When the robotic arm lifts a freshly welded door panel from the welding cell and moves it toward the final‑assembly line, the locking disc with pin is pressed into the door‑latch housing to provide a precise, repeatable reference point. The pin‑mounted disc engages a matching groove in the latch mechanism, holding the panel in exact alignment while the surrounding bolts are tightened. This single component eliminates any lateral play that could cause mis‑fit of the latch, ensuring the door closes smoothly and the seal remains uninterrupted. Its compact design allows it to be installed by the same robot that positions the panel, keeping cycle time low and reducing the need for additional fixturing. Beyond door assembly, the same locking disc is often used in chassis sub‑assembly stations where it secures engine‑mount brackets to the frame, guaranteeing that torque is applied to the correct datum before the bracket is permanently welded. In both cases the part acts as a simple yet reliable geometric lock, enabling high‑volume production lines to maintain tight tolerances without manual intervention.