With direct screwing the fasteners generate a thread when screwed in without cutting.
The principle of non-cutting forming used here produces a thread with high load-bearing capacity due to the uninterrupted grain flow and strain-hardening of the material. Additional thread locking adhesives (e.g. to DIN 267-27/28) are therefore superfluous. The generated thread is a metric ISO thread which is compatible with standard parts. Furthermore, the threads formed in this way are backlash-free and self-locking. Thread forming screws can be used in all ductile, i.e. plastically deformable materials.
In the automotive industry, direct screwing systems are often used to connect components. Direct screwing offers cost advantages through the elimination of thread cutting and direct use in cast, drilled or punched holes. In addition to this, through the forming process of the thread, no interfering chips are created.
For various materials, such as plastics and metals, different screws are usually selected, which meet the respective requirements. At the same time, however, the topic of standardization is gaining importance. A hybrid construction with various materials, such as aluminum, magnesium and zinc die-cast as well as thermoplastics and thermosetting plastics, is becoming increasingly common. With direct screwing systems, which can be used with various materials, existing screws can be replaced and thus the diversity of parts reduced
Coolant and lubricant circuits are required for ensuring component function in a variety of different areas and applications in the automotive industry, from gearboxes and pumps to engine blocks. These have to be closed and sealed.
Usually, screw plugs (with or without under-head seal) or expander solutions are used for sealing holes. In contrast to screw plugs, expanders cannot be removed without being destroyed.
In addition, these sealing elements close off the hole, but require complex preparation of the bore hole.
For example, the process of drilling, countersinking, milling the head contact surface and cleaning the thread when using screw plugs is very time consuming and expensive.
The increasing complexity of components in the automotive industry is also increasing the demands placed on fasteners. They should not only connect, but also solve complex problems in the application.
Application problems can arise, for example, due to processing-related residues in the counterpart. These residues jeopardize the secure connection between the screw and counterpart. Fasteners with function integration can overcome such challenges due to their special additionally integrated functions.