TP6: High-speed blanking with electromagnetically accelerated tools for the production of functional surfaces at very high strain rates

该公式考虑了相关工艺参数对高速冲裁中产生的绝热剪切带(ASB)及其在较大速度范围内性能的影响。在TP6中，Fraunhofer IWU研究了最高的冲裁速度(≥10 m/S)和应变速率(高达10⁵S⁻？)。这将允许在毛坯表面产生非常窄的ASB，并在具有良好导热性能的材料中启动ASB，将其用于生产技术，并首次从材料科学的角度对其进行表征。为了进行调查，IWU将开发和验证具有灵活应用的电磁加速冲头和广泛测量系统的测试台。设计了将冲击器加速到10~25m/S的电磁传动装置，并对成形所用材料进行了全面的工艺分析。将表征各种参数对冲裁过程和所产生的冲裁表面性能的影响。为了利用互补的实验和数值方法加深对相互作用的理解，将影响因素(例如撞击质量、速度)小心地彼此分开。在分析中，将整个过程分为电磁和机械两个子系统。电磁子系统包括电容通过电感系统的放电、磁场和洛伦兹力的建立。机械子系统描述了冲击器和冲头的动力学、机械应力、工件的弹塑性变形以及最终的断裂。冲击器是连接这两个子系统的纽带。在电磁子系统的分析中，识别和量化了相关参数(如电感变量、电容充电电压)对洛伦兹力和由此产生的冲击器运动的影响。在机械子系统的分析中，研究了刀具和零件的基本参数(如间隙、板厚)对零件断裂前的应力状态和变形的影响。在此基础上，研究了冲击器运动和应力状态对冲裁结果的影响。伴随整个研究项目的是一个数字支持的能源核算，作为技术调查的补充。

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.