Recent developments in inductive heating for fast curing of adhesively bonded connections

Fast curing of adhesively bonded connections is increasingly moving into the focus of research and development, as is has been recognised as an effective technique to significantly reduce process times, gain independence from environmental conditions, and enhancing strength, durability and thermo-mechanical properties, amongst others. One of the techniques revived in recent years is induction heating, in which an external electromagnetic field (EMF) results in heating the substrates (if they interact with the EMF [1]), or via particles embedded in the adhesive (if substrates are inert to the EFM[2]). Because of the complexity of the problem, which ultimately involves many different physics (electromagnetism, thermal, curing dynamics, mechanical strength etc.), advances were often achieved stepwise by time intensive trial-and-error procedures. However, industry increasingly requires robust methodologies for planning induction based fast-curing processes, including methods for objective material selection, design of induction coils, determination of appropriated heating regimes, and prediction of times required to achieve predefined levels of strength (from handling to final).This paper presents the current status regarding the design of EM-induction processes for fast-curing adhesively bonded joints, and illustrates them on a selection of examples taken from industrial applications