Thermal Curing of Adhesive Joints Enabled by Precision Heating Multi-Material Additive Manufacturing

This study explores the development of adhesive joints incorporating embedded resistive heating elements, fabricated using Multi-Material Additive Manufacturing. By embedding conductive circuits within the adherends, localized heating enables controlled curing of the adhesive, optimizing its mechanical properties according to the specific application. This study focused on modifying the stiffness of the adhesive in order to reduce edge effects in the joints and allow for better load distribution. The adherends were made of PLA, the resistive heating elements were fabricated using carbon black-filled conductive PLA, and an epoxy resin served as the adhesive. Thermal and mechanical characterizations were conducted, evaluating the effects of different curing temperatures on joint strength. The tensile strength for joints cured at 120 °C exhibited a 58% increase in maximum breaking force and a 144% increase in elongation at break compared to the joints cured at room temperature. These findings highlight the potential of AM-integrated resistive heating for precise adhesive curing, enabling the local tailoring of the adhesive stiffness in the overlap volume.