Rewound roll quality

Factors of importance are reviewed as follows:
1. A perfect reel: A rewound roll of high quality cannot be expected to result from a poor reel. A wrinkled reel is the result of hard and soft areas in the sheet that can be traced back to incorrect slice setting or uneven pressing or drying. Calender cuts are the result of over-drying and creases caused
by felts; slugs and shives can be traced back to the stock and cleaning conditions.
2. The slitters: A shear-cut slitter assembly should be used to minimize slitter dust. The slitters should be kept as sharp as possible, checked regularly for wobble, and a grinding schedule initiated to ensure optimum slitting at all times.
3. Winder drum draw: The draw between the winder drums should be reduced as the roll being wound increases in weight and diameter. This reduces the tendency to have an uncontrolled draw with increasing roll hardness, which on certain grades can be the limiting factor on rewind diameter.
4. The paper run: The sheet should be threaded up between the drums. This ensures a tightly wound roll since the wrap increases as the roll diameter increases, which helps to keep the slits separated.
5. The core shafts: The core shafts should be tightly locked in the holders and there should be no lateral movement. Uneven and dished rolls may otherwise result from uneven feeding onto the rewind roll.
6. The reel bars: The reel bars should be properly designed to prevent whipping at maximum winder speed. A fluttering or bouncing sheet will minimize good slitting and tension control.
7. The rider roll: The rider roll must have sufficient weight to provide good drum traction on starting and tight winding on the core. As the roll builds up, the weight of the paper will provide its own traction. If the rider roll has a counterweight beam controlled by pneumatic cylinders, it is very important to have equal pressure on each cylinder, equal lengths of suspension chain, and equal clearance on the slides to produce even loading on the rolls.
8. Sheet tension: Sheet tension is one of the most important factors in producing good winding. The amount of tension necessary depends upon the parent roll size, the type of paper being run, customer requirements, etc., and can be determined only by each individual mill to suit their own
requirements or standards.
9. Cores: The core diameters should not vary more than 0.40 mm; otherwise slack starts occur on some cores, different roll diameters are produced, rider roll pressure is uneven, wrinkles occur, and sheet tension is not uniform.