Uneven Oil Agent

The spinning oil agent or finishing agent adheres unevenly on the fiber, locally too much or too little, and the yarn bundle hand feel is inconsistent. Uneven oil agent directly affects the spinnability of the fiber — where oiling is insufficient, the friction is large and breakage is easy; where oiling is excessive, the yarn sticks together and is not easy to separate into bundles. Uneven oil agent distribution also causes inconsistent tension of the yarn bundle during drawing, leading to denier fluctuation and uneven drawing.

1. Mold/tooling factor: the oiling nozzle or oil roller is damaged, skewed or clogged. 2. Material/formulation factor: unstable oil agent concentration or liquid level. 3. Material/formulation factor: unsuitable temperature of the oil agent circulation tank causes viscosity changes. 4. Comprehensive factor: unstable position of the fiber before entering the oil nozzle. 5. Cooling air field factor: the temperature, wind speed and uniformity of the side-blowing air or ring-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 thickness of individual filaments in the same bundle, and low wind speed leads to filament sticking and filament breakage; the air field parameters need to be precisely controlled.

1. Process parameter optimization and adjustment: regularly check and maintain the oiling components. 2. Mold/tooling improvement and maintenance: stabilize the oil agent concentration and liquid level. 3. Equipment inspection and system maintenance: oil agent temperature control. 4. Material/formulation optimization: yarn guides that guide the yarn bundle into position before entering the oil nozzle. 6. 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 the 5Why analysis method to trace the root cause, and solidify the 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.

This problem is a typical manifestation of uneven oil agent in melt spinning. The core of the solution lies in the precise stability of the spinning temperature, the high-precision control of metering supply, and the optimized maintenance of the spinneret/cooling air field. It is recommended to start from chip quality and spinning parameters, and gradually troubleshoot to the equipment and component level.