基于动态力学模型分析的钛合金切削过程进给量对表面质量的影响规律

Influence of Feed on Surface Quality in Titanium Alloy Cutting Process Based on Dynamic Mechanical Model Analysis

目的建立单自由度工件-刀具振动系统动力学模型,定量研究进给量对钛合金Ti-6Al-4V切削力和振动加速度的影响规律。方法采用改变进给量的单因素试验,选用涂层硬质合金刀具车削钛合金Ti-6Al-4V,通过DYTRAN加速度传感器、YDCB-Ⅲ05三向压电测力系统对试验过程中切削振动和切削力进行检测,运用MATLAB、Origin软件对采集的振动加速度和切削力信号进行处理和分析,采用120mm位相光栅干涉粗糙度轮廓仪(Talysurf PGI840)测量其表面粗糙度。结果当进给量分别为0.1、0.15、0.2、0.24、0.3 mm/r时,振动加速度的均方根分别为0.2413g、0.3299g、0.3945g、0.4468g、0.5737g;算数平均高度Ra分别为0.5383、0.9391、1.4781、1.9849、3.0117μm;平均谷深度Rz分别为3.1846、4.6445、6.3059、8.3383、11.6506μm,随进给量的增大,切削力、振动加速度和表面粗糙度均增大。结论当刀具进给量增大时,刀具与工件之间的接触面积增大,摩擦力增大,从而引起切削力稳态分量的增大,根据单自由度工件-刀具振动系统动力学模型可知,切削力稳态分量增大,切削振动加速度随之增大,会使刀尖位移增大,造成表面粗糙度值随着进给量的增大而增大。

The work aims to establish the dynamic model of single-degree-of-freedom in workpiece-tool vibration system so as to quantitatively study the influence of feed on cutting force and vibration acceleration of titanium alloy Ti-6Al-4V. The single factor test of changing the feed rate was adopted. Ti-6Al-4V titanium alloy was turned by coated hard alloy tool. The cutting vibration and cutting force in the cutting process were tested by DYTRAN acceleration sensor and YDCB-II105 three-dimensional piezoelectric force measuring system. The collected vibration acceleration and cutting force signals were processed and analyzed by MATLAB and Origin software. The surface roughness was measured by 120 mm Talysurf PGI840 roughness tester. When the feed rates was 0.1, 0.15, 0.2, 0.24 and 0.3 mm/r, respectively, the mean square roots of the vibration acceleration were 0.2413g, 0.3299g, 0.3945g, 0.4468g and 0.5737g, respectively, the average arithmetic heights of Ra was 0.538, 0.9391, 1.4778, 1.984 and 3.0117 μm, respectively and the average valley depth Rz was 3.1846, 4.64445, 6.3059, 8.338 and 11.6506 μm, respectively. With the increase of the feed, all of the cutting force, vibration acceleration and the surface roughness increased. The contact area between the tool and the workpiece increases with the increase of feed rate, which leads to the increase of the friction force and the steady-state component of the cutting force. From the dynamic model of the workpiece- tool vibration system, the vibration acceleration increases with the increase of the steady-state component of the cutting force, thus causing bigger tip displacement and resulting in that the surface roughness increases with increase of the feed rate.