On the evaluating surface quality of Nomex honeycomb composites by using surface roughness

Nomex Honeycomb Composites (NHCs) are widely utilized in various industries. However, traditional surface quality evaluation methods (particularly surface roughness) are deemed inadequate for NHCs owing to their lattice-like structure. To overcome this limitation, new criteria such as flatness defects have been introduced. Nonetheless, there remains a notable gap in systematic research investigating the underlying reasons for the inadequacy of surface roughness measurements for NHCs. Furthermore, certain scholars have been employing surface roughness as a metric for NHC surface quality without fully grasping its applicability, leading to widespread confusion. This study aims to clarify this issue by conducting a comprehensive and meticulous investigation, thereby establishing a link between traditional and cutting-edge evaluation methods. Initially, the robustness of surface roughness was investigated. It was found that during random sampling, provided the number of sampled points is sufficient, the calculated surface roughness can effectively reflect the overall topographical characteristics. This finding indicates that surface roughness can be reliably determined, even with the discontinuous lattice-like structure of NHCs. Further research has revealed that there is a strong linear relationship between flatness defects and surface roughness even at different measurement scales, indicating that surface roughness can directly characterize the surface morphology of NHCs. Additionally, the actual surface measurement experimental results show that, provided the resolution scale is met, surface roughness can effectively evaluate the surface machining quality of NHCs. Furthermore, experimental comparisons have shown that surface roughness can more comprehensively reflect the overall morphology of the surface, providing a more robust quality evaluation.