I. Upgrade to a Closed-Loop Tension Control System
Adopting a closed-loop control scheme using a high-performance vector frequency converter + tension sensor + PLC is currently the most effective technical approach.
1. Real-time Feedback Adjustment: By dynamically acquiring signals through the tension sensor, the system controls the response in milliseconds, automatically adjusting the motor torque to keep tension fluctuations within ±5%.
2. Automatic Roll Diameter Compensation: Combining encoder data with real-time calculation of roll diameter changes, dynamically adjusting speed matching to avoid tension imbalance caused by increased roll diameter.
3. Recommended Configuration: Use frequency converters with built-in tension control modules, such as the Huichuan MD330 or Delta VE series, to reduce external controller costs and improve integration.
II. Optimize Frequency Converter Control Modes and Parameters
1. Dynamic Switching of Take-up/Unwind Roles
The take-up side uses torque mode, and the unwind side uses speed mode. The roles are automatically switched after the roll reaches the end, ensuring constant tension.
2. Enable pre-drive and taper compensation functions. Set a reasonable tension taper (e.g., tighter inside, looser outside) according to the fabric type to prevent inner layer damage or outer layer loosening.
3. Finely adjust PID parameters. Optimize proportional, integral, and derivative parameters in the PLC to avoid overshoot or slow response, and improve system stability.
III. Strengthen mechanical system maintenance and calibration.
1. Check guide roller parallelism and surface condition. The parallelism deviation of the fabric winding roller and guide roller should be ≤0.5mm/m, and the surface should be smooth, without wear or foreign matter adhesion.
2. Clean yarn ends and remove contaminants. Regularly clean the yarn ends on the stainless steel roller at the bottom of the cylinder to prevent sudden changes in local resistance from causing tension fluctuations.
3. Calibrate the tension detection device. Regularly calibrate the tension sensor using standard weights to ensure detection accuracy and avoid miscontrol.
IV. Reasonable Setting of Process Parameters
1. Setting Tension Ranges According to Fabric Type
Lightweight silk and elastic knitted fabrics: 300–500N (low tension to prevent deformation)
Heavy cotton and polyester fabrics: 600–800N (high tension to prevent loosening and curling)
2. Controlling Operating Speed
It is recommended to control the linear speed at 15–20 meters/minute, especially for sensitive fabrics, to avoid high-speed amplification of fluctuations.
3. Maintaining Environmental Stability
Workshop temperature and humidity fluctuations should be controlled within a reasonable range to prevent tension changes caused by fabric moisture absorption or shrinkage.
V. Implementing Dynamic Monitoring and Preventive Maintenance
1. Real-time Monitoring of Tension Curves: View historical tension data through the frequency converter backend and intervene promptly upon detecting abnormal trends.
2. Establishing Inspection Logs: Regularly check bearing lubrication, transmission chain tightness, and electrical wiring integrity to prevent problems before they occur.
3. Test Dyeing of White Fabric for Verification: Conduct a no-dye test before formal production to observe the fabric surface condition and identify potential problems in advance.
