Thermal drift in laser cutting of metallic mesh structures

金属网状结构激光切割中的热漂移

• 批准号: 424264718
• 负责人: Professor Dr.-Ing. Frank Vollertsen
• 金额: --
• 依托单位: BIAS - Bremer Institut für Angewandte Strahltechnik GmbH
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424264718?language=en
• 关键词: Thermal; drift; laser; cutting; metallic

The trend towards higher product complexity requires to broaden the understanding of manufacturing technologies to rise to challenges in research and industrial production. This trend is among others observed in the field of audio systems like sound transducer or in the field of surface analysis like electron spectroscopy. For the letter, the central component is a mesh calotte, which is used as an electron-optical lens to focus electron beams. Such components are formed mesh structures, which are manufactured by laser machining and additional deep drawing. The mesh structures consist of thin webs, which show low stiffness and are limited in heat transfer. Unsuitable laser scan strategies lead to heat accumulation and consequently to thermal expansion of the material. This results in a deviation in web widths and deteriorates the quality of such mesh structures. Therefore, laser machining of thin metal sheets needs new techniques and methods to solve those challenges. So far, only local aspects in laser machining were addressed. It was shown for laser machining that e.g. surface integrity highly depends on ambient medium and scan speed of the laser, whereas heating in the material depends on pulse duration, fluence and repetition rate. Little notice has been given to the global thermal drift of thin metal sheets during laser machining. Particularly, when many notches and microstructures are produced on large thin metal sheets. It can be derived from the own preliminary studies that especially the global laser scan strategy has a significant effect on heat accumulation. So far, no methodology exists, which describes the thermal drift in mesh structures in dependence of the laser scan strategy to be able to take advantage of this behaviour. It is assumed that a suitable scan strategy leads to a low temperature deviation in the metal sheet, which results in an even thermal drift and accordingly to more regular web widths and notches.

更高产品复杂性的趋势要求扩大对制造技术的理解，以应对研究和工业生产中的挑战。这一趋势在音频系统领域(如声音换能器)或表面分析领域(如电子光谱学)中被观察到。字母的中心部件是网状卡洛特，它被用作电子光学透镜来聚焦电子束。这样的部件是形成的网格结构，通过激光加工和额外的深拉深制造。网状结构由较薄的腹板组成，刚度低，传热有限。不适当的激光扫描策略会导致热积累，从而导致材料的热膨胀。这导致了幅材宽度的偏差，并恶化了这种网状结构的质量。因此，金属薄板的激光加工需要新的技术和方法来解决这些挑战。到目前为止，只涉及激光加工中的局部方面。研究表明，对于激光加工，表面完整性高度依赖于环境介质和激光的扫描速度，而材料中的加热则取决于脉冲持续时间、通量和重复频率。金属薄板在激光加工过程中的整体热漂移问题还没有引起足够的重视。尤其是当在大而薄的金属板上产生许多缺口和微观组织时。从自己的初步研究可以得出，特别是全球激光扫描策略对热积累有显着影响。到目前为止，还没有方法来描述网格结构中的热漂移，这取决于激光扫描策略，以便能够利用这一行为。假设适当的扫描策略导致金属板中的低温偏差，这导致均匀的热漂移，并相应地产生更规则的腹板宽度和缺口。