SELECTION OF ADHESIVE SYSTEM FOR RADIOFREQUENCY HEATING OF STRUCTURALSHEET MOLDING COMPOUND COMPONENTS

A series of laboratory tests and computer simulations of adhesive curi ng enhanced by radio-frequency heating indicated that not all adhesive systems can be effectively used for RF-based curing because of the da nger of thermal runaway. Our investigation of the process mechanism al so resulted in several other findings that could lead to further impro vement of the processing cycle. Both experimental and theoretical resu lts indicated a high sensitivity of the adhesive exothermal reaction k inetics to the thickness of the bond line, which varies with changes o f the thickness of the processed sheet molding compound (SMC) componen ts. Thus, regardless of the type of adhesive system employed, tighter dimensional tolerance would ensure better quality of the bond. Finally , we proved that the initial surface temperature of the SMC members su bstantially affects the process effectiveness and joint quality, and s hould be strictly monitored.