Laser-based hot-melt bonding of CFRP and GFRP - A novel joining technology for multi-material-design

Abstract

Due to increasing ecological awareness lightweight design became a focus in the past few years. Fiber reinforced plastics (FRP) with thermosetting matrix are commonly used for lightweight constructions. Their strength-to-weight ratio is significantly higher in comparison to metallic construction materials. However in many cases product-specific requirements can be only achieved by multi-material-systems. Therefore it is necessary to reach an integration of different materials by means of suitable joining technologies. According to the current state of the art joining of thermosetting composite to thermoplastic is limited by available joining techniques. A solution for this problem offers laser-based hot-melt bonding. This paper presents experimental results of joining carbon fiber reinforced plastics (CFRP) as well as glass fiber reinforced plastics (GFRP) to thermoplastics by means of laser-based hot-melt bonding. Thereby the influence of surface treatment and used thermoplastic on the joint connection is investigated. The specimens are characterized by microscopy and tensile shear tests. Additionally climate tests are performed to analyze the long-term durability of the joint connections. Besides a thermal simulation of the joining process is developed that predicts temperature fields during the joining process. Finally a comparison between laser-based hot-melt bonding and conventional adhesive bonding is given.Due to increasing ecological awareness lightweight design became a focus in the past few years. Fiber reinforced plastics (FRP) with thermosetting matrix are commonly used for lightweight constructions. Their strength-to-weight ratio is significantly higher in comparison to metallic construction materials. However in many cases product-specific requirements can be only achieved by multi-material-systems. Therefore it is necessary to reach an integration of different materials by means of suitable joining technologies. According to the current state of the art joining of thermosetting composite to thermoplastic is limited by available joining techniques. A solution for this problem offers laser-based hot-melt bonding. This paper presents experimental results of joining carbon fiber reinforced plastics (CFRP) as well as glass fiber reinforced plastics (GFRP) to thermoplastics by means of laser-based hot-melt bonding. Thereby the influence of surface treatment and used thermoplastic on the joint connection i...