Property-control in forging on screw presses by energy dosage and local actuators

通过能量剂量和局部执行器对螺旋压力机锻造进行性能控制

• 批准号: 424334584
• 负责人: Professor Dr.-Ing. Markus Bambach
• 金额: --
• 依托单位: Departement Maschinenbau und Verfahrenstechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424334584?language=en
• 关键词: Property; control; forging; screw; presses

Closed-die forging usually has the goal of shaping a workpiece at reduced forming forces and utilizing the microstructural changes occurring at high homologous temperatures to set the properties for the application. The evolution of the microstructure can be considered as a dynamic system during hot forming. It is controlled by the temporal evolution of the temperature and velocity fields at the material points in the workpiece. Variations in the initial microstructure and the friction and heat transfer conditions lead to variations in properties. When forging on screw presses, the workpiece is brought into shape with several blows. Here it generally seems possible to control the dynamic system of microstructure evolution over the course of the blows. Adaption of impact energy and interpass times between impacts could be used to compensate for deviations, e.g., with respect to temperature, due to a delayed transport of the workpiece. Usually, it is not possible to specifically influence critical workpiece areas during drop forging. There is a lack of degrees of freedom in the tools, so that forming energy cannot be locally introduced in a targeted manner. So far, no work is known which uses the impact energy specifically as a control variable to directly control the microstructure and property formation during forging. Also, no local impact on critical locations is possible because actuators in forging tools that go beyond the knock-off function are currently not state-of-the-art. The subject of this project proposal is the research, implementation and validation of observer and closed-loop control strategies for the global and local property control of energy-bonded forging on screw presses. If the target microstructure is specified in a specific area in the workpiece, an optimal impact sequence can be calculated as a reference using static optimization methods. The development of the microstructure is then estimated from measured sensor values during the course of the process. A first sub-goal is the development of an energy-based material model, i.e. the formulation and validation of material equations for the property-determining microstructural variables on the basis of the energy introduced into the microstructure by forming. The material model shall be combined with an online process model based on interpolated FEM solutions. Here, an equation of motion for the boundary of the domain with fulfilled microstructural requirement is to be derived. This model forms the basis for the control, which is to be implemented as a follow-up control between the actual state and the target state of the domain boundary. The developed solution is first tested virtually using an FEM model and then transferred to the screw press of the chair of mechanical design and manufacturing.

闭式模锻的目标通常是在降低成形力的情况下成形零件，并利用在高相应温度下发生的组织变化来设定应用的性能。热成形过程中微观组织的演变可以看作是一个动态系统。它受控于工件内材料点温度场和速度场的时间演化。初始微结构以及摩擦和热传递条件的变化会导致性能的变化。当在螺旋压力机上锻造时，用几次打击就能使工件成形。在这里，一般情况下，似乎可以控制打击过程中微观组织演变的动态系统。冲击能量和冲击之间的通道间时间的适应可以用来补偿由于工件的延迟运输而引起的偏差，例如相对于温度的偏差。通常，在模锻过程中不可能具体影响关键的工件区域。工具中缺乏自由度，因此不能以有针对性的方式在局部引入成形能量。到目前为止，还没有专门将冲击能作为控制变量来直接控制锻造过程中组织和性能形成的工作。此外，不可能对关键位置产生局部影响，因为超出仿制功能的锻造工具中的致动器目前还不是最先进的。本项目提案的主题是研究、实现和验证螺旋压力机上能量键合锻造的全局和局部性能控制的观测器和闭环控制策略。如果在工件的特定区域中指定了目标微观组织，则可以使用静态优化方法来计算最优冲击顺序作为参考。然后，根据在该过程中测量的传感器值来估计微结构的发展。第一个子目标是开发基于能量的材料模型，即根据通过成形引入到微观结构中的能量来制定和验证决定性能的微观结构变量的材料方程。材料模型应与基于内插有限元解的在线工艺模型相结合。在此，推导出满足微结构要求的区域边界的运动方程。这一模型构成了控制的基础，该控制将作为域边界的实际状态和目标状态之间的后续控制来实施。开发的解决方案首先使用有限元模型进行虚拟测试，然后转移到机械设计和制造部门的螺旋压力机上。