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

该项目的第三阶段侧重于对带有AISI 4140（德国等级42CrMo4）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。与项目的第二阶段相比，将通过交叉钻孔与组件上的进一步钻井相结合来增加复杂性。通过这个例子，可以更好地描述钻井过程中热效应和机械效应的相互作用。为了实现这一目标，将上一阶段钻井作业的简化3d模型调整到变化的起始位置，并在开始时进行实验验证。对于此转移步骤，可以使用模块化模型构造来定制每个部分模型以适应其特定的应用程序。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。借助于先进的仿真模型，将对残余应力和变形状态形成的总体热平衡进行参数化研究。通过这种方式，可以获得有针对性地产生残余应力和由此产生的畸变的必要信息。工件关于钻孔距离的参数化将完成这个工作包。在热平衡可以被充分描述之后，对冷源使用的研究将遵循旨在通过控制简化部件的冷却来最大限度地减少变形的可能性。这种冷源是用来运行后的制造工艺，还可以平行生产进一步的钻孔。根据模型的计算结果，将得到激活冷源的最佳时间、地点和强度。在随后的开发步骤中，将开发圆铣削模型作为补偿残余应力和变形条件的进一步方法，并在简化的部件中再次进行测试。使用该模型，将根据圆度和方向检查钻孔几何形状，以便推导出由受控的非圆形和弯曲钻孔引起的变形行为的补偿策略。这允许产生孔洞和整体几何形状，这是达到热平衡后理想的。在最后一步，主动几何补偿将在协同使用所有获得的见解和结果以及圆铣和冷源对复杂部件的应用下进行。最后，将实验验证单一或多种补偿策略的效果。

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.