Self-tapping screw is a kind of threaded fastener, which drills the female thread in the pre-drilled hole of metal or nonmetal materials.
Round head: It is the most commonly used head type in the past.
Flat head: a new design that can replace round head and mushroom head. The head has a large diameter, and the periphery of the head is connected with a high-profile edge, which makes it play a driving role in high-strength torque.
Hexagon head: This is a standard type in which torque is applied to the hexagonal head. It is characterized by trimming sharp corners to close to the tolerance range. It is suitable for various standard patterns and various thread diameters.
Drive types: slotted, Philips, and pozi .