As a shear cutting process, fine blanking is an important technology in sheet metal working. In many industries - from the automotive sector to the electrical and precision engineering industries to medical technology - the cutting process is used when it comes to producing ready-to-install components with outstanding dimensional accuracy and surface quality.
As material weight plays an important role in lightweight construction, fine blanking is mainly used for thin, high-strength steels. However, the process is increasingly reaching its limits because fine blanking of higher-strength steels results in increased edge rollover. To achieve the required squareness of the cut surface and avoid edge rollover on the component, thicker sheets are fine blanked and the sheet surface is reworked by milling and grinding processes. With a thermally assisted fine blanking process, which is being developed in the project, these finishing operations can be dispensed with because the flow stress and thus the reduced edge rollover are prevented.
In the research project "FESt", the Fraunhofer IPT and its project partners from industry and science are developing a thermally assisted fine blanking process for machining high-strength sheet metal.
The local heating of the material changes the material properties at the shear point for the better: Not only the shear force is reduced by up to 80 percent, but up to 24 percent of the material can also be saved, since no further machining steps are required.
The aim of the project is to significantly reduce the resource requirements and CO2 emissions generated along the process chain compared with the conventional fine blanking process. The research focus of the project is therefore on process, system and tool development for integrated local heating. Various heating technologies are being used and investigated for this purpose.
The Fraunhofer IPT analyzes and evaluates the process design for different heating methods. Laser and induction heating are particularly well suited for local thermal softening at the fine blanking edge. Two of the development goals are the integration of the hy-PRESS module for local heating of the material in front of the tool and the process development for targeted heat input (tailored heat) including the coordinated lubricant concept for high temperatures.
For this purpose, the research team investigates the material behavior in experimental tests. The process simulation is calibrated and validated with real test data. Industrial testing of the overall process chain is the responsibility of an interdisciplinary research consortium. The aim is to improve the efficiency of the process through local heating and to avoid post-processing steps. In this way, resource savings can be achieved, which offer corresponding lightweight construction and CO2 reduction potential.
Machine Tool Laboratory WZL of RWTH Aachen University
Funding code: 03LB3016B
|2023||Design of freeform optic module creating a ring-shaped laser beam profile for localized heating of sheet metals
Chen, Teng; Schmid, Tobias; Hüsing, Florian; Janssen, Henning; Brecher, Christian