Importance of Non-Contact Profilometry for Composite Materials

It is crucial defects are minimized so composite materials are as strong as possible in reinforcement applications. As an anisotropic material, it is critical weave direction is consistent to maintain high performance predictability. Composite materials have one of the highest strength to weight ratios making it stronger than steel in some cases. It is important to limit exposed surface area in composites to minimize chemical vulnerability and thermal expansion effects. Profilometry surface inspection is critical to quality control production of composites to ensure strong performance over a long service time.

Nanovea’s 3D Non-Contact Profilometer is unlike other surface measurement techniques such as touch probes or interferometry. Our profilometers use axial chromatism to measure nearly any surface and open staging allows for samples of any size with no preparation needed. Nano through macro measurements are obtained during surface profile measurement with zero influence from sample reflectivity or absorption. Our profilometers easily measure any material: transparent, opaque, specular, diffusive, polished, and rough with the advanced ability to measure high surface angles with no software manipulation. The Non-Contact Profilometer technique provides the ideal and user-friendly capability to maximize composite material surface studies; along with the benefits of combined 2D & 3D capability.

Measurement Objective

The Nanovea HS2000L Profilometer used in this application measured the surface of two weaves of carbon fiber composites. Surface roughness, weave length, isotropy, fractal analysis, and other surface parameters are used to characterize the composites. The area measured was randomly selected and assumed large enough that property values can be compared using Nanovea’s powerful surface analysis software.

Results and Discussion

Surface Analysis

 

 

 

Isotropy shows directionality of the weave to determine expected property values. Our study shows how the bidirectional composite is ~60% isotropic as expected. Meanwhile, the unidirectional composite is ~13% isotropic due to the strong single fiber path direction fiber.

Weave size determines the consistency of packing and width of fibers used in the composite. Our study shows how easily we can measure weave size down to micron accuracy to ensure quality parts.

Texture analysis of the dominant wavelength suggests strand size for both composites are 4.27 microns thick. Fractal dimension analysis of the fiber surface determines smoothness to find how easily fibers will set in a matrix. The fractal dimension of the unidirectional fiber is higher than the bidirectional fiber which may affect the processing of composites.

Conclusion

In this application, we have shown the Nanovea HS2000L Non-Contact Profilometer precisely characterizes the fibrous surface of composite materials. We distinguished differences between weave types of carbon fiber with height parameters, isotropy, texture analysis, and distance measurements along with much more.

Our profilometer surface measurements precisely and quickly mitigate composite damage which decreases defects in parts, maximizing composite material capability. Nanovea’s 3D profilometer speed ranges from <1mm/s to 500mm/s for suitability in research applications to the needs of high-speed inspection. The Nanovea profilometer is the solution
to any composite measurement need.