Two-Dimensional Cutting of Polycrystalline Diamond and CBN Tools and Dies using a Novel Laser/Waterjet Hybrid Manufacturing Process

本项目的目的是验证下列两个假设：1)激光和水射流的联合作用将导致在二维切割过程中产生垂直于切割路径的拉应力和裂纹扩展；2)如果材料的去除机制从热熔化和蒸发(激光切割)或材料侵蚀(电火花加工)转变为通过裂纹扩展实现材料分离，则可以得到更小的开槽；2)在加工多晶钻石和多晶立方氮化硼的二维轮廓时，可以比传统的加工方法获得更高的切割速度和显著的节能效果。该项目的方法是检验假设，依靠基本的断裂力学模型和实验来研究超硬材料由于激光加热和水射流淬火的热和化学效应而产生的受控断裂。研究活动的成功完成将导致一种新的脆性材料加工方法，并详细了解这一新工艺背后的基本基础。这种新型的混合制造工艺将有可能分别为金属切割和拉丝行业提供高性能的刀具和模具。汽车、木工和其他使用合成钻石工具的行业将从这项研究中受益匪浅。教育和外联成果将包括对研究生进行先进制造研究方面的培训，将研究成果吸收到新的课程单元中，让来自代表性不足群体的本科生参与研究小组，并通过期刊出版物、会议、行业访问和讲习班传播研究成果。

The objective of this project is to test the following two hypotheses: 1) the combined action of laser and waterjet will result in development of tensile stresses perpendicular to cutting path and propagation of cracks along cutting path during the two-dimensional cutting and 2) if the material removal mechanism were changed from thermal melt and evaporation (laser cutting) or material erosion (electrical discharge machining) to material separation through crack propagation, then smaller kerf; parallel walls; higher cutting speed and substantial energy savings can be attained in the machining of two-dimensional profiles of polycrystalline diamonds and polycrystalline cubic boron nitride over conventional machining processes. The project's approach is to test the hypotheses relies on fundamental fracture mechanics modeling and experiments to investigate controlled fracture of superhard materials due to thermal and chemical effects of laser heating and waterjet quenching.Successful completion of the research activities will lead to a novel machining method for brittle materials along with a detailed understanding of the fundamental underpinnings behind this new process. This novel hybrid manufacturing process will have potential to offer high performance tools and dies for metal cutting and wire drawing industries respectively. Automotive, woodworking and other industries that use synthetic diamond tools would greatly benefit from this research. Education and outreach outcome will include training of graduate students in advanced manufacturing research, assimilation of the research outcomes into new course modules, the involvement of undergraduates from underrepresented groups in the research team and the dissemination of the research results through journal publications, conferences and industry visits and workshops.