ABSTRACT

Drilling of high-strength carbon/epoxy composites has been a critical procedure in the industry due to the need to create holes for mechanical assemblies. However, the inherent anisotropy and heterogeneity of the fibrous composites complicate the material removal process and induce tremendous challenges for the manufacturing sectors. The present paper addresses the machining issues of T700 carbon fibers reinforced epoxy laminates by using the diamond-coated brad spur drills. The cutting tools are featured by three protruding edge tips devoted to the minimization of drilling thrust forces for the composite laminates. The machining experiments were conducted under varying process conditions to investigate the parametric impacts on the machining responses. The cutting-induced delamination was studied using a novel quantification method. The work novelty is focused on revealing the machining characteristics of high-strength fibrous composites and evaluating the functionality of the specialized tools for the composite drilling. The process parameters greatly affect the drilling forces/temperatures and delamination factors. Delamination is shown to occur inside the inner plies of the composite and propagate rapidly toward the hole exit side. Moreover, surface cavities and fiber fractures dominate the failure of cut composite hole walls.

摘要

由于需要在机械组件上打孔，因此高强度碳/环氧树脂复合材料的钻孔已成为行业中的关键程序。但是，纤维复合材料固有的各向异性和异质性使材料去除过程复杂化，并给制造行业带来巨大挑战。本文通过使用金刚石涂层的布拉德直齿钻头解决了T700碳纤维增强环氧层压板的机加工问题。切削工具的特征在于三个突出的边缘尖端，这些尖端专门用于最大程度地降低复合材料层压板的钻孔推力。在不同的工艺条件下进行了机加工实验，以研究参数对机加工响应的影响。使用一种新型的定量方法研究了切削引起的分层。这项工作的新颖性集中在揭示高强度纤维复合材料的加工特性以及评估复合材料钻削专用工具的功能上。工艺参数极大地影响钻孔力/温度和分层因子。已显示分层发生在复合材料的内层内部，并迅速向孔出口侧传播。此外，表面空洞和纤维断裂主导了复合材料切割孔壁的破坏。已显示分层发生在复合材料的内层内部，并迅速向孔出口侧传播。此外，表面空洞和纤维断裂主导了复合材料切割孔壁的破坏。已显示分层发生在复合材料的内层内部，并迅速向孔出口侧传播。此外，表面空洞和纤维断裂主导了复合材料切割孔壁的破坏。