GOALI/Collaborative Research: Mechanics and Dynamics of Low Frequency Vibration Assisted Machining

该学术与工业联络资助机会（GOALI）项目与两所大学和工业界合作，进行关于应用缓慢振动增强加工过程中材料去除效果的基础研究。振动已被视为一种干扰和低效率的来源，许多制造操作，包括机械加工过程。然而，这种新方法试图使用低频（慢）振动来改善切削刀具和工件之间的接触条件，从而提高加工效率。通过将受控的缓慢振荡应用于切削刀具，这种新的切削工艺可以以较低的切削力和能量实现材料去除，获得较长的刀具寿命，并提高加工工艺的整体稳定性以实现较高的材料去除率。它可以显着提高制造业的生产力，从而提高美国的竞争力和繁荣，以及产品质量，特别是对于美国汽车，航空航天，国防和能源部门使用的难切割金属合金制成的部件。与美国汽车工业合作伙伴的合作将有助于确保技术转移和加强学生培训。本项目研究了在连续切削过程中应用低频振动可以改变和改善切削力学和动力学的机制。沿沿着刀具进给方向以低频调制刀具将连续切削转变为离散切削。这种新的离散切削运动学不仅改变了切屑形成的变形力学，而且改变了切削区的热机械动力学以及加工过程的动态稳定性。本研究将通过原位数字图像相关分析切屑形成机理，并开发分析模型，以了解振动运动学（包括切削力和能量）与整体材料去除效果之间的关系。由于低频调制周期性地使切削刀具与工件分离，因此它中断了切削刃的连续加热，并引起预定的冷却时间段以降低刀具温度。分析模型和实验表征将捕捉这种瞬态和循环热传导制度及其热力学。它将提供最佳的切削策略，以增加刀具寿命。最后，将研究进给调制对过程和加工设备的耦合动力学的影响。将创造新的知识，如何使用受控的低频振动，以控制和抑制高频自激颤振不稳定性在加工过程中。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 Opportunities for Academic Liaison with Industry (GOALI) project partners two universities with industry in the fundamental research on the effect of applying slow vibrations to enhance material removal in machining processes. Vibrations have been treated as a disturbance and a source of inefficiency to many manufacturing operations including machining processes. However, this new approach attempts to use low frequency (slow) vibrations to improve the contact conditions between the cutting tool and workpiece and thereby improve machining efficiency. By applying controlled slow oscillations to cutting tools, this new cutting process can enable material removal with lower cutting effort and energy, attain longer tool-life, and improve overall stability of the machining process towards higher material removal rates. It can significantly enhance manufacturing productivity, and hence US competitiveness and prosperity, and product quality especially for components made of difficult-to-cut metal alloys employed in U.S. automotive, aerospace, defense and energy sectors. Collaboration with a partner from US automotive industry will help ensure the technology transfer and enhance student training.This project investigates the mechanisms by which low frequency vibration applied in continuous cutting process can alter and improve the cutting mechanics and dynamics. Modulating the tool at low frequency along tool feed direction transforms continuous cutting into discrete cutting. This new discrete cutting kinematics not only alters the deformation mechanics of chip formation, but also changes the thermomechanical dynamics in the cutting zone as well as the dynamic stability of the machining process. This research will analyze chip formation mechanics through in-situ digital image correlation and develop analytical models to understand the relationship between vibration kinematics, including cutting force and energy, and overall material removal effort. As the low frequency modulation periodically disengages the cutting tool from the workpiece, it interrupts continuous heating of the cutting edge and induces pre-determined cool-down periods to reduce tool temperature. Analytical models and experimental characterization will capture this transient and cyclic heat conduction regime and its thermo-mechanics. It will provide optimal cutting strategies to increase the tool-life. Finally, effect of feed modulation on the coupled dynamics of process and the machining equipment will be investigated. New knowledge will be created on how to use the controlled low frequency vibration to control and suppress high-frequency self-excited chatter instabilities during machining. It will allow machining of precision parts at significantly higher depth, feed and speed leading to greater material removal rates.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.