
Using so-called laser shock peening, or LSP for short, the researchers were able to “heal” cracks in no time during 3D printing. LSP works with the periodic alignment of high-intensity laser pulses on the component to be built. It acts like a kind of high-energy photonic "hammer" that sends shock waves through the material.
The process consists of two lasers. The first one melts the metallic powders and heats the molten material, while the second one creates stresses in the component at targeted points to remove cracks. “Laser shock blasting is usually reserved for surface treatments,” explains Logé. "But in our case, it has become a mass treatment by working in 3D in the material itself."
95% of the cracks are eliminated
The results speak for themselves. The researchers found that the technique eliminates up to 95% of the cracks normally seen in a nickel-based superalloy. You are now planning to apply the process to other crack-sensitive alloys.
Several 3D printing companies have expressed interest in the new technology. "This hybrid 3D printing process offers applications that go far beyond crack removal," adds Logé. "We are just beginning to understand its full potential."
