Tension fluctuations during fiber calendering can result from inaccurate roll alignment, inconsistent process parameters, unstable material feeding, or problems with the drive system. To stabilize tension, inspect the roll assembly, check the control system, maintain consistent material properties, and follow a structured maintenance procedure.
Roll alignment and mechanical maintenance
Check roll accuracy regularly with a dial indicator. Keep radial runout within 0.02 mm and roll parallelism deviation within 0.01 mm/m. Misaligned rolls can create uneven material tension across the working width.
Calibrate the tension sensor monthly using standard calibration weights to correct zero point errors and improve measurement accuracy.
Inspect the fastening bolts on the bearing housings and the roll coupling flanges. Tighten any loose connections to prevent fluctuations caused by transmission play.
Clean fiber debris and scale from the roll surfaces regularly. A consistent roll surface finish helps reduce variations in local friction that can affect material tension.
Process parameter control
Stabilize the processing temperature
Set the heating temperature according to the fiber material properties and keep temperature fluctuations within ±2°C. Temperature variations can change the material's stretching behavior and, consequently, its tension during processing.
Synchronize the equipment speed
Use a PLC system to coordinate the speeds of the upstream feeding equipment, calender rolls, and downstream winding unit. Keep the deviation in the speed ratio between equipment sections within 0.5% to reduce sudden tension changes caused by speed mismatches.
Optimize the roll gap
Adjust the roll gap according to the required finished fiber thickness. The gap should remain uniform across the working width. Local differences in clearance can produce uneven compression and contribute to tension fluctuations.
Introduce closed loop tension control
A closed loop feedback system can collect tension data in real time and automatically adjust the haul off roll speed or roll gap. The target is to maintain tension within ±5% of the setpoint.
Material and feeding consistency
Control raw material moisture
Moisture content should be controlled according to the fiber type. The specified limits are ≤8% for natural fibers and ≤0.5% for synthetic fibers. Excessive moisture can affect fiber tensile properties and lead to changes in tension during processing.
Maintain a consistent feed rate
Use gravimetric feeding equipment to control the amount of material supplied per unit length, keeping the deviation within 1%. This helps prevent tension fluctuations caused by uneven feeding or interruptions in the material supply.
Keep material batches consistent
Where possible, use fiber material from the same production batch. Differences in tensile strength and elastic modulus between batches can change how the material responds to stretching and contribute to unstable tension.
Routine maintenance and troubleshooting
Check drive belt tension regularly. When pressed by hand, the belt should deflect by approximately 10 to 15 mm under the specified check. Insufficient tension can cause slippage and speed fluctuations.
Maintain the lubrication system by applying the specified lubricant to roll bearings and drive gears according to the maintenance schedule. Proper lubrication helps keep friction in the drive components consistent.
When tension fluctuations occur, first verify that the tension sensor readings are reliable. Then inspect the roll surfaces and drive components before making changes to the process parameters. This sequence helps distinguish measurement problems from mechanical faults and process related causes.
Before carrying out maintenance, disconnect the power supply and follow the lockout/tagout procedure to prevent accidental startup.
Custom precision machining for calendering equipment
When worn or damaged mechanical components affect equipment accuracy, Hansheng Automation provides custom precision machining based on customer supplied drawings. We manufacture nonstandard parts according to specified dimensions and structural requirements to support equipment maintenance, component replacement, and custom manufacturing.
Our machining services also cover precision components for tobacco packaging and filling machinery, along with structural parts for yachts and remote control racing cars. Each component is produced according to the customer's drawings and application requirements.
