Adhesive Curing by Induction

Posted on 9/20/2018 9:23:26 AM By Deb Bhattacharjee
  

Stringent productivity improvement requirements in many industrial, appliance and automotive production demand very short adhesive curing times without impacting strength and performance attributes. Unlike conventional heating of the whole assembly by using convection ovens, the application of electromagnetic induction enables rapid processes and curing of adhesives, even when it is applied in difficult to access areas.  Induction cure delivers heat precisely where it is required in the adhesive, thereby minimizing the possible damage on adjoining area.

During induction curing, the energy is introduced to the substrate by means of alternating electromagnetic fields in the kHz frequency range. In the case of conductive metallic parts, the workpieces will heat very quickly, as will the bond line. Compared to traditional heating, no time is needed for the heat transfer, so the adhesive can be cured within several seconds to a few minutes. When working with non-conductive substrates, like ceramics, polymers or composites, adhesives are formulated withelectrically conductive suceptors e.g., graphite, which then transfers the heat to the non-conducting material.

The benefits would include joining of metallic partsand of metallic parts with non-metallic substrates, potting and bonding of non-metal components (e.g., plastics, glass, and ceramics) without any heating. Specific heating of the adhesive can also be realized by customized formulation of the polymer. Obviously the adhesive formulation and optimum temperature profile for induction curing process (frequency, power) have to be determined for substrate and equipment geometry.

The induction heating equipment has also been used to pre-cure adhesives in hemmed edge of many closure panels i.e. doors, hoods, and trunk panels tailgates.The versatility of current induction heating equipment creates new opportunities of bonding carbon fiber reinforced composites/metal and carbon-fiber/carbon-fiber joints by achieving rapid substrate heating via induction-induced eddy currents.

References

Fraunhofer Institute for Manufacturing Technology and Advanced Materials https://www.ifam.fraunhofer.de

“Induction Curing of a Phase-Toughened Adhesive”, Wetzel, E. D., Sands, J. M., and Yungwirth, C. J., Army ReseArch Laboratory,ARL-TR-2999, June 2003

EFD Induction: http://www.efd-induction.com/

“Adhesion,” by Maurer, A., Lammel, C., Adhesives & Sealants, 11 (1), 2014, pp. 26-29. 

Permabond Engineering Adhesives, www.permabond.com



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