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Cold laser ablation as a remediation strategy for contaminated CFRP surfaces


Title: Cold laser ablation as a remediation strategy for contaminated CFRP surfaces

Authors: Joann Hilman, R. Giles Dillingham, Rose Roberts

DOI: 10.33599/nasampe/c.23.0050

Abstract: Undetected surface contamination is a major issue affecting reliable bonding or coating of carbon fiber reinforced polymers (CFRP). The most common remediation method for CFRPs is manual solvent wiping + abrasion. Abrasion is time consuming, difficult to control, physically damaging to the surface plies, and subject to operator-to-operator variability. This has led to the search for faster and more controllable remediation techniques. Laser ablation has gained interest as an automated process with precise parameter control. However, traditional 1064nm nanosecond lasers can cause thermal damage to the resin and carbon fiber, making these lasers nonideal for remediation of CFRP surfaces. Lasers that utilize cold ablation, such as UV and femtosecond lasers, cause less thermal damage and result in more controllable surfaces. This work evaluates and compares two laser systems, a femtosecond laser at 1030nm and a nanosecond laser at 355nm, as potential remediation technology for contaminated CFRP surfaces. Epoxy resin based CFRP samples were protected by peel ply prior to testing. A silicone-based mold release agent diluted in xylene and spun coated onto CFRP surfaces was selected as a model contaminant. Changes to the condition of the CFRP surfaces were tracked in real time using water contact angle. Elemental analysis and surface morphology were studied by x-ray photoelectron spectroscopy and scanning electron microscopy respectively. Mode one fracture toughness was investigated using double cantilever beam tests. Both laser systems were able to effectively remove silicone contamination from the surfaces, however, the amount of contamination removal and amount of carbon fiber exposure were related to the individual ablation process. Mode I adhesive test specimens showed interlaminar failure for the UV laser ablated samples and mixed failure in the adhesive as well as within the resin cap for the femtosecond laser. Both laser systems are a viable method for contamination remediation of CFRP surfaces.

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Conference: CAMX 2023

Publication Date: 2023/10/30

SKU: TP23-0000000050

Pages: 13

Price: $26.00

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