%0 Journal Article %1 Holder_2021 %A Holder, Daniel %A Buser, Matthias %A Boley, Steffen %A Weber, Rudolf %A Graf, Thomas %D 2021 %I Elsevier BV %J Materials & Design %K CFRP OCT ablation myown peer %P 109567 %R 10.1016/j.matdes.2021.109567 %T Image processing based detection of the fibre orientation during depth-controlled laser ablation of CFRP monitored by optical coherence tomography %U https://doi.org/10.1016%2Fj.matdes.2021.109567 %V 203 %X Layer-accurate and precisely stepped removal of damaged areas is required for the repairing process of parts made of carbon fibre-reinforced plastic (CFRP) to obtain a high bonding strength of the repair plies in the rebuilding process. Conventional techniques are characterized by a high degree of manual labour and mechanical load of the processed part. Here, a novel laser-based and controlled approach for automated and layer-accurate removal of damaged areas is presented. In-line depth measurements by optical coherence tomography during nanosecond laser ablation enable depth-controlled homogeneous material removal with minimum damage <10 µm and low surface roughness in the range of 7 µm to 13 µm. The processed layer must be detected for an unknown or varying layer thickness to stop the ablation process at the interface between two layers and not somewhere within one ply. The image processing-based determination of the fibre orientation from the depth measurements allow for a reliable online detection of the processed layer with a maximum error of 4° and root mean square error of 1.1°. As a result, layer-accurate damage removal is demonstrated for a complex repairing geometry. The suitability of the automated laser-based approach as preparation for repairing is proven by cross-sections and scanning-electron-microscopy.

@article{Holder_2021, abstract = {Layer-accurate and precisely stepped removal of damaged areas is required for the repairing process of parts made of carbon fibre-reinforced plastic (CFRP) to obtain a high bonding strength of the repair plies in the rebuilding process. Conventional techniques are characterized by a high degree of manual labour and mechanical load of the processed part. Here, a novel laser-based and controlled approach for automated and layer-accurate removal of damaged areas is presented. In-line depth measurements by optical coherence tomography during nanosecond laser ablation enable depth-controlled homogeneous material removal with minimum damage <10 µm and low surface roughness in the range of 7 µm to 13 µm. The processed layer must be detected for an unknown or varying layer thickness to stop the ablation process at the interface between two layers and not somewhere within one ply. The image processing-based determination of the fibre orientation from the depth measurements allow for a reliable online detection of the processed layer with a maximum error of 4° and root mean square error of 1.1°. As a result, layer-accurate damage removal is demonstrated for a complex repairing geometry. The suitability of the automated laser-based approach as preparation for repairing is proven by cross-sections and scanning-electron-microscopy. }, added-at = {2021-02-27T11:54:51.000+0100}, author = {Holder, Daniel and Buser, Matthias and Boley, Steffen and Weber, Rudolf and Graf, Thomas}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2ef8dc07b71be0b03a7e9ddc390b0442b/danielholder}, doi = {10.1016/j.matdes.2021.109567}, interhash = {1422afdbf08ebd368ab4b00474a8b983}, intrahash = {ef8dc07b71be0b03a7e9ddc390b0442b}, journal = {Materials {\&} Design}, keywords = {CFRP OCT ablation myown peer}, month = may, pages = 109567, publisher = {Elsevier {BV}}, timestamp = {2021-02-27T10:56:27.000+0100}, title = {Image processing based detection of the fibre orientation during depth-controlled laser ablation of {CFRP} monitored by optical coherence tomography}, url = {https://doi.org/10.1016%2Fj.matdes.2021.109567}, volume = 203, year = 2021 }