Process-independent force and surface model for oblique cutting of fiber reinforced polymers

纤维增强聚合物通常用于轻量化设计。由于正交各向异性材料的性质，在切屑去除过程中的切削机制显着不同于各向同性材料。到目前为止，基本机制已主要研究正交切削。然而，斜切通常存在于工业实践中，其中由于工具的切削刃的空间接合条件而发生三维切削过程。空间啮合条件是由切削刃的三维空间取向和相对于纤维的切削方向的组合引起的，初步研究揭示了三维空间刀具-纤维取向对切削力和所得切削表面的显著影响。表面完整性会影响轻质结构在静、动载荷作用下的力学行为。特别地，发生纤维拔出对于表面完整性至关重要。该项目的目标是一个切削力和表面模型的加工纤维增强聚合物，特别考虑斜角切削。切削力的预测是基于一个半经验模型，它具有独立的过程的有效性。该模型将被转移到铣削。此外，预计在第二个项目阶段将转向钻孔和埋头孔。创新的实验装置首次实现了高效和全面的切削力系数识别，在高速切削以及刀具的任意方向和相对于纤维的切削方向下也是如此。表面模型是从空间负载情况和测量的表面条件之间的相关性。它可以预测与表面质量有关的关键切削条件，特别是纤维拔出。过程力和切削表面的旋转角度相关模拟允许在3D空间接合条件方面得出关于过程特定机制的结论，这到目前为止还不可能，因为重点是正交切削。与在钻削或铣削过程中通过校准进行的单纯机械力建模相比，半经验模型显示了载荷沿切削刃的沿着分布。这使得能够分析仅影响刀具小区域的现象，并显示出在表面质量方面的优化潜力。

Fiber reinforced polymers are often used in lightweight design. Due to the orthotropic material properties, the cutting mechanisms during chip removal differ significantly from those of isotropic materials. So far, the fundamental mechanisms have been investigated primarily for orthogonal cutting. However, oblique cutting is generally present in industrial practice, in which a three-dimensional cutting process occurs due to the spatial engagement conditions of the tool’s cutting edges. The spatial engagement conditions result from a combination of the 3D spatial orientation of the cutting edge and the cutting direction with respect to the fiber.Preliminary studies reveal a significant influence of the 3D spatial cutter-fiber-orientation on the cutting forces and the resulting cutting surface. The surface integrity can affect the mechanical behavior of lightweight structures under static and dynamic loads. In particular, occurring fiber pull-out is critical for the surface integrity. The objective of the project is a cutting force and surface model for the machining of fiber reinforced polymers with particular consideration of oblique cutting. The prediction of cutting forces is based on a semi-empirical model, which has a process-independent validity. The model will be transferred to milling. Furthermore a transfer to drilling out and countersinking is envisaged in a second project phase. Innovative experimental setups enable efficient and comprehensive identification of cutting force coefficients for the first time, also under high cutting speed as well as arbitrary orientation of the cutter and cutting direction relative to the fiber. The surface model is developed from the correlation between the spatial load situation and the measured surface condition. It allows the prediction of critical cutting conditions with respect to surface quality, in particular fiber pull-out. The rotation-angle-dependent simulation of the process forces and the cutting surfaces allows conclusions to be drawn about the process-specific mechanisms in terms of 3D spatial engagement conditions, which has not been possible up to now because of the focus on orthogonal cutting. Compared to the mere mechanistic force modelling by calibration in a drilling or milling process, the semi-empirical model shows the load distribution along the cutting edge. This enables the analysis of phenomena which are only affecting a small region of the cutter and shows optimization potential in terms of surface quality.