The spinning assembly consists of components such as sealing materials, filter materials, distribution plates, and spinnerets. Its main function is to uniformly mix and filter the melt pumped by the metering pump, and then extrude fine filaments through the spinneret.
The pressure and filtration efficiency of the spinning assembly significantly impact the quality of melt extrusion. The assembly pressure is primarily determined by the structure of the filter layer and the properties of the melt. To ensure smooth melt extrusion, the assembly pressure must be appropriately increased, typically between 20 and 22 MPa.
The main function of the spinning filter media and filter screen is to filter impurities and gels from the melt. Commonly used filter media include sea sand + composite metal mesh and metal sand + metal mesh. Compared to sea sand, metal sand has a longer service life, more uniform physical properties, and ensures consistent melt temperature. Furthermore, the sharp angles of the metal sand can puncture air bubbles, block foreign matter and agglomerated particles, and improve filtration accuracy. This effectively reduces filament breakage and increases production efficiency.
After the melt is extruded through the spinneret, elastic potential energy and hydrostatic energy are released, causing the diameter to expand. This expansion causes changes in the uniformity of the melt, reducing the quality of spinning. The smaller the diameter of the spinneret, the more severe the expansion; the larger the aspect ratio of the spinneret, the weaker the expansion. The aspect ratio of the spinneret for Nylon 66 industrial filament is typically 4:1.
