H. Dittmar
P. Jäschke
S. Kaierle
L. Overmeyer

A study of the effects of NIR laser radiation on interlaminar fracture toughness of CFRP

11th CIRP Conference on Photonic Technologies (LANE)
07.-10. September
Type: Konferenzbeitrag
This research focusses on the analysis of two near-infrared (NIR) lasers’ characteristics with regard to the resulting interlaminar fracture toughness and the identification of a sweet spot for delamination free laser ablation of CFRP. Earlier studies showed that nanosecond-pulsed UV and MIR lasers are able to ablate CFRP without causing an increased risk for delamination as opposed to NIR lasers. However, NIR lasers are more flexible regarding industrial integration. Therefore, the risk of delamination induced by NIR radiation needs to be minimised. It stems from the CFRP’s optical properties and leads to NIR radiation to be mostly absorbed on the carbon fibres’ surface, indirectly removing the matrix and thus risking delamination below the fibres. Mode I interlaminar fracture toughness (GIc) tests evaluate this risk, using two adhesively bonded CFRP surfaces, where one surface received surface treatment. In this work, experiments with two NIR lasers achieved GIc results that matched or surpassed those of mechanically milled references.