脉冲光纤激光修锐青铜金刚石砂轮等离子体特性研究

Plasma characterization studies of laser dressing for bronze-bonded diamond wheel by a pulsed fiber laser

采用光栅光谱仪对脉冲光纤激光修锐青铜金刚石砂轮过程中产生的等离子体空间分辨发射光谱进行了测量.研究了500—600nm波段范围内的等离子体空间发射光谱强度随激光平均功率和脉冲重复频率的变化情况.结果表明:等离子体辐射光谱强度在其径向膨胀方向上距离砂轮表面约2.4mm处达到最大值.在局部热力学平衡假设条件下,根据等离子体中六条铜原子谱线的相对强度,利用Boltzmann图法,计算得到在不同激光功率和重复频率条件下的等离子体电子温度沿砂轮径向方向的分布规律.实验结果表明:在激光修锐青铜金刚石砂轮过程中,距离砂轮表面约3mm处等离子体电子温度出现峰值,其温度最高可达4380K,且等离子体电子温度随着激光参数和空间位置的改变呈现出不同的演变规律.

In this paper, we present the optical emission studies of the spatial evolution of plasma during pulsed fiber laser dressing of bronzebonded diamond grinding wheel and especially investigate the plasma light emission, which is measured through a high sensible optical spectrometer. Space-resolved spectra in a wavelength range of 500–600 nm are measured at different laser average powers and pulse repetition frequencies, and the intensity of spectral lines achieves a maximum intensity at about 2.4 mm away from the surface of the grinding wheel. The electron temperature is determined by employing the Boltzmann plot method under the assumption of local thermodynamic equilibrium using six Cu （I） lines, and the highest electronic temperature is calculated to be 4380 K at about 3 mm away from the surface of wheel. Finally the effect of the laser parameters on the electron temperature of the plasma is studied, and the results show that there are different variation laws in the electron temperature of the plasma with laser average power and pulse repetition frequency.