A comprehensive experimental study of the potential use of 3D printable thermoplastic polymers as structural adhesives

Abstract This paper deals with the potential use of 3D printable thermoplastic polymers as structural adhesives. Acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and thermoplastic polyurethane (TPU) were used as thermoplastic adhesive. The assembly of the steel adherends with thermoplastic adhesives was conducted by using induction heating (IH). Thick adherend shear test (TAST) was performed to evaluate the shear load capacity of adhesives. Tensile and three point-bending (3P-B) tests of the single lap joint (SLJ) were carried out to evaluate the performance of adhesives under in-plane and transverse loadings. According to experimental results, PETG showed the best performance among the other adhesives for the shear and tensile loadings. The maximum shear load of PETG is about 102% higher than that of TPU, which has the lowest shear load capacity. A comparison of TAST results displayed little difference in the maximum shear loads between the ABS and PLA adhesives. The highest tensile failure load was obtained for PETG and the weakest one for ABS. In the case of ABS and PLA adhesives, the failure loads were reduced by 42.73% and 11.28%, respectively, compared to the joint with TPU adhesive. Moreover, printable thermoplastic adhesives showed comparable joint strength to commercial structural adhesives under tensile loading. In the case of transverse loading, it was revealed that TPU is the best choice. According to the 3P-B tests, the highest bending load (1338N) was obtained for the TPU adhesive, and the lowest bending load (267N) was obtained for the ABS adhesive.