The Holy Grail, Six Tips for Winding

1. Be sure the web material is as flat as possible

Process coming into the winder needs to be consistent

Basis weight and moisture variations must vary <5% across the web

The winding operation cannot improve the web material

2. Incoming web tension must be under control and measurable

Web tension cannot vary more than ±5% during steady state winding from setpoint

Web tension cannot vary more than ±10% during acceleration and deceleration

Transducers need to be provided for a direct readout of incoming web tension

3. Start winding with a good foundation

Wind on as large a core outside diameter (OD) as possible

Start winding on a good quality, well-dried core

Start winding with first wraps on the core as tight as possible

4. Wind with tapered roll hardness

After achieving a good hard start, taper the roll hardness as the roll winds

Gradually taper roll hardness through one or more of the TNT Principles

Taper the roll’s hardness between 25%–50% of starting hardness

Hardness tapering prevents defects such as dishing, starring, buckling, telescoping while unwinding

5. Avoid winding too tightly as excessive roll harness can cause the following problems

Blocked rolls with sheet layers that fuse or adhere together

Exaggerated web defects, such as high caliper areas building on each other

Gauge bands that produce corrugations or rope marks in the tightly wound roll

Bagginess upon unwinding

6. Wind sufficient air in low areas and prevent stretching over high areas



Davis-Standard: www.davis-standard.com

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