Power spectrum density characterization of grinding wheel surface in ultrasonic vibration spiral grinding
-
摘要: 超声振动螺线磨削过程中,砂轮表面微观形貌的变化复杂。为准确表征其特征,采用功率谱密度分析方法,将砂轮表面的微观结构分解为不同频率、振幅和相位的谐波,对比分析不同磨削行程时普通磨削和超声振动螺线磨削砂轮表面的磨损行为。结果表明:砂轮表面功率谱密度曲线的斜率k随着磨削行程的增大而逐渐减小,即k越小砂轮表面磨损越严重。其中,在早中期磨削阶段(行程不超过60次),超声砂轮表面的斜率k明显大于普通砂轮表面的,而在中后期超声砂轮表面的斜率k下降的速率显著高于普通砂轮表面的,该变化趋势揭示了2种磨削方式下砂轮表面有效磨粒数和砂轮堵塞的变化规律。进一步分析发现磨粒磨平和脱落使得磨粒功率谱密度占比减小,砂轮堵塞使得功率谱密度曲线的总体能量值增大。在早中期磨损阶段,超声振动螺线磨削砂轮表面的有效磨粒数多于普通磨削砂轮表面的,而在中后期其砂轮堵塞情况比普通磨削砂轮的更显著。Abstract: During the ultrasonic vibration spiral grinding process, the surface topography of the grinding wheel varies complicatedly. To accurately characterize the characters of the grinding wheel surface, a power spectral density (PSD) analysis method was adopted by decomposing the microstructure of the grinding wheel surface into harmonics of different frequencies, amplitudes and phases. The wear behaviors of the grinding surfaces after conventional grinding and ultrasonic vibration grinding in different grinding stages were compared and analyzed by using the PSD analysis. The results show that the slope k of the surface PSD curve of the grinding wheel gradually decreases with the increase of the grinding stage, which means that a smaller k represents more serious surface wear of the grinding wheels. Moreover, in the early wear stage, the slope k of the ultrasonic grinding wheel surface is significantly larger than that of the conventional grinding wheel surface, but in the later wear stage, the decline rate of the slope k of the ultrasonic grinding wheel surface is significantly higher than that of the conventional grinding wheel surface. This trend reveals the variation of the effective number of abrasive grains and the wheel loading on the grinding wheel surface under two different grinding methods. Further analysis reveals that the ground flat and pulled-outs of the abrasive grains decrease the proportion of the power spectral density of them, and the wheel loading increases the overall energy value of the PSD curve. In the early wear stages, the number of effective abrasive grains on the ultrasonic vibration grinding wheel surface was larger than that of the conventional grinding surface, whereas in the later stages, the grinding wheel loading in ultrasonic vibration grinding is more significant.
点击查看大图
计量
- 文章访问数: 182
- HTML全文浏览量: 22
- PDF下载量: 24
- 被引次数: 0