Spinneret Capillary Rupture of Ultra-fine Fibers (Monofilament Fineness <0.3 dtex)

The yarn output of one or several holes of the spinneret decreases or is completely blocked, with no yarn extruded from the corresponding hole position or only extremely fine yarn extruded. Spinneret blockage reduces the number of spinning positions and decreases output; the holes around the blocked hole fluctuate in yarn output due to flow redistribution, affecting the uniformity of the entire tow. When blockage is severe, the machine must be stopped to replace and clean the spinneret, and each shutdown loses several hours of production and dozens of kilograms of waste yarn.

1. Spinning temperature factors: The spinning temperature determines melt viscosity and rheological behavior, directly affecting the spinnability, fineness uniformity, and surface quality of the fiber. Excessively high temperature leads to degradation yellowing and filament breakage; excessively low temperature leads to poor plasticization and increased extrusion pressure; it needs to be precisely set according to the chip IV value and stably controlled. 2. Cooling air field factors: The temperature, wind speed, and uniformity of side-blowing or circular-blowing air determine the solidification and forming quality of the fiber—too fast cooling leads to rough surface and increased internal stress, uneven cooling leads to inconsistent fineness among filaments in the same bundle, and low wind speed leads to filament sticking and filament breakage; air field parameters need to be precisely controlled.

1. Process parameter optimization and adjustment: Use fatigue-resistant materials of special alloy raw materials (such as Hastelloy) to make the plate. 2. Systematic troubleshooting method: Troubleshooting of spinning problems follows the order of "chips → temperature → metering → spinneret → cooling air". First check the chip dryness and IV value, then verify the temperature of each section of the spinning manifold and piping, then verify the metering pump accuracy and pressure stability, further check the spinneret cleanliness and hole shape condition, and finally adjust the cooling air field parameters to make the wind speed and temperature evenly distributed. 3. Preventive management: Establish standardized process parameter cards and quality control limits for each mold/product, and regularly conduct process capability index (CPK) evaluations. For recurring problems, use fishbone diagrams or 5Why analysis to trace the root cause, and solidify countermeasures as PFMEA control points. Establish a regular equipment maintenance system and implement life management for key tooling such as dies/spinnerets/calender rolls/coating heads.

The essence of spinneret blockage is that impurity particles or degraded gel in the melt block the tiny spinneret hole entrances. The core of the solution is "cleanliness + filtration + regular cleaning": strengthen chip purity control to reduce impurity sources, use pre-filters (sintered metal filters, sand layers) to intercept gel particles, and regularly clean the spinneret with the triethylene glycol ultrasonic method.