Coupling of analytical and numerical models to simulate the thermomechanical interactions during the milling of complex workpieces

在复杂薄壁工件结构的铣削加工过程中，会产生变形。这些偏转是由机械和热过程影响引起的，可能会严重影响加工结果。因此，优先程序的主要目标是在三个项目阶段中对热引起的变形进行建模、仿真和最终补偿。在项目的前两个阶段，进行了变形的建模和模拟。在第三阶段，应采用适当的方法来减少热致变形。测量表明，通过工艺参数的变化，工件变形的减少具有很高的潜力。因此，应该采取两阶段的方法，一方面区分过程方面的方法，另一方面区分补偿策略。工艺侧方法通过修改工艺参数（切削速度v_c，每齿进给量f_z）或通过改变切削深度（a_p）和宽度（a_e）之间的比率来追求加工策略的改变。然而，补偿策略通过通过倾斜工具提供工件的变形来损害路径规划，或者通过附加的致动器抵消机械或热变形。与补偿策略相反，前面提到的两种减少方法与高技术努力有关，只有在工艺方面的策略不足以维持所需的公差时才使用。在项目的前两个阶段中开发和验证的过程模型构建了两种减少方法的基础。该模型能够模拟由任何可加工几何形状的铣削过程引起的变形，从而可以推导出在变形发生之前避免变形的减少方法。

During the milling process of complex thin-walled workpiece structures, deformations occur. These deflections are caused by mechanical and thermal process influences and may substantially affect the machining results. Therefore, the main objective of the priority program is the modeling, the simulation and ultimately the compensation of the thermally caused deformations in the course of three project phases.During the first two phases of the project the modeling and the simulation of the deformation was treated. Within the third proposed phase, appropriate methods should be used to reduce thermally induced deformations. Measurements demonstrate a high potential for the reduction of workpiece deformations through a variation of process parameters. Therefore, a two-staged approach should be pursued, which differentiate between process sided methods on the one hand and compensation strategies on the other hand. The process sided approach pursues a change of the machining strategy by a modification of the process parameters (cutting speed v_c, feed per tooth f_z) or by changing the ratio between cutting depths (a_p) and widths (a_e). However, the compensation strategies either impair the path planning by providing the deformation of the workpiece by means of tilting the tool or counteract the deformations mechanically or thermally with additional actuators. Contrary to the compensation strategy the first two mentioned reduction methods are associated with a high technical effort and are only used, if process sided strategies are insufficient to maintain required tolerances. A process model, which was developed and validated within the first two phases of the project, builds the basis of both reduction methods. This model is able to simulate the deformations caused by the milling process of any machinable geometry so that reduction methods to avoid deformations before they are occurring can be derivated.