Wet spinning, as the core process of chemical fiber production, directly determines the fiber quality based on the operational accuracy of its equipment. From raw material preparation to fiber collection, each step requires strict control of key parameters. The following is a detailed explanation of the entire process.
1、 Systematic preparation before commencement of work
Before production, three basic confirmations need to be completed: first, cleanliness testing of the raw liquid system, with no visible particulate matter residue on the inner wall of the storage tank, and a filter pressure difference below the warning threshold; The second is the sealing test of the coagulation bath circulation pipeline, with a focus on inspecting the mechanical seal of the pump body and the flange connection of the pipeline; The third step is to preheat and calibrate the temperature control module to ensure that the temperature difference between each area of the coagulation bath is ≤ ± 0.5 ℃. Special attention should be paid to matching the mesh size of the filter at the inlet of the metering pump with the viscosity characteristics of the original solution to prevent degradation caused by shear overheating.
2、 Dynamic control of core process parameters
Four key elements need to be monitored synchronously during the spinning stage: the negative pressure value of the spinneret should be stable in the range of -0.03~-0.05MPa, and excessive fluctuations indicate component blockage; The concentration gradient of the coagulation bath should be designed to gradually increase from the inlet to the outlet, with a typical ratio of 8% -12%; The speed ratio error of the stretching roller shall not exceed ± 0.5%, and a closed-loop servo system shall be used for real-time correction; The pH value of the washing tank is maintained at neutral to alkaline to avoid fiber hydrolysis. The operator records the key parameter curve every hour and immediately activates the emergency plan upon discovering any sudden changes.
3、 Accurate handling of special working conditions
In the face of frequent wire breakage, priority should be given to checking the defoaming effect of the original solution, and the settling time should be appropriately extended to more than 48 hours; If the phenomenon of merging occurs, adjust the tension spring compression of the guide wire hook to make the single wire evenly stressed. During the roll changing operation, an automatic cutting blade is used in conjunction with a vacuum edge suction device to ensure the complete transfer of the fiber bundle. In case of sudden power outage, the metering pump should be immediately turned off, and the residual liquid in the nozzle should be manually drained by turning the disc to prevent the blockage of micro holes by the gel.
4、 Standard process for periodic maintenance
Perform a deep cleaning procedure after daily shutdown: disassemble the spinneret assembly, use an ultrasonic cleaning machine to remove crystals, and inspect the micro hole roundness of the spinneret plate under a microscope; Verify the zero drift of the pressure sensor weekly and replace the back pressure valve diaphragm; Conduct monthly full line air tightness testing, with a focus on inspecting the sealing surface of the flange of the coagulation bath sight glass. The inventory of vulnerable parts should have spare spinnerets from the same batch to ensure process consistency after replacement.
5、 Construction of Security Protection System
Implement a three-level protection system in the operation area: wear acid and alkali resistant gloves to handle coagulation bath replenishment operations; Configure emergency flushing devices to respond to sputtering accidents; Install heat shields on high-temperature components and set up infrared temperature measurement alarms. The storage of hazardous chemicals follows a double person double lock management, and the coagulation bath mother liquor is configured in an independent fume hood. Regularly organize emergency plan drills to ensure quick response to unexpected situations.
The efficient operation of wet spinning machines relies on the organic combination of standardized operation and refined management. Establishing a complete SOP system, implementing parameter traceability system, and cooperating with preventive maintenance plan can effectively improve the fiber qualification rate. It is recommended to conduct equipment capability verification every quarter, continuously optimize the process window through microscopic morphology analysis and mechanical performance testing. Only by combining the potential of equipment performance with operational standards can stable mass production of high-quality fibers be achieved.