钛合金Ti6Al4V铣削加工过程阻尼模型稳定性预报

Stability prediction on process damping model of milling of titanium alloy Ti6Al4V

钛合金的导热系数小、化学亲和性大,易与摩擦表面产生黏附现象,在加工过程中容易产生变形,导致切削力的波动,引起系统的振动。针对这种难加工材料,往往采取低速切削。在低速加工过程中,刀具与工件加工表面之间产生的过程阻尼对系统的稳定性影响尤为显著。以钛合金Ti6Al4V为研究对象,进行铣削加工实验,以基于摩擦颤振原理的过程阻尼模型为动力系统模型,给出其稳定性分析的全离散预报方法,得到的稳定性Lobe图与加工实验数据相吻合,有效地预报了钛合金Ti6Al4V在低切削速度条件下的加工稳定性,可以减少刀具磨损,提高加工质量。

This paper is focused on a full-discretization prediction method designed for the system stability analysis of the process damping model.The system stability is notoriously affected by process damping occurring between the cutting tool and the workpiece machining surface.The occurrence is attributed to low speed cutting necessary for treating titanium alloys,a difficult-to-machine material more likely to produce deformation and the consequent cutting force fluctuation responsible for the system vibration in the process of machining,all of which are due to the drawbacks inherent in titanium alloy,such as a smaller thermal conductivity coefficient,a greater chemical affinity,and the liability to produce adhesion with friction surface.The proposed method draws on a milling experiment of titanium alloy Ti6Al4V,works by dynamical system model developed from process damping model based on friction chatter principles and gives the stability lobe diagram consistent with experimental data,thus enabling an effective prediction of process stability of titanium alloy Ti6Al4V in low cutting speed and thereby contributing to reducing tool wear and improving machining quality.