整形飞秒激光精密微加工技术研究

发布时间：2018-03-15 06:25

本文选题：整形飞秒激光　切入点：精密加工　出处：《吉林大学》2016年博士论文　论文类型：学位论文

【摘要】：飞秒激光对材料的超精细加工是飞秒激光技术在材料加工领域的一个重要应用。飞秒激光超精细微加工与先进的器件制造技术紧密相关,对国防、医疗和工业加工等领域的发展起到了直接的推动作用。飞秒激光对不同材料的微加工过程,其物理机制研究涉及到原子分子物理、材料科学和等离子体物理等不同学科的交叉。因而研究飞秒激光对不同材料的微加工过程不仅对其物理机制的理解具有重大的意义,而且对材料的微加工应用也有指导作用。通过发展新的激光操控手段(飞秒激光整形技术),并研究整形激光对不同材料的微加工过程,有助于增加人们对材料加工过程的理解,同时也有助于发展新的微加工手段,提高材料微加工的精度和速度。基于对激光聚变靶材微孔加工的应用需求,本论文将飞秒激光脉冲整形技术应用于不同材料的精密微加工,对飞秒激光双脉冲和整形激光脉冲作用下金属材料、碳氢聚合物材料薄膜以及碳氢聚合物材料微球的烧蚀机制和微孔加工精度进行了大量的研究。论文的主要内容包括:利用飞秒激光双脉冲研究了金属铝和铜的钻孔过程。通过分析钻透样品的透射光信号和微孔形貌图,详细讨论了铝和铜在飞秒激光作用下的烧蚀机制。通过对两种金属的烧蚀形貌观测,发现孔直径随着双脉冲延迟时间增加而减小,钻孔速度随着延迟时间增加而变慢。在短延迟时间内在孔周围有大颗粒的沉积物,而在长延迟时间内在孔周围只有细小的沉积物。研究发现等离子体的屏蔽作用在孔的形成和纳米颗粒产生都有重要作用,同时还发现在铝的钻孔过程中氧化物的形成也会对烧蚀产生影响。通过改变整形飞秒激光脉冲形状、激光重复频率、激光偏振、激光能量通量和激光焦点距样品表面位置等实验条件对金属铜箔进行了钻孔研究。我们测量了不同实验条件下激光的透射信号和铜箔的烧蚀形貌,探究了金属材料的烧蚀机制,并最终获得了实现高质量圆微孔的微加工技术。研究发现,利用脉冲间隔td=0.6 ps的五脉冲序列钻孔可以获得较少喷溅物的微孔,高重复频率的激光脉冲作用可以减小喷溅物的颗粒尺寸,圆偏振激光脉冲钻孔可以获得圆度很好的微孔。通过反复优化实验条件,可以获得尺寸小、圆而且入口和出口尺寸接近并且孔周围无明显喷溅物的微孔。在整形飞秒激光脉冲烧蚀辉光放电聚合物平面薄膜的研究中,我们发现激光的脉冲形状对聚合物材料的烧蚀效率和精度有非常重要的影响,利用整形脉冲可以提高薄膜的加工效率和精度。研究还发现在真空环境下加工可以得到无明显喷溅物的微孔。材料加工效率和精度与激光的焦点位置也有着非常重要的关系,当激光先聚焦后作用在样品表面时会得到“小”而“圆”的微孔。通过在实验中选择合适的焦点位置,可以极大程度的优化烧蚀效率并得到高精度的微孔。我们采用膜加玻璃基底的组合方法来模拟聚合物材料微球的前表面和内表面;通过对烧蚀之后的基底进行表征,成功的模拟了烧蚀过程中微球内部喷溅物的产生情况,并且获得了微球内壁无损伤的加工条件。通过对烧蚀后的基底进行表征,发现在真空度为2.5 Pa和激光能量为6.0μJ时利用多个子脉冲组成的脉冲序列钻孔,不仅可以减少在微孔加工过程中向微球内壁的喷溅物而且可以减小激光对微球内壁的加工热影响区域,并获得了高质量微孔。当激光能量降低到4.0μJ时,已经完全观察不到激光对基底的烧蚀痕迹。所以用此能量进行微孔加工可以得到更高质量的微孔,从而不影响微球在激光聚变中的进一步应用。在整形飞秒激光脉冲对聚合物材料微球的微孔加工中,我们建立了微球空间定位技术,确保激光的入射方向严格垂直于球表面、通过球心。在此基础上,我们进行了整形飞秒激光对不同壁厚微球的烧蚀钻孔研究。发现钻透不同厚度的样品所需要的最低能量不同。随着钻孔深度的增加,激光在孔内传递过程发生的反射、折射和散射等过程,激光传递到孔底部进行烧蚀的激光能量降低,导致钻透越厚的微球所需激光能量越高。我们成功的实现了微球上高质量的微孔加工,研究还发现利用整形激光脉冲可以大大提高微球的加工精度,通过飞秒激光整形技术可以实现对微球的超精细加工,制备可用于实际应用的微球靶。以上的研究表明,飞秒激光脉冲整形技术应用于材料的微加工,增加了加工过程的操控手段,可以根据实际需要设计出合适的整形激光以获得最好的加工条件,从而大大提高材料的加工精度。因而,飞秒激光整形技术可以被广泛的应用于不同材料的微加工应用和研究中。
[Abstract]:The ultra fine processing of femtosecond laser materials is an important application of femtosecond laser technology in the field of material processing. Femtosecond laser micro machining and advanced device manufacturing technology is closely related to the development of national defense, medical and industrial processing and other fields has played a direct role in promoting. Femtosecond laser micro processing of different materials Study on the process, the physical mechanisms involved in atomic and molecular physics, plasma physics and material science across different disciplines. Therefore not only on the physical understanding of the mechanism is of great significance to research on femtosecond laser micro machining process for different materials, but also has a guiding role for micromachining applications materials. Through the development of new laser manipulation (the femtosecond laser shaping technology), and Research on different materials of plastic laser micro machining process, help to increase our understanding of the material processing, at the same time Can also contribute to the development of new micro machining tools, improve micro machining accuracy and speed. The application requirement of laser fusion targets based on micro processing, the application of femtosecond laser pulse shaping technology in different materials precision micro machining, the femtosecond double pulses and shaping laser pulses of metal material, hydrocarbon the polymer film and polymer microsphere hydrocarbon ablation mechanism and micro hole machining precision was studied. The main contents of this paper include: femtosecond double pulses of drilling metal aluminum and copper process. Through the analysis of drilling using optical signal transmission and microporous morphology through the sample, the ablation mechanism of aluminum and copper in effect femtosecond laser is discussed in detail. The ablation morphology observation of two kinds of metal, found the hole diameter with double pulse delay time decreases with the extension of drilling speed Late time increased slowly. There are large particles of sediment in a short time delay inherent around the hole in the long delay time, the inner holes around the small sediment. The study found that the shielding effect of the plasma at the pore formation and nano particles have an important role, but also it formed in the drilling process of aluminum oxide will have an impact on the shaping of femtosecond laser ablation. By changing the shape of the pulse repetition frequency, laser, laser polarization, laser energy flux and laser focus from the sample surface position of experimental conditions on the metal foil for drilling research. We measured the transmission signal and the laser ablation morphology of copper under different experimental conditions, to explore the ablation mechanism the metal materials, and finally got the micro processing technology to achieve high quality round micropores. The study found that using five pulse sequence drilling pulse interval td=0.6 PS You can get fewer splashes of micropores, particle size of laser pulses with high repetition frequency can reduce the spatter, circularly polarized laser pulse drilling can obtain good roundness of microporous. Through repeated optimization of experimental conditions, the size of small, round and entrance and no obvious micropore splashes around the hole and close mouth size in the study of ablation of glow discharge polymer thin film laser pulse shaped femtosecond laser, we found a very important influence on the shape of pulse laser ablation of polymeric materials by pulse shaping efficiency and accuracy, improve processing efficiency and accuracy of the film. The study also found that the processing in vacuum environment can be obtained without obvious pores splashings the focus position. The efficiency and accuracy of material processing and laser also has a very important relationship. When the laser focusing effect on the surface of the sample when Will be "small" and "circle". By choosing appropriate micropore focus position in the experiment, we can optimize the ablation efficiency greatly and has high precision. The combination method of microporous membrane and glass substrate we used to simulate the polymer microspheres and the front surface and the inner surface; characterized by basement after ablation the successful simulation of the production of microspheres in the ablation process of internal splashes, processing conditions and access to the wall without damage. The microspheres were characterized on the substrate after ablation, found in the vacuum is 2.5 Pa and the laser energy is 6 J using multiple sub pulse sequence pulse drilling, not only in the micro machining process can be reduced to the inner wall of the microspheres splashes and reduce the heat on the inner wall of the laser processing microspheres affected areas, and obtain high quality microporous. When the laser energy is reduced to 4 J, was not observed on the basis of the laser ablation. So this energy can be obtained with micropore micropore with higher quality, so as not to affect the further application of microsphere in laser fusion. In the shaping of femtosecond laser pulse micro processing on polymer material microspheres, we established microspheres space positioning technology sure, strictly perpendicular to the incident direction of laser surface through the center. On this basis, we conducted research on ablation drilling with different thickness of microspheres shaping of femtosecond laser. It is found that the lowest energy drill through different thickness samples need different. With the increase of the drilling depth, laser transmission reflection process occurs in the hole in the refraction and scattering process, the laser energy transfer to laser ablation at the bottom of the hole is reduced, resulting in drilling through the thick of the microspheres required laser energy is high. We successfully The microspheres on high quality micro processing, the study also found that the use of laser pulse shaping can greatly improve the machining precision of microspheres by femtosecond laser shaping technology can achieve ultra precision machining of the microspheres, preparation for microsphere applications. All above results show that the micro processing of femtosecond laser pulse shaping technology application in materials that increase process control means, according to the design of plastic laser suitable to obtain the best processing conditions of the actual needs, thus greatly improve the machining precision of materials. Therefore, femtosecond laser shaping technology can be widely used in micro machining of different materials in application and research.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O437

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