The principle is to soften the plate to be connected by the high-speed rotation of the screw, and squeeze and screw into the plate to be connected under a large axial pressure, and finally form a threaded connection between the plate and the screw, while the parent material at the center hole is squeezed out and forms an annular sleeve at the bottom of the lower plate. According to the data, FDS was invented in 1990 and was first used for the connection of car body frames in 1996. Since the clamping was mainly done by hand-held clamps at that time, the time and accuracy of the installation process were difficult to control, which limited the use of this process. In the 1990s, Weber developed a screw drive system for EJOT, which realized the automated production of the FDS process and was first used in the connection of the rear wheel cover of Audi A4 in 2000. At present, the main domestic screw suppliers are Arnold and EJOT.

Usage scenarios

Because a small part of the sheet metal will bulge upward during the plastic deformation process, the concave design of the head flange is to leave space for the bulging material to prevent a gap between the flange surface and the sheet metal after installation.

Surface treatment method

FDS screws are a perfect combination of the three functions of hot melt drill, extrusion tap and bolt tightening.

FDS installation process

1. Heating: The flow drill screw contacts the surface of the plate and rotates at high speed to generate a higher temperature locally on the plate

2. Extrusion hole: The plate undergoes plastic deformation along with the shape of the screw head under the high speed and axial pressure of the flow drill screw

3. Through hole: The flow drill screw drills a cylindrical through hole on the plate

4. Tapping: The plate is drilled by the flow drill screw, and the speed and pressure are reduced, so that the flow drill screw can self-tap the thread in the hole

5. Threading: Normal screw tightening process

6. Tightening: The plate cools and fits tightly with the flow drill screw to form a highly sealed connection