Transient Multi-Phase Modelling of Process Dynamics in Ultrafast Laser Ablation of Metals

金属超快激光烧蚀过程动力学的瞬态多相建模

• 批准号: 245510492
• 负责人: Professor Dr.-Ing. Michael Schmidt
• 金额: --
• 依托单位: Lehrstuhl für Photonische Technologien (LPT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/245510492?language=en
• 关键词: Transient; Multi; Phase; Modelling; Process

At the background of an increasing application of ultrafast laser systems in industrial production and latest progress in process simulation of laser based manufacturing techniques in the frame of the research project a numerical multi-phase simulation model for ultrafast laser ablation of metals, that images the transient dynamics of ablation and structuring processes with nano-, pico- and femtosecond laser pulses, shall be developed.The research effort is structured in four work packages that build up on one another. Based on the initial development of a numerical description for the absorption, heat conduction and ablation processes during the interaction of ultrashort laser pulses with metals, complete structuring processes shall be regarded. In the description of the absorption of ultrashort laser pulses on the surface of the workpiece, in the material volume and in the occurring plasma, besides a consideration of the changing optical properties with the temperature special focus lies on the modeling of nonlinear absorption phenomena. For the description of thermal processes during the interaction of ultrashort laser pulses with metals a heat conduction simulation based on the two-temperature model shall be developed, taking into account latent heats and temperature dependences in the thermal material properties. The modeling of the material ablation focuses on quantitative correct ablation volumes in the different pulse duration and fluence regions. Emanating from an incompressible description of the ablation process, a coupled compressible-incompressible multi-phase model for evaporation and plasma formation shall be implemented in the simulation. Finally, based on the developed model complex structuring processes with pulse sequences shall be regarded in order to image the influence of processing parameters (pulse duration, fluence, wavelength, pulse repetition rate) on the process and the processing result. These investigations are accompanied by extensive experimental analyses delivering the database and process knowledge for the model development. Besides, they serve for a verification of the developed models.The simulation model shall be used in order to characterize ablation processes of iron and copper with different pulse durations and laser wavelengths with respect to achievable structuring quality and ablation efficiency. Building up on a fundamental investigation of the beam-matter interaction processes, optimal processing parameters and processing strategies for the structuring with ultrashort laser pulses shall be identified. The simulation model shall set the base for a future simulation based process layout and planning in industrial ultrafast laser structuring.

在超快激光系统在工业生产中的应用日益广泛和基于激光制造技术的过程模拟的最新进展的背景下，在研究项目的框架内，开发了一个超快激光烧蚀金属的多相数值模拟模型，该模型成像了纳秒、皮秒和飞秒激光脉冲烧蚀和组织过程的瞬时动力学。在初步建立了超短激光脉冲与金属相互作用过程中吸收、热传导和烧蚀过程的数值描述的基础上，应考虑完整的结构过程。在描述超短激光脉冲在工件表面、材料体积和产生的等离子体中的吸收时，除了考虑光学性质随温度的变化外，特别关注的是非线性吸收现象的建模。为了描述超短激光脉冲与金属相互作用过程中的热过程，应建立基于双温度模型的热传导模拟，考虑材料热性质中的潜热和温度依赖关系。材料烧蚀的模拟主要集中在不同脉冲宽度和注量区的定量校正烧蚀体积。从烧蚀过程的不可压缩描述出发，在模拟中实现了蒸发和等离子体形成的可压缩-不可压缩多相耦合模型。最后，在所建立的模型的基础上，考虑了具有脉冲序列的复杂结构过程，以反映加工参数(脉冲宽度、通量、波长、脉冲重复率)对加工过程和加工结果的影响。这些调查伴随着广泛的实验分析，为模型开发提供了数据库和过程知识。此外，它们还用于验证所开发的模型。该模拟模型用于描述不同脉冲持续时间和不同激光波长的铁和铜的烧蚀过程，以达到可实现的结构质量和烧蚀效率。在对光束-物质相互作用过程的基础研究的基础上，将确定用于超短激光脉冲结构的最佳加工参数和加工策略。该仿真模型为未来基于仿真的工业超快激光成形工艺布局和规划奠定了基础。