Analysis of the heat input into the workpiece due to drilling and the resulting influences on the wall of the hole for 42CrMo4

该项目第三阶段的重点是对具有AISI 4140(德国42CrMo4级)钻孔的复杂部件的热变形进行主动几何补偿。这一目标将通过基于仿真的加工策略设计来实现。与项目第二阶段相比，将通过交叉钻孔和对部件进行进一步钻探来增加复杂性。为了达到这一目的，在最后一段时间内实现的钻井操作的简化3D模型将被调整到改变的起始位置，并在开始时进行实验验证。对于该转移步骤，可以使用模块化模型构造来根据其特定应用来定制每个部分模型。作为这项工作的一部分，在钻头热输入模型中实现的温度项将同时扩展，以实现钻头几何形状的通用设计。借助于先进的模拟模型，将通过参数研究来研究导致残余应力和变形状态形成的整体热平衡。通过这种方式，可以获得目标残余应力的产生和由此产生的变形的基本信息。相对于打孔距离的零件的参数化将完成该工作包。在完全描述热平衡之后，接下来将研究冷源的使用，目的是通过对简化部件的受控冷却来最小化变形潜力。这种冷源是用来生产后运行的制造工艺，还可以在生产的同时进一步打孔。通过模式的计算，得到了冷源激活的最佳时间、地点和强度。在随后的开发步骤中，将开发圆形铣削模型，作为补偿残余应力和变形条件的另一种方法，并在简化部件中再次进行测试。利用该模型，将根据圆度和定向来检查钻井几何形状，以便针对受控的非圆形和弯曲钻孔所导致的变形行为得出补偿策略。这允许产生孔洞和整体几何形状，这是达到热平衡后的理想状态。在最后一步中，将综合运用所有已有的见解和成果，并针对复杂零件应用圆磨和冷源，进行主动几何补偿。最后，对单一或多个补偿策略的效果进行了实验验证。

The third phase of the project focusses on an active geometric compensation of thermal deformations for a complex component with drilling holes for AISI 4140 (German Grade 42CrMo4). This goal will be achieved by a simulation-based design of machining strategies. An increase of complexity compared to the second phase of the project will be achieved by intersecting drilling holes in combination with further drillings on the component. With this example, the interactions of thermally and thereby mechanically induced effects can be represented much better during the drilling operation.To reach this objective, the simplified 3D-Model of a drilling operation achieved during the last period will be adjusted to the changed starting position and validated experimentally at the beginning. For this transfer step the modular model construction can be used to tailor each partial model to its specific application. As part of this work, the temperature terms implemented in the model for the heat input of the drill will be extended simultaneously for a universal design of the drill geometry. With the help of the advanced simulation model the overall heat balance which is responsible for the formation of residual stress and distortion states will be investigated by parametric studies. In this way essential information for the targeted generation of resiudal stresses and the resulting distortions can be obtained. A parametrization of the workpiece with respect to the distance of drilling holes will complete this workpackage. After the heat balance can be fully described, the investigation of the use of cold sources will follow aiming to minimize the distortion potential by controlled cooling of a simplified component. This cold sources are to be used to run after the manufacturing process, but also parallel to the production of further drilling holes. As a result of the calculations in the model the best times, places and intensities for the activation of the cold sources will be obtained. In a subsequent development step a circular milling model will be developed as a further method for compensating the residual stress and distortion conditions and tested again in the simplified component. With this model, drilling geometries will be examined in terms of roundness and orientation in order to derive compensation strategies for the distortion behavior resulting from controlled non-circular and curved drilling of the holes. This allows to produce holes and overall geometries, which are ideal after reaching the thermal equilibrium. In the final step, the active geometric compensation will be carried out under synergetic use of all gained insights and results and application of circular milling and cold sources for the complex component. At the end the effects of single or multiple compensation strageties will be vaildated experimentally.