4. Inserts

Insert fastening is a compromise between bonding and mechanical assembly. It consists of introducing a metal insert into the composite material, which may be the male or female part of a screw connection. If introduced before the resin has hardened and between the fibers, it does not weaken the part in any way. Alternatively, it can be glued in place after the resin has cured, with the addition of a paste adhesive.

Finally, it can be force-fitted into thermoplastic composites using hot or ultrasonic techniques.

In all these cases, it doesn't weaken the parts, it enables very solid assembly of different materials, and it allows disassembly, thanks to the internal thread.

Figure 5 shows an...