Metals and plastics have been widely used in several industrial applications such as automobiles, aircrafts and electronic devices. Joining of a metal and a plastic is important and necessary from a fundamental viewpoint of manufacturing. The joining has been performed using adhesion bonds (glues) or mechanical tools such as rivets. However, it has some problems in terms of environment, preserved conditions and mass production. It is thus expected that a noble innovative method should be developed for direct joining of metals and plastics. Therefore, we have newly developed a noble Laser-Assisted Metal and Plastic (LAMP) joining method. The LAMP joining method could produce a strong joint between a Type 304 stainless steel plate and an amorphous polyamide plastic sheet. The tensile shear test samples of 30 mm width and 2 mm thickness possessed the tensile shear loads of over 1,560 N. Moreover, the tensile shear load of 3,390 N was achieved for a wide LAMP joint including sub-millimeter-sized bubbles, which were formed from rapid heating and quenching due to the heat input of a line-beam-shaped diode laser. It was found that the joint strengths depended upon not only the area of a joint part but also bubbles formation and size. The SEM images of the LAMP joints demonstrated that the stainless steel and the polyamide plastic were closely bonded in micro size.
