Annedore Bose-Munde, Arnold Umformtechnik GmbH & Co. KG
When it comes to fastening plastics there are many different influencing factors at play. The challenge is to find a geometry for the screw fastening that balances out any negative effects such as tolerance fluctuations. Moreover, it is important that the fastening solution is optimally adapted to the material’s properties and the type of load it will need to bear.
The strength of the material, the way it is conditioned, the fiber orientation and the type of fiber, the viscoelastic deforming behavior, the component and screw tolerances such as the diameters of the core hole and the screw, and even the precision of the screw-driving system are all factors to bear in mind when implementing direct screw fastenings into plastic materials. And to find out whether a particular screw geometry is suitable for the application in question, it is also important to know the quality characteristics required of the direct screw fastening into the plastic material. The quality characteristics are high overturn torque, low insertion.