Project Details
Projekt
TP6: High-speed blanking with electromagnetically accelerated tools for the production of functional surfaces at very high strain rates
Applicants
Dr.-Ing. Verena Psyk; Dr.-Ing. Sven Winter
Subject Area
Mechanical Properties of Metallic Materials and their Microstructural Origins
Joining and Separation Technology
Joining and Separation Technology
Term
since 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 460484491
The FOR considers the influences of relevant process parameters on the resulting adiabatic shear bands (ASB) and their properties over a wide range of speeds in high-speed blanking. In TP6, Fraunhofer IWU investigates the highest blanking speeds (≥10 m/s) and strain rates (up to 10⁵ s⁻¹). This shall allow to generate very narrow ASB in the blanked surfaces and to initiate ASB in materials with good thermal conductivity, exploit them for production technology and characterize them in terms of materials science for the first time. For the investigations, IWU will develop and validate a test rig with a flexibly applicable electromagnetically accelerated punch and extensive measurement systems. The electromagnetic drive is designed to accelerate an impactor to maximum speeds of 10–25 m/s. Then a comprehensive process analysis is performed for the materials used in the FOR. The influence of various parameters on the blanking process and the resulting blanked surface properties will be characterized. In order to create a deep understanding of the interactions using complementary experimental and numerical approaches, the influencing factors (e.g. impact mass, speed) are carefully separated from one another. In the analysis, the overall process is divided into an electromagnetic and a mechanical subsystem. The electromagnetic subsystem includes the capacitor discharge via the inductor system and the buildup of magnetic field and Lorentz force. The mechanical subsystem describes the dynamics of the impactor and punch, the mechanical stresses, the elasto-plastic deformation of the workpiece and finally the fracture. The impactor is the connection between the two subsystems. During the analysis of the electromagnetic subsystem, the influences of relevant parameters (e.g. inductor variants, capacitor charging voltage) on the Lorentz forces and the resulting impactor motion are identified and quantified. In the analysis of the mechanical subsystem, the influence of essential tool and workpiece parameters (e.g. clearance, sheet thickness) on the stress state and the deformation of the workpiece up to fracture is investigated. Based on this, the influence of impactor motion and stress state on the blanking result is investigated. The technological investigations are supplemented by a numerically supported energy accounting that accompanies the entire research project.
DFG Programme
Research Units
