GOALI: Fundamental Investigation of Constrained Cutting for High Performance Machining of Difficult-to-Cut Materials

这个学术与工业联络奖（GOALI）的资助机会支持一种新的金属切削方法的基础研究，以提高加工难切削材料的效率。难以切削的材料在需要更高切削力的典型加工条件下具有差的可加工性，并且导致更高的温度、更短的刀具寿命和差的表面光洁度。这些切削困难从根本上归因于难切削材料的难切屑形成特性和常规切削控制切屑形成能力的缺乏。新的切削方法除了使用切削刀具外还使用约束刀具，以在切削过程中直接控制切屑的形成。这使得切屑形成特性得以优化，从而以较低的切削力实现有效的材料去除，从而延长刀具寿命，改善表面完整性，并提高材料去除率。这种受限切割方法使美国制造业受益匪浅，例如汽车、航空航天和能源，这些行业大量使用难以切割的材料。与美国刀具行业的合作伙伴密切合作，确保技术转让，以开发下一代刀具和加工策略。该项目通过研究生和本科生，特别是女性和代表性不足的少数民族学生参与研究和教育，为先进制造和工程培养训练有素的劳动力。该项目的研究重点是调查几何约束剪切变形区如何影响机械加工过程的力学，动力学和生成的表面完整性。传统的金属切削工艺缺乏对切屑形成的直接控制。通过附加约束工具控制剪切变形区可以减少切削工作量，显著改善表面完整性和加工稳定性。约束切削过程中的切屑变形进行了实验分析，通过原位数字成像和分析和计算建模，以了解约束参数（位置和几何形状）和切削力（力，能量和温度）之间的基本关系。约束剪切变形区减少了塑性变形和热机械载荷。这改善了表面光洁度，增强了微观结构，并降低了残余应力。实验表征以及与变形和温度分析的相关性产生了新的知识，从而能够更好地控制生成表面的完整性。约束工具的过程和加工设备的耦合动力学的影响也进行了研究，这导致新的设计约束工具的几何形状，以控制和抑制高频自激颤振不稳定性加工过程中。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research on a novel metal cutting method for enhancing the efficiency of machining difficult-to-cut materials. Difficult-to-cut materials have poor machinability in typical machining conditions requiring higher cutting forces, and resulting in higher temperatures, shorter tool life, and poor surface finish. These cutting difficulties are fundamentally attributed to the difficult chip formation characteristics of difficult-to-cut materials and the lack of conventional cutting’s ability to control chip formation. The new cutting method uses a constraining tool in addition to a cutting tool to enable direct control of chip formation during the cutting process. This allows the chip formation characteristics to be optimized, which leads to efficient material removal with lower cutting forces, resulting in longer tool-life, improved surface integrity, and higher material removal rates. The constrained cutting method significantly benefits U.S. manufacturing industries, such as automotive, aerospace and energy, where difficult-to-cut materials are heavily used. Close collaboration with a partner from the U.S. cutting tool industry ensures technology transfer to develop next generation cutting tools and machining strategies. The project generates a well-trained workforce for advanced manufacturing and engineering through the involvement of graduate and under-graduate students, particularly, women and under-represented minorities, in research and education.The research focus of this project is to investigate how geometrically constraining the shear deformation zone affects the mechanics, dynamics, and generated surface integrity of machining processes. Conventional metal cutting processes lack direct control of chip formation. Controlling the shear deformation zone by an additional constraining tool can lead to reduced cutting effort, dramatically improved surface integrity and machining stability. Chip deformation during constrained cutting is analyzed experimentally through in-situ digital imaging and by analytical and computational modelling to understand the fundamental relationship between constraining parameters (location and geometry) and cutting effort (force, energy, and temperature). Constraining the shear deformation zone reduces plastic deformation and thermomechanical loads. This improves surface finish, enhances microstructure, and reduces residual stress. Experimental characterization and correlation with deformation and temperature analysis generate the new knowledge to enable better control of the integrity of the generated surfaces. The effect of constraining tool on the coupled dynamics of the process and the machining equipment is also investigated, which leads to new designs of constraining tool geometries to control and suppress high-frequency self-excited chatter instabilities during machining. This allows machining of precision parts at significantly higher depth, feed and speed leading to greater material removal rates and superior surface finish.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.