Created on 11.20

Why Aluminum Foil and Lithium Battery Films Require Higher Precision Shaft Systems

Compared with standard packaging films, materials such as aluminum foil, lithium battery separator film, copper foil, and optical film are much more difficult to rewind. The reason is simple — these materials are extremely thin, sensitive, and require precise tension control during high-speed production.

Material Sensitivity and Processing Challenges

These materials typically have:

Feature	Result if the shaft is not precise

Very thin (4–25μm)	Breakage or wrinkles

Soft and scratch-sensitive surface	Surface dents, marks or coating damage

Very narrow tension tolerance	Density inconsistency or telescoping

High-speed operation (120–500 m/min)	Vibration or unstable winding

Multi-roll rewinding requirements	Uneven slip torque between rolls

Because the material tolerance is extremely low, any fluctuation in tension or torque will directly affect product quality and final yield.

Why Standard Shaft Systems Fail

Traditional winding shafts cannot provide:

•	Accurate micro-tension output

•	Uniform slip torque for multiple rolls

•	Smooth compensation when diameter changes

•	High concentricity and smooth contact surface

This results in:

❌ Tapered roll ends

❌ Surface scratches

❌ Wrinkles and film breakage

❌ Poor winding alignment

For high-value battery materials, this means scrap and financial loss — not minor defects.

Etto Precision Solutions

To solve these challenges, Etto Precision provides:

✔ Differential Slip Shaft

•	Automatic slip compensation

•	Stable micro-tension 

•	Ideal for high-speed multi-roll rewinding

✔ Dual-Airway Slip Shaft

•	Independent locking & slip regulation

•	Wider tension control range

•	Higher stability during long operation

✔ Air Shaft + Magnetic Powder Brake System

•	Closed-loop tension control

•	Suitable for foil and battery separators

Conclusion

Aluminum foil and lithium battery film demand precision.

With Etto Precision’s advanced shaft and tension control systems, manufacturers can achieve:

•	Perfect roll edges

•	Higher production speed

•	Lower scrap rate

•	Stable, repeatable winding quality