Jürgen Hierold: The flowform screw is positioned onto the aluminium or steel sheet, which has not been pre-drilled, and the screwdriving process begins. The screw - applied with a high down-force and also rotating at a very high speed - develops a high level of frictional heat, the material begins to flow and a kind of crater forms. In the next step the tip of the screw penetrates the material compound, thus forming a through-funnel. Enough material forms through this funnel shape to allow several thread turns to be applied. This produces a machine thread which can also accept a completely “normal” screw in the event that a repair is required later on. Once the thread has been formed, the screw is tightened to preliminary torque values for the head setting, and the fastening is then tightened to the pre-configured torque and angle parameters.