The process parameters during spinning determine the changes in fiber formation, and significantly influence spinnability, the structure and properties of the wound yarn, as well as the characteristics of the finished filament.
1. Melt Temperature
Also referred to as spinning temperature, it is determined by the screw extruder, the spinning manifold, and the pack pressure. Proper control of the melt temperature ensures good spinnability and results in excellent physical and mechanical properties of the finished filament. When the intrinsic viscosity of the chip is between 0.64 and 0.66, the melt temperature is preferably controlled in the range of 285–290 °C.
2. Screw Extrusion Pressure
The melt pressure at the outlet of the screw extruder is called screw extrusion pressure, which is measured, displayed, and controlled by a pressure sensor. The screw extrusion pressure is used to overcome the resistance of the melt in the pipelines, mixers, and other equipment, ensuring a certain melt pressure at the inlet of the metering pump.
3. Pump Delivery Rate
The weight of melt delivered by the metering pump per unit time is the pump delivery rate. The pump delivery rate is adjusted by the pump speed. Generally, the allowable speed of the metering pump is 15–40 r/min, and 20–30 r/min is recommended.
4. Pack Pressure
Pack pressure is used to overcome the resistance encountered by the melt as it passes through the filter media and spinneret orifices, and is closely related to the uniformity of fiber quality. During high-pressure spinning, when the pack pressure is in the range of 98×10⁵–245×10⁵ Pa, the quality of the wound yarn is relatively good.
5. Cooling Air Temperature, Humidity, and Velocity
For filament spinning, cross-flow air quenching is generally adopted, which mainly involves three parameters: temperature, humidity, and air velocity, in addition to the air velocity distribution across the quenching screen. The cooling air temperature is controlled between 20 and 30 °C. If the spinning speed increases, the air temperature should be appropriately lowered to accelerate cooling. A certain humidity in the cooling air prevents static electricity caused by friction between the filament and dry air in the duct, reducing filament vibration. Humid air also helps maintain a constant temperature in the spinning room, facilitates heat transfer, and enhances filament cooling. Relative humidity in the range of 65–80 % is acceptable. Air velocity has a significant effect on the pre-orientation and draw ratio of the wound yarn. As air velocity increases, the birefringence of the wound yarn decreases and the cold draw ratio increases.
6. Winding Speed
Winding speed is an important factor affecting the degree of pre-orientation of the wound yarn. The higher the winding speed, the higher the degree of pre-orientation and the lower the post-draw ratio.
7. Reciprocating Frequency of the Traverse Guide
The reciprocating frequency of the traverse guide determines the winding angle of the package and also affects the winding tension; it is critical for achieving good package formation. To prevent poor package formation due to ribbon winding, the reciprocating frequency of the traverse guide should be varied periodically. The range of variation is called the amplitude, and the time interval is called the period. The amplitude is generally ±15–25 r/min, and the period is generally 15–25 s.
8. Oil Roller Speed and Oil Concentration
The amount of finish applied to the wound yarn directly determines the finish content of the finished multifilament. The higher the oil concentration and the faster the oil roller speed, the higher the finish uptake on the wound yarn.
Futai Machinery Co., Ltd. has many years of industry experience in the field of spinning and texturing machine accessories. We can supply Metal Sand, Leaf Disc Filters, Candle Filters, Spin Pack Filters, spinnerets, Spin Pack Body, metering pumps, filtration System, Texturing Machine Spare Parts, PU Discs, Interlacing Jets, Suction Guns, Spindles, Ceramic Guides, and various auxiliary equipment.
Post time: Apr-27-2026