Locking wheel nuts can only be loosened with a unique key, but the loss of such keys by car owners has led to the development of widely available removal tools.
Now, engineers at Ford and additive manufacturing specialists EOS have created nuts with contours based on the driver’s voice, which - like a fingerprint or iris scan - is a unique form biometric identification.
According to Ford, engineers record the driver’s voice for a minimum of one second and use software to convert that singular soundwave into a physical, printable pattern. The pattern is then turned into a circle and used as the design for the locking nut’s indentation and key.
Once the geometry is known, the nut and key are designed as one piece and 3D-printed in stainless steel. When finished, the nut and key are separated and ready for use after a small amount of finishing.
Ford said the design includes second-level security features that prevent the nut from being cloned or copied. The unevenly spaced ribs inside the nut - and indentations that widen the deeper they go – are claimed to prevent a thief from making a wax imprint of the pattern, as the wax breaks when it is pulled from the nut.
In a statement, Raphael Koch, Ford Advanced Materials and Processes research engineer, said: “It’s one of the worst experiences for a driver, to find their car up on blocks with all four wheels gone. Some alloy wheels can cost thousands to replace, but these unique rim nuts will stop thieves in their tracks. Making wheels more secure and offering more product personalisation are further proof that 3D printing is a game-changer for car production.”