Influence of Laser Texturing on Mechanical Performances of CFRP Single Lap Bonded Joint

Nowadays polymer composites have found increasing use especially in those areas where high mechanical performance is required with the lowest possible weight. For example, often the parts have complex geometries difficult to achieve with a single forming step, so in the industrial field there is the tendency to make more parts of simpler geometry to be assembled later. The use of structural adhesives makes it possible to avoid drilling and the use of bolts, significantly reducing the weight of the joint and the risk to damage the fibers. However, it is often necessary to pretreat the surfaces for manufacturing a reliable joint. For this reason, composite adherends are generally degreased and/or sanded before bonding; this technique presents problems related to the presence of solvents and large volume of dust produced during the process that must be controlled by means of hoods. The use of laser sources for pretreatment can be a valid replacement of these processes. In this work the effectiveness of a pretreatment made with a CO2 laser on CFRP adherends constituting a lap shear bonded joint is investigated. In order to define the treatment parameters for avoiding damages of the laminates, the treated surfaces were analyzed using conoscopic holography and optical analysis. The obtained experimental results show that the joints’ strength is higher than that obtained with degreasing process. Moreover, it represents a sustainable process to prepare the adherend’s surface to bonding, reducing the volume of removed material and limiting dust production.