Deformation and Anchoring of AA 2024-T3 rivets within thin printed circuit boards

This work evaluates the viability of applying Friction Riveting as an alternative for the assembly of components on printed circuit boards (PCBs). The popular press-fit technology for assembling components on PCBs consists of a pin inserted tightly into a relatively smaller hole, resulting in good electrical and mechanical properties. However, some limitations are highlighted, such as numerous processing steps and the need for predrilled holes. Friction Riveting is based on mechanical fastening and friction welding principles, where polymeric components are joined with metallic rivets through frictional heating and pressure. The main benefits of using Friction Riveting in PCBs compared with fit-press are (i) a reduced number of processing steps and (ii) shorter joining cycles, because there is no pre-drilling involved with fasteners anchored within the PCB in a single step. The joints were manufactured using 5 mm diameter AA-2024-T3 rivets and 1.5 mm thick glass-fiber-reinforced epoxy laminates (FR4-PCB). It is shown for the first time that it is possible to deform metallic rivets within thin composite plates at a reduced diameterto-thickness ratio. The feasibility study followed a one-factor-a-time approach for parameter screening and optical microscopy assessed joint formation of the deformed rivets inside the laminates through volumetric ratio (VR). The joints present significant deformation (VR=0.5) at the tip of the rivet inserted into overlapped PCBs plates, with thicknesses below 3.0 mm, which is considered the lowest achieved so far with Friction Riveting.