I. Inappropriate Taper Coefficient Setting
Error Manifestations: A taper coefficient that is too large results in excessively rapid tension decay, leading to an overly loose outer layer; a coefficient that is too small results in insufficient tension decay, causing severe pressure on the inner layer.
Typical Consequences:
Too Large: Loose winding, interlayer slippage, sudden tension changes during unwinding.
Too Small: Inner layer crushing, material deformation, core damage.
Correct Practice: Recommended linear taper setting range: tension decreases by 3%~5% for every 10cm increase in roll diameter. The thicker the material, the larger the required taper; it is recommended that the taper adjustment be proportional to the material thickness.
II. Initial Tension Setting Too High or Too Low
Error Manifestations: Initial tension is set blindly based on experience without calculating according to material characteristics.
Typical Consequences:
Too High: Thin film materials exhibit translucency and tensile deformation.
Too Low: Fabric materials become loosely wound; film materials contain air bubbles.
Correct Practice: Estimate tension using the formula: Tension (N) = Material Width (m) × Set Coefficient (N/m), and fine-tune through trial runs until the edges are free of wavy wrinkles.
III. Failure to Enable "Soft Start" Function Leads to Material Breakage During Roll Change
Incorrect Symptom: Tension is not buffered during roll change, switching directly to the normal value.
Typical Consequences: Instantaneous tension impact causes film breakage, especially frequent at high speeds.
Correct Practice: Enable the "Soft Start" function. At the moment of roll change, reduce the tension to 70% of normal, then gradually restore it after 2 seconds for a smooth transition.
IV. Neglecting Calibration of the Roll Diameter Detection System
Incorrect Symptom: Proximity switch misalignment, loose wiring, or sensor malfunction leads to distorted roll diameter feedback.
Typical Consequence: The tension controller misjudges the current roll diameter, causing taper control failure and resulting in "false large rolls" or "false small rolls."
Correct Practice: Regularly perform manual operation to verify the accuracy of the roll diameter readings. If deviations are found, adjust the sensor position or replace components promptly.
V. Imbalance in Unwinding and Rewinding Tension Ratio
Incorrect Manifestation: Unwinding tension is greater than or equal to rewinding tension, disrupting the tension gradient.
Typical Consequence: The material is stretched in the opposite direction, resulting in serpentine deviation, wrinkling, or even breakage.
Correct Practice: Follow the basic principle of unwinding tension : rewinding tension = 1 : 1.05~1.1 to ensure a smooth material transition.
VI. Failure to Differentiate Adjustments Based on Material Type
Incorrect Manifestation: Using the same parameter template for all materials, lacking specificity.
Typical Consequences:
Thin Films (e.g., EVA/PO): Excessive tension causes translucency.
Fabrics (e.g., nonwovens): Excessive tension causes fiber deformation.
Sensitive Materials (e.g., optical films): Environmental fluctuations combined with unstable tension affect surface quality.
Correct Practices:
Thin Films: Tension controlled between 2~5kg.
Fabrics: ≤ 3kg.
Sensitive Materials such as Optical Films: Use closed-loop control and a stable temperature and humidity environment (23±2℃, RH 50%±5%).
VII. Neglecting the Monitoring Role of Floating Rollers
Incorrect Manifestations: Floating roller jamming, abnormal sliding resistance, or not installed in the pre-lamination stage.
Typical Consequences: Inability to detect tension fluctuations in real time; the system cannot compensate in time, leading to material shifting or wrinkling.
Correct Practices: Install floating rollers in the pre-lamination stage, ensuring their sliding resistance is within the range of 0.5~1N. Tension adjustment is required if it exceeds ±5mm.
