影响铣削颤振稳定性的因素与规律分析

摘要

应用Altintas切削颤振理论实现了铣削颤振的预测,并对影响铣削稳定性的机床系统因素进行了分析.研究发现,稳定性叶瓣图会受到机床的主轴-刀具系统模态参数影响,尤其是模态刚度、 阻尼比和固有频率.另外,通过系统动刚度相同的条件下不同的阻尼比和模态刚度组合对铣削稳定性的影响分析发现,模态刚度对系统稳定性的影响要大于阻尼比的影响程度.分别对影响铣削加工稳定性的刀具参数、 工件材料特性以及切削参数等因素及其对铣削稳定性的影响规律进行了分析.结果显示:减小刀具齿数、 刀具螺旋角和刀具悬伸量,并增大刀具直径对于改善切削颤振有益;具有较小切向切削力系数和径向切削力系数的材料更容易实现稳定切削;减小铣削宽度,并采用顺铣方式,系统的临界切深更大.%The influence factors of machine tool system on milling stability are analyzed using the Altintas 's machining chatter the-ory for realizing forecast .It was found in study that milling stability lobes would be influenced by mode parameters of spindle -tool sys-tem, especially as mode stiffness, damping ratio and natural frequency .In addition, through the analysis of the influence of system dy-namic stiffness under the same combination with different damping ratio and modal stiffness on milling stability , it was found that the influence of modal stiffness on milling stability was greater than that of damping ratio .Tool parameters , material characteristic of work-piece, cutting parameters and their influence law on milling stability were analyzed separately .Results show that less tool teeth and smaller helix angle and tool elongation are helpful to avoid milling chatter , as well as enlarge tool diameter .Machining workpiece with smaller tangential and radial cutting coefficient of material can be more stable than the other .Also, there are larger critical cutting depths of the system with smaller cutting width and up milling method .