红松水导纳秒激光烧蚀机制及加工试验

Ablation Mechanism and Experiment of Korean Pine by Water-Jet Guided Nanosecond Laser

【目的】分析水导纳秒激光对木材表面的烧蚀机制,探讨有无水导系统参与下激光功率、切割速度对切缝宽度的影响,剖析木材切缝表面质量的影响因素,建立多元线性回归预测模型,为纳秒激光加工木材切缝宽度的预测提供理论依据。【方法】在介绍自行搭建水导纳秒激光试验台工作原理的基础上,分析水导纳秒激光对木材表面的烧蚀机制,深入剖析水射流与纳秒激光耦合作用下木材表面烧蚀的动态演化规律。以红松为材料进行水导纳秒激光加工切割试验,加工后多次测量切缝宽度取平均值。采用单因素试验方法,探讨有无水导系统参与下激光功率、切割速度对红松表面切缝宽度的影响;通过扫描电镜对加工后的红松切缝表面进行微观形貌表征,剖析有无水导系统参与下红松切缝表面质量;利用IBM SPSS Statistics 23对有水导系统参与下的试验数据进行多元线性回归分析,建立激光功率、切割速度、水流速度与红松表面切缝宽度的多元线性回归预测模型。【结果】切缝宽度随激光功率增加而增大,随切割速度增加而减小;当切割速度为50 mm·s^-1、激光功率为6 W时,无水导系统参与下红松表面切缝宽度最小为0.53 mm,有水导系统参与下红松表面切缝宽度最小为0.31 mm。切缝表面微观形貌表征显示,无水导系统参与下红松管胞内壁留有残留物,平滑度低,表面粗糙;有水导系统参与下红松管胞内壁清晰,几乎没有残留物,表面平滑,表面质量良好。通过多元线性回归分析,获得激光功率、切割速度、水流速度与切割宽度的关系,所建立的多元线性回归预测模型具有较好预测精度。【结论】利用水导纳秒激光加工木材,应控制好工艺参数与切缝宽度的关系,当切割速度较大、激光功率较小时,可获得最小切缝宽度。有水导系统参与相比无水导系统,切缝表面质量更好。

【Objective】This paper aimed to study ablation mechanisms on the surface of limber processed by water-jet guided nanosecond laser,and to discuss the influences of laser power and cutting speed on cutting width,with or without water-jet guided system.Additionally,it aimed to obtain the relationships of laser power,cutting speed and cutting width,and to analyze the influence factors of the surface quality of Korean pine.【Method】On the basis of introducing test bench of water-jet guided nanosecond laser,the ablation mechanisms on the surface of Korean pine processed by water-jet guided nanosecond laser was researched,and the coupling mechanisms of water jet and nanosecond laser on the surface of the Korean pine was deeply analyzed;the experiment of water jet-guided nanosecond laser cutting Korean pine was carried out;Korean pine was used as the materials,the cutting width of Korean pine was repeatedly measured and average value was obtained.By adopting the method of single factor experiment,with or without water-jet guided system,the influences of different laser powers and cutting speeds on cutting width was discussed;the morphology of the surface of the cutting width was observed by scanning electron microscopy(SEM);the experimental data was processed through the multiple linear regression analysis by the IBM SPSS Statistics 23,and the predicted model was established.【Result】Cutting width increased with the increase of laser power,and decreased with the increase of cutting speed.Without water-jet guided system,when the cutting speed of 50 mm·s^-1 and laser power of 6 W,minimum cutting width of Korean pine surface was 0.53 mm;with water-jet guided system,when the cut speed of 50 mm·s^-1 and laser power of 6 W,minimum cutting width of Korean pine surface was 0.31 mm.Through the observation of cutting surface morphology,without the water-jet assisted system,some residues were left on the inner walls of tracheids,and cutting surface was rough;with the water-jet assisted system,nearly no residues were left on the inner walls of tracheids,the cutting surface was smooth and the surface quality of Korean pine cutting was better.Through multiple linear regression analysis,the relationships of laser power,cutting speed and cutting width was obtained.The prediction model had a good prediction precision.【Conclusion】The relationships between the process parameters and the cutting width should be controlled when processing water-jet guided nanosecond laser machining wood.When the cutting speed is larger and laser power is smaller,a minimum cutting width could be obtained.Compared with the without water-jet guided system,the surface quality of Korean pine with water-jet guided system would be better.