The four expensive alloy wheels of a passenger car must not be unintentionally released: Whether the car is parked in the garage, is on high-speed roads, during deceleration, during acceleration, or when using assistance systems such as ABS and ESP.

Thus, there is a self-release torque within the screw connection and a friction torque within the contact surface. In situations where essential parts of the value added chain are outsourced, for example the screw coating process, the screw coater must also ensure and demonstrate the friction.

Screws and nuts ensure safety and that there is no unintentional release by generating a clamping force during assembly, which holds the components together despite the loads exerted on them in use.

TesT also supplies vibration testing machines for the dynamic lateral loading on fasteners and universal testing machines for tensile testing on screws with forces of up to 600kN.Why fastener companies should know about the friction values of their screw connections 30 November 2016 By Julia Kiewitter, marketing,

TesT GmbHA modern car or aeroplane is composed of many thousands of individual parts. In order to prevent this, drive energy must always be supplied. Good practice clearly indicates both screw suppliers and screw users should, for this reason, carry out a friction coefficient determination within the scope of incoming goods inspection.