Analysis and Optimization of Stick-Slip Behaviour in Metal-Plastic Interfaces for Connected Tail Lamp Assemblies in Electric Vehicles

The seamless and sleek design of connected tail lamps adds a visually striking element to the car's exterior. It aligns with contemporary automotive trends and gives the vehicle a premium and futuristic appearance. Automakers use these lamps as a design signature to establish brand identity. Connected tail lamps improve visibility for drivers behind the vehicle. The assembly of connected tail lamps can pose several challenges, especially due to their complex design and integration requirements. Metal-plastic creak is a common concern in electric vehicles (EVs), often noticeable when driving on uneven roads. This primarily results from stick-slip behaviour at the interface of metal and plastic components, intensified by improper alignment. When the designed geometric dimensioning and tolerancing (GD&T) is not met in real manufacturing conditions, misalignment introduces unintended contact forces, leading to intermittent micro-sliding and frictional energy release, which manifests as an audible creak. The absence of an internal combustion engine in EVs further increases the perceptibility of such noises. This paper explores the influence of mounting fitment on noise generation and investigates the optimization of assembly strategies to minimize stick-slip interactions. Through experimental testing and finite element analysis, we aim to provide insights into mitigating metal-plastic creak by refining tolerances, material pairings, and assembly processes to improve overall perceived quality. This advancement minimizes unwanted noise in the vehicles, creating a quieter and more luxurious driving experience.