Fabrication of glass to PLA joints with an intermediate aluminum layer by using low-cost industrial nanosecond IR fiber lasers

We present an adhesive free, low-cost and effective solution for joining of thermoplastic additive manufactured parts to glass using an industrial nanosecond IR pulsed fiber laser. We demonstrate the potential of the method by means of laser joints of glass to Polylactic Acid (PLA). The glass to PLA joints are realized via Laser Transmission Welding (LTW) and Laser Direct Welding (LDW) using an intermediate sacrificial thin layer of aluminum. The laser joints are compared with adhesive glass to PLA joints. The mechanical testing involves a thorough strength evaluation by using block shear test method, demonstrating the superior performance of laser-welded joints over conventional adhesive alternatives. The results of these shear tests reveal a remarkable 565 % improvement in shear strength in comparison to the adhesive joints (maximum shear strength of laser bonds: 9.57 MPa). Furthermore, a Weibull statistical analysis is applied to assess the reliability of the joints, disclosing a very high survival probability of the samples under a loading of 4.5 MPa as well as a sigma 0 (stress for which the 1/e (37 %) of the samples survive) of 8.15 MPa.