Solve common problems in ribbon slitting: flash, staggering and tension control

Flash, staggering and tension control problems that occur during ribbon slitting can have a direct impact on product quality and production efficiency. Here are the systematic solutions to these problems:

First, flashing problem (uneven edges/fibrous burrs)

1. Cause analysis

• Blade passivation or improper installation

• The slitting speed does not match the material

• The ribbon material is highly brittle or has poor coating adhesion

• The surface of the guide rollers is worn or not cleaned sufficiently

2. Solution

• Tool optimization:

◦ Use a high-hardness round knife (e.g., diamond-coated blade) and check the sharpness of the cutting edge regularly (every 8 hours).

◦ Adjust the blade angle to 15°~20°, and use single-sided bevel cutting to reduce edge stress.

• Process Adjustments:

◦ Reduce the slitting speed (recommended initial speed ≤50m/min) and gradually adjust to the best parameters.

◦ Preheating ribbon (40~50°C) improves the cutting performance of brittle materials.

• Ancillary measures:

◦ Add a static eliminator (e.g., ionic air bar) to reduce static adsorption of debris during cutting.

◦ Use a slitter with chip suction device to clean the cutting area in real time.

Second, the problem of staggered layers (interlayer deviation of coil material/serpentine)

1. Cause analysis

• Unwinding/rewinding tension is uneven

• The initial winding tightness of the parent roll is inconsistent

• Slitter Guiding System (EPC) response lag

• Fluctuations in ambient temperature and humidity cause the material to expand and contract

2. Solution

• Tension Control:

◦ Closed-loop tension control system is used to set the gradient tension curve (such as unwinding tension decreasing by 3%~5%).

◦ Constant tension maturation (tension ≈ 5N/cm²) for 24 hours before slitting.

• Equipment calibration:

◦ Check the sensitivity of the EPC sensor every week, and the deviation correction accuracy should be ≤±0.2mm.

◦ Use a laser alignment instrument to adjust the parallelism of the guide rollers (deviation < 0.05mm/m).

• Operational Specifications:

◦ Check the flatness of the end face of the parent roll (runout<1mm) before slitting.

◦ Operate in a constant temperature and humidity environment (23±2°C, RH50±5%).

Third, tension control problems (breakage/relaxation)

1. Critical Control Points

• Segment control: Divide the slitting process into 3 tension zones:

◦ Unwinding zone (tension A): Remains stable and avoids abrupt changes.

◦ Slitting area (tension B): 10%~15% lower than unwinding tension.

◦ Winding zone (tension C): Taper control (initial tension is 120% of B, decreasing linearly to 80%).

• Dynamic Monitoring:

◦ Install a high-precision tension sensor (e.g., METTLER TOLEDO) with a sampling frequency of ≥ 100Hz.

◦ Set belt break warning (automatic speed reduction when tension fluctuation >±5%).

2. Special scene processing

• Thin ribbon (<8μm):

◦ Use an inflatable shaft to wind, and the contact pressure ≤ 0.15MPa.

◦ Add floating rollers to the slitting area to cushion tension impacts.

• High viscosity coated ribbons:

◦ Install a release liner before winding.

◦ After slitting, let stand for 4 hours and then rewind to release internal stress.

Fourth, comprehensive preventive measures

1. Equipment Maintenance Table:

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2. Material Suitability Test:

• The new batch of ribbons needs to be tested in small rolls (length ≤ 100m) to test:

▪ Slitting speed limit value (critical point of flash)

▪ Optimum winding hardness (Shore A60~70 degrees)

Through the above methods, the burr rate (<0.1%), the incidence of cross-layering (<1 time/10,000 meters) and the stability of tension control (fluctuation <±3%) can be significantly reduced. It is recommended to cooperate with the MES system to record the slitting parameters and establish a process database to achieve continuous optimization.