Spinnerets are also called spinning caps. The function of spinneret is to change the melt or solution of high polymer with viscous flow state into a small stream with specific section through micropores, and then solidify through solidification medium such as air or solidification bath to form a filament.

According to the types and specifications of fiber, there are different specifications, shapes, holes, materials and so on. Spinnerets work at high temperatures and pressures. Pressure resistance, corrosion resistance and adequate mechanical strength are required.