Femtosecond laser-contoured micro-strain gages
Femtosecond laser-contoured micro-strain gages
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DOI：
10.1016/j.mee.2019.05.002
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发表时间：
2019-06-01
影响因子：
2.3
通讯作者：
Dietzel, Andreas
中科院分区：
文献类型：
--
作者：
von der Heide, Chresten;Grein, Maria;Dietzel, Andreas
一种基于箔的微应变计（mu SG）的新概念，传感器元件小于1毫米(2)，并通过激光轮廓加工成为可能。与光刻结构相比，激光烧蚀结构的应变片可以在应用应变传感器空白后精确地在其测量目的地定制。特别是用于测量空间非常有限的伸长的传感器，需要精确定位和小网格。精确的机械定位的测量网格在微米尺度可能是具有挑战性的，因为更大，笨重，箔基板。在激光烧蚀网格图案之前定位空白的情况下，甚至可以在光滑弯曲的三维表面上书写测量网格。采用“轮廓切割”方法，使网格尺寸最小化，减少激光加工时间，从而实现微米尺寸网格的快速、灵活和无掩模加工。这将扩展这种传感器类型的可能应用范围（例如，包括在非常狭窄的空间中使用）。本文将介绍一种适合于用超短脉冲激光在聚酰亚胺基板上温和、选择性烧蚀镍铬的工艺。在激光辐照强度为φ = 0.43 J/cm(2)，扫描速度为2000 mm/s时，获得了最佳效果。此外，将研究传感器层的热稳定性，并在弯曲试验中对传感器进行表征。
A new concept for foil based micro strain gages (mu SG) with sensor elements smaller than 1 mm(2) and made possible by a laser contouring process will be presented. In contrast to photolithographic structuring, strain gages structured by laser ablation can be precisely tailored at their measuring destination after the strain sensor blank has been applied. Sensors for measuring very spatially confined elongations in particular, require a precisely positioned and small grid. Accurate mechanical positioning of the measuring grid at the micrometer scale can be challenging due to the much larger, bulky, foil substrate. In cases where a blank is positioned prior to grid patterning by laser ablation, it is even possible to write the measuring grid on smoothly curved, three-dimensional surfaces. A "contour cutting" method is used to minimize grid dimensions and reduce laser processing time, which enables the realization of micrometer-sized grids in a fast, flexible and maskless process. This will extend the range of possible applications for this sensor type (e.g. to include use in very confined spaces). This paper will present the development of a suitable process for the gentle, selective ablation of nickel-chromium on polyimide substrates by means of ultrashort-pulse lasers. The best results were achieved at a laser fluence of phi = 0,43 J/cm(2) and a scan speed of 2000 mm/s. Furthermore, the thermal stability of the sensor layer will be investigated and sensors will be characterized in bending tests.