If this stress becomes greater during winding, the inner wraps towards the core will be put under high compressive loads.
The good solid foundation requires starting the winding operation on a high-quality, properly stored core.
The next unsuitable manner to eliminate the sensor is to measure the impedance change of the motor windings by injecting a high-frequency sense carrier, or probing with current pulses.
Our new approach measures the motor windings impedance ratio.
Key considerations in applying the nip principle of winding are:
* The nip must be applied where the web enters the winding roll.
The best strategy is to wind with the least tension possible because you are winding
a rubber band.
Better low-tension control improves roll quality for cast PP film, which is a difficult product because it keeps shrinking as it crystallizes for 48 hr or more after winding. If enough air isn't wound into the roll to allow for that shrinkage, the roll hardens and can crush the core.
It has a bank of 13 AC servo motors with direct torque control--six per winding station plus one for the input nip.
The second lay-on roll is speed-matched to the web and is positioned just above the first or primary lay-on roll during winding. During indexing and cutover, the auxiliary lay-on roll is temporarily connected to the turret by an arm and moves clockwise along with the finished roll.
A new clamshell mechanism that clamps both ends of the shaft is said to reduce vibration during high-speed winding of wide rolls and allows thinner (3-in.) cores to be used.
As just one example, high winding
speeds and heavy loads make cores vulnerable to the shear stress that commonly occurs when the chuck does not penetrate far enough into the core.