Increase in process efficiency of laser chemical machining by preventing the gas bubble related removal disturbances

通过防止与气泡相关的去除干扰来提高激光化学加工的工艺效率

基本信息

批准号：
403820352
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：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/403820352?language=en
关键词：
Increase process efficiency laser chemical

项目摘要

Laser chemical machining (LCM) is a further development of the electrochemical processing and is based on the laser-induced anodic material dissolution at the interface workpiece-electrolyte. Thereby, the process is characterized by its flexibility and variety, its gentle and residue-free removal as well as its low thermal load on the workpiece. Using suitable material-electrolyte combinations and energy inputs structures of < 50 μm and surface roughness of up to 0.1 μm can be realized. However, the low processing speed (<1·e-2 mm3/min) is still representing the main disadvantage of LCM-process and poses an obstacle for an industrial application. This can be reduced to the fact that purely laser chemical machining takes place in a very restricted process window, which is limited by the rapid achievement of the electrolyte boiling point. Due to high induced temperatures the intensified formation of boiling bubbles exerts a shielding effect in the interaction zone and leads to a disturbance of the material removal.The aim of this project is therefore to further increase process efficiency and quality of the laser chemical removal. In order to avoid the formation of gas bubbles the process should be carried out in higher ambient pressures. Thereby it is assumed that the increase of the electrolyte boiling point due to rising ambient pressure leads to a reduction in gas bubble size as well as to an increase in the removal rates. Thus, the process window for disturbance-free laser chemical removal can be broadened.For this purpose, a suitable process cell should be developed to ensure a safe processing at high ambient pressures. In dependence of the process relevant parameters, e.g. ambient pressure the properties of the laser chemical removal (removal depth, width, and surface quality) should be then characterized. Besides, the pressure-dependent process windows, within which a disturbance-free removal can be realized reproducibly, are to be identified. For a better understanding of the removal mechanisms the temperature-related transitions of the boiling regimes as well as the behavior of the interaction zone with and without laser beam exposure should be visualized. Thus, the relationships between the boiling properties and the resulting removal disturbances could be demonstrated and clarified. The findings to be obtained should then feed into a model-like description of the LCM removal mechanisms, which should be based on the analytical computation of the laser-induced temperature fields on the workpiece surface and their direct correlation with the resulting removal geometries.

激光化学加工（LCM）是电化学加工的进一步发展，基于激光诱导工件-电解质界面处的阳极材料溶解，因此该工艺具有灵活性和多样性、温和且无残留的特点。然而，使用合适的材料-电解质组合和小于 50 μm 的能量输入结构以及高达 0.1 μm 的表面粗糙度是可以实现的。低加工速度（<1·e-2 mm3/min）仍然是 LCM 工艺的主要缺点，并且对工业应用构成障碍。这可以归结为纯激光化学加工发生在一个事实。该工艺窗口受到电解质沸点快速达到的限制，由于诱导温度高，沸腾气泡的强化形成在相互作用区域中产生屏蔽效应，并导致材料去除的干扰。因此，这个项目是为了进一步提高激光化学去除的工艺效率和质量，为了避免气泡的形成，该工艺应该在较高的环境压力下进行，因此假设电解质沸点由于环境压力升高而增加。导致气泡尺寸减小以及去除率增加，因此，可以拓宽无干扰激光化学去除的工艺窗口。为此，应开发合适的工艺单元以确保安全。在高环境压力下进行处理。然后，应表征工艺相关参数，例如环境压力、激光化学去除的特性（去除深度、宽度和表面质量）。此外，还应表征压力相关的工艺窗口，在该窗口内可以重复地实现无干扰去除。为了更好地理解去除机制，沸腾状态的温度相关转变以及有和没有激光束照射的相互作用区域的行为应该被可视化。因此，沸腾特性之间的关系应该被可视化。以及由此产生的移除然后，可以证明和澄清所获得的结果，并将其输入 LCM 去除机制的模型描述中，该描述应基于工件表面激光诱导温度场及其直接相关性的分析计算。以及由此产生的去除几何形状。