Nanosecond laser debonding of strong adhesives

The goal of this paper is to determine whether laser-induced surface melting can generate adhesive debonding. Commercial cyanoacrylate and acrylic adhesives are used to attach an aluminum (Al) cylinder to a transparent polymethyl(methacrylate) (PMMA) plate, and then a variable force is applied to create an axially loaded butt joint. High energy nanosecond laser pulses at 1064 and 532 nm are directed through the transparent PMMA to be absorbed at the Al surface, causing transient localized heating that leads to joint failure. The dependence of this debonding on both laser fluence (energy per area) and applied force are investigated. Single shot debonding occurs at fluences on the order of 0.47 J/cm2 for 1064 nm and 0.29 J/cm2 for 532 nm pulses with an applied pressure of 0.22 MPa. Characterization of the Al surface before and after laser impact confirms that the debonding arises from surface melting and causes only slight changes to the Al surface. A simple model of the debonding process is developed to explain the dependence of the debonding on the applied load. Single laser pulses can generate instantaneous, relatively clean separation of bonded joints, suggesting that laser debonding may be a promising strategy to initiate deadhesion.