Efficient Numerical Methods for Tool Optimization in Cold Forging

制造技术中的轻量化设计和资源效率要求使用高强度材料和复杂的几何形状，以便在减轻重量的同时实现同等的部件功能。这对成形工具提出了很大的挑战，并使其在工具耐用性和零件精度方面的设计复杂化。因此，使用数值方法进行刀具设计是必不可少的。在这种情况下，通常的方法是计算孤立的几何元素对刀具载荷和零件几何的影响，然后通过迭代过程进行手动刀具优化。虽然这一过程可以改善单个方面，但不能基于该策略实现全局刀具优化，通常可以通过数学算法计算全局最优解。然而，它们在成形工具优化中的应用有两个弱点。首先，现在刀具载荷的计算几乎完全是通过有限元方法来完成的。这种方法需要很高的计算工作量来进行刀具/工件-交互作用的整体计算。由于迭代步骤很多，这使得优化过程效率低下。其次，由于计算时间有限，常常忽略机床刚度对刀具载荷的影响。因此，优化过程的输入信息已经包含了很大的不准确性，为了克服这些不足，在应用项目的背景下，将开发一种新的高效仿真工具和基于过程中实际刀具负载的整体、系统的工具优化方法。从而实现本项目的目标，即通过智能化、数值化、迭代的工具设计，显著提高冷锻工具的耐用性和零件的精度。实质上的创新之处在于开发了有效的耦合方法，用于通过弹性建模计算刀具载荷，同时考虑到工艺/机器-交互作用，以及对弹性刀具应变造成的部件偏差进行数字补偿。通过将新开发的计算方法集成到自动化刀具优化方法中，即使迭代步骤很多，也可以实现优化刀具几何形状的省时计算。为了实现这一目标并开发出建设性的跨学科方法，来自制造工程、数值和应用数学的科学家将在整个研究期间密切合作。

Lightweight design and resource efficiency in manufacturing technology require the use of high-strength materials and complex geometries in order to achieve equivalent part functionality, while reducing its weight. This poses a big challenge for forming tools and complicates their design with regard to tool durability and part precision. Therefore the use of numerical methods for tool design is essential. In this context the usual approach is to calculate the influence of isolated geometric elements on tool loads and part geometry and afterwards perform a manual tool optimization by means of an iterative process. While this procedure may improve single aspects, one cannot achieve a global tool optimization based on this strategy.In general a global optimum can be computed by means of mathematical algorithms. Nevertheless, their use for the optimization of forming tools features two weak points. Firstly, nowadays the computation of tool loads is almost exclusively performed by means of the Finite Element Method (FEM). This method requires high computational effort for a holistic computation of tool/ workpiece-interactions. Due to the large number of iteration steps this renders the optimization process inefficient. Secondly, due to limited computing time one often omits the influence of machine stiffness on tool loads. Therefore, the input information for the optimization process already contains significant inaccuracies.In order to remove these shortcomings, in the context of the applied project new efficient simulation tools and a holistic, systematic approach for tool optimization, based on the actual tool loads during process, will be developed. Thereby the goal of this project, namely a significant increase in durability of cold forging tools and in the precision of the parts by means of intelligent, numerical, iterative tool design, will be achieved. The substantial novelty is the development of efficient coupled methods for the computation of tool loads by means of elastic modeling, while accounting for process/machine-interactions, as well as the numerical compensation of component deviations caused by elastic tool strains. By integration of the newly developed computing methods into a methodology for automated tool optimization, a time-efficient computation of the optimized tool geometry can be realized despite the large number of iteration steps. In order to reach this goal and to develop constructive interdisciplinary approaches scientists from manufacturing engineering, numerics and applied mathematics will closely work together for the whole research period.