One of the most innovative technologies at ZAL is Laser Shock Peening (LSP), a process that on the one hand increases the durability of aircraft parts and on the other hand can form sheet metal parts. In this process, short high-energy laser pulses strike a component, where they cause a plasma explosion. This explosion creates immense short-term pressure on the surface of the workpiece, generating compressive residual stresses near the surface. These residual compressive stresses introduced by laser pulses can make components more fatigue-resistant and thus increase durability, but they can also reshape parts.
With the Laser Shock Peening facility (max. 10 joules of pulse energy), ZAL has a laser peening cell large enough to treat industrial parts up to 180 kg and 5 m long. ZAL experts there are currently working on two LuFo 6-1 projects – PEENCOR and LEADPEEN.
PEENCOR – First aid in case of spring back
In the PEENCOR project, the aim is to correct deformations in the component using LSP – explicitly for formed titanium sheets. Such undesirable deformations are caused, for example, by spring back effects during bending. Therefore, it is generally a great challenge in forming technology to counteract these deformations. Engineers are often involved in compensating for spring back and correcting distortions at considerable expense. With PEENCOR, the ZAL LSP team, together with its partners FormTech GmbH, Helmholtz-Zentrum Hereon, and Leuphana University, aims to straighten components intelligently. To do this, the experts at ZAL GmbH scan the deformed component with a metrology system (3D scanning system), compare the scan result with the target geometry from an existing CAD file, and thus obtain the deviations. An intelligent algorithm determines a laser peening pattern, which is passed on to the LSP system. The system then knows where to place these laser pulses to achieve the desired shape.
LEADPEEN – fast spare parts
LEADPEEN also processes aircraft components with laser shock peening. The focus is on components on the secondary aircraft structure that have been damaged during the flight. The ZAL team and its research partner Lufthansa Technik are working on the project to provide replacement components using laser peening. The aim is to optimize the performance of processes that are currently manual.
As with PEENCOR, the target properties of the components are available digitally as a CAD model. A self-developed AI tool, through the analysis of which the correct laser peening parameters are determined, is the subject of research. The LSP system finally converts the peening to the target properties. The research focus of the ZAL engineers is primarily on AI, i.e. the tool based on artificial intelligence, which analyzes the target and actual properties and calculates the correct parameters from them.
ZAL team maps the entire process chain
Thanks to digital tools, the ZAL team maps the complete process chain with LSP. This means that it enables a fully automated forming process at ZAL. For example, if the ZAL experts want to form a sheet metal component with complex curved geometry, they can design it in the CAD program. A CAM program then automatically generates the robot paths along which the robot guides the component past the laser pulses. The engineers then clamp the component in the system and press start. The following process in the LSP system runs completely independently. The result is a fully formed workpiece. The LSP system is therefore an important unique selling point. It has two robots that can move the component in various degrees of freedom. In addition, ZAL GmbH has the corresponding know-how with automation, programming, and the appropriate expertise in terms of forming and materials.
What’s next for LSP?
The ZAL team is working on the further development of the LSP process to optimize it. In particular, the focus is on making the process more sustainable. In addition, the constant goal is to expand the use cases. Ultimately, the aim is also to build bridges to other research disciplines, e.g. by reworking additively manufactured, i.e. 3D-printed, components using LSP. One can be curious.
Do you find Laser Shock Peening exciting and would like to learn more? Give us a call, we are looking forward to it!
Contact Laser Shock Peening:
Dr.-Ing. Frieder Zimmermann
Senior Development Engineer Advanced Materials
+49 40 248 595 121
+49 173 76 28 728
PEENCOR and LEADPEEN are funded by the Federal Ministry for Economic Affairs and Climate Action based on a resolution of the German Bundestag within the 6th Aviation Research Program (1st call). We expressly thank you for the financial support.
