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

GOALI项目是两所大学与工业界在应用慢速振动以提高机械加工过程中材料去除效果的基础研究方面的合作伙伴。振动一直被视为包括机械加工在内的许多制造作业的干扰和低效来源。然而，这种新的方法试图使用低频(慢)振动来改善刀具和工件之间的接触条件，从而提高加工效率。通过对刀具应用受控的慢摆动，这种新的切割工艺能够以更低的切削力和能量去除材料，获得更长的刀具寿命，并提高加工过程的整体稳定性，从而获得更高的材料去除率。它可以显著提高制造生产率，从而提高美国的竞争力和繁荣，以及产品质量，特别是在美国汽车、航空航天、国防和能源部门使用的由难切割的金属合金制成的部件。与美国汽车行业的合作伙伴合作，将有助于确保技术转移和加强学生培训。本项目研究连续切割过程中应用低频振动改变和改善切割力学和动力学的机理。将刀具沿进给方向进行低频调制，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机理，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。这项研究将通过现场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，与整体材料去除努力之间的关系。由于低频调制周期性地使刀具从工件上脱离，它中断了对刀具刃口的连续加热，并导致预定的冷却时间以降低刀具温度。分析模型和实验表征将捕捉到这种瞬变和循环热传导机制及其热力学。它将提供最佳的切割策略，以提高刀具寿命。最后，研究了进给调制对过程与加工设备耦合动力学的影响。在如何利用受控低频振动来控制和抑制加工过程中的高频自激颤振不稳定性方面将创造新的知识。它将允许在更高的深度、进给量和速度下加工精密零件，从而产生更高的材料去除率。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.