Double-pulse technique for short pulse laser drilling
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摘要: 为了提高纳秒短脉冲激光微孔制备的加工效率,采用了一种新颖的双脉冲方法。通过时域脉冲塑形将调Q激光器产生的普通纳秒脉冲变换为具有几十纳秒脉冲时间间隔的双脉冲序列。使用这种双脉冲序列对不锈钢试件进行打孔实验,与传统单脉冲打孔结果对比发现,在一定条件下双脉冲序列能将打孔烧蚀率提高一个数量级以上。实验中研究了脉冲能量、重复频率以及环境气体压力对双脉冲序列烧蚀率的影响,并将脉冲烧蚀率提高的原因归结为材料预加热、材料溶液的加速以及瞬时准真空环境,对各种机制分别进行了讨论。结果表明,采用双脉冲方法替代普通单脉冲进行金属打孔,可以在相同能量密度,相同脉冲重复频率的情况下大幅度提高脉冲烧蚀率,为高效激光微孔制备提供了新方法。Abstract: In order to improve the efficiency of short pulse laser drilling,a double-pulse technique is put forward.The double-pulse herein represents two neighboring nanosecond pulses with several tens of nanoseconds interpulse separation,acquired by temporal pulse shaping.In the experiments,laser beams from a Q-switched Nd: YLF laser was focused on steel workpieces 0.4mm~1.0mm thick.The influence of energy density,repetition rate and the ambient gas pressure on ablation rate was studied. Che experimental results show a significant enhancement of ablation rates using double-pulse instead of conventional single-pulse under the same condition of energy density and pulse repetition frequency.The ablation mechanism of the double-pulse drilling,intauding material preheating,melt flow accelerating and quasi-vacuum environment,was discussed respectively.These results are important for practical efficient laser drilling.
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Keywords:
- laser technique /
- laser drilling /
- douhle-pulse /
- pulse shaping /
- ablation rate
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[1] BREITLING D,RUF A,DAUSINGER F.Photon processing in microelectronics and photonics Ⅲ[J].Proc SPIE,2004,5339:49-63.
[2] JACKSON M J,NEILL W O.Laser micro-drilling of tool steel using Nd:YAG lasers[J].Journal of Materials Processing Technology,2003,142(2):517-525.
[3] BREITLING D,SCHITTENHELM H,BERGER P,et al.Shadowgraphic and interferometric investigations on Nd:YAG laser-induced vapor/plasma plumes for different processing wavelengths[J].Appl Phys,1999,A69(s1):505-508.
[4] KLIMENTOV S M,KONONENKO T V,PIVOVAROV P A,et al.Roleof gas environment in the process of deep-hole drilling by ultrashort laser pulses[J].Proc SPIE,2003,4830:515-520.
[5] FIERET J,TERRY M J,WARD B A.Aerodynamic interactions during laser cutting[J].Proc SPIE,1986,668:53-62.
[6] ST-ONGE L,DETALLE V,SABSABI M.Enhanced laser-inducedbreakdown spectroscopy using the combination of fourth-harmonic and fundamental Nd:YAG laser pulses[J].Spectrochimica Acta,2002,B57(1):121-135.
[7] SCAFFIDI J M,ANGEL S,CREMERS D A.Emission enhancementmechanisms in dual-pulse LIBS[J].Analytical Chemistry,2006,78(1):24-32.
[8] STRATIS D N,ELAND K L,ANGEL S M.Effect of pulse delay time on a pre-ablation dual-pulse LIBS plasma[J].Applied Spectroscopy,2001,55(10):1297-1303.
[9] SATTMANN R,STURM V,NOLL R.Laser-induced breakdown spectroscopy of steel samples using multiple Q-switch Nd:YAG laser pulses[J].J Phys,1995,D28(10):2181-2187.
[10] LEHANE C,KWOK H S.Enhanced drilling using a dual-pulse Nd:YAG laser[J].Appl Phys,2001,A73(1):45-48.
[11] WANG J J.Laser processing technique[M].Beijing:China Metrology Pubeishing House,1992:114-115(in Chinese).
[12] PETTER L,NOLL R.Material ablation and plasma state for single and collinear double pulses interacting with iron samples at ambient gas pressures below 1bar[J].Appl Phys,2007,B86(1):159-167.
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