Self-tapping screws for plastic, like the name suggests, form or tap its threads while screwing into plastic, and you can install them into pre-drill or mold pilot holes. The self-tapping screw fastener manufacturer offers an economical method of linking two plastics or plastic to metal and permits easy disassembly and re-assembly.
Self-tapping screws fastener for plastic
They are commonly erroneous to self-drilling screws, but self-drilling screws have a drilling tip at the end, and you can use it without a pilot hole.
Thread profile angle is also called a flank angle of self-tapping screws, which are smaller. It reduces the internal radial stresses formed during the plastic’s removal and deformation. Moreover, the thread engagement diametrically is more significant since the root diameter is smaller than the standard fasteners, which upsurges the holding power on soft plastic compared to metal.
Types of self-tapping screws
The manufacture usually divides them into two groups, including thread forming and thread cutting. The selection of screw-type depends on their application obligation, material type, and properties. There are variously trademarked and patent designs from several companies like Stanley, EPOK, TR fasteners, etc. There are many thread profile angles (30-45-48 degrees) available in the market.
Thread-forming fasteners do not have a sharp tip and may need a pilot hole. They create threads by deforming and displacing the plastic item, which may flow around the screw threads. Therefore, the overlapping quantity and thread profile angle are vital.
As you deform the material rather than removing it, significant internal stresses are led. Therefore, you can use these elf-tapping screws in soft plastics with flexural modulus below 200,000 psi, i.e.,1380MPa.
The self-tapping screw fastener manufacturer, sometimes referred to as thread tapping and has a sharp cutting edge, eliminating plastic material since you screw it into the pilot hole. These create reduced internal stresses than thread-forming screws, making it appropriate for stiffer plastic material with flexural modulus between 200,000 psi – 1,000,000 psi.
It is significant to make the hole the right size and more profound than the screw engagement length, so the removed plastic material has space to move. These offer high thread engagement, high clamp loads & reduced stress for fiber or glass-filled plastics. The most significant disadvantage of the thread-cutting screw is thread stripping during disassembly.
Flexural modulus of plastics
Flexural or bending modulus measures the plastic’s toughness during the initial step of the bending process and figured as the ratio of stress to strain in flexural deformation. In simple words, plastics tendency to repel bending.
You can use plastics’ flexural modulus as an indicator of how different types of plastics respond when you use self-tapping fasteners. Low flexural modulus means, that more material flow and permit the formation of threads.
Benefits of using self-tapping screws for plastic
- Easily disassembled
- Good impact and vibration resistance
- Self-tapping screws for plastic connection is reliable if used properly
- They are cheap than other means of joining
- It does not require pre-molded threads
- No medicinal time or settling time as the total strength is attained immediately
- No special tool necessary