Why are the steps in “dipping”?

1. Unwinding with accumulator
2. Tensioning
3. Dipping
4. Drying
5. Rewinding

1. Unwinding with accumulator
The unwinding station has to unwind reels and have facilities for fast
changeover of reels. Before a reel change the accumulator is full. The cord
web is stopped with a brake and the new web is jointed to the old one by
curing which takes about 2 min at a temperature of 150 degrees
Centigrade, while the line is supplied with cord web from the accumulator.

2. Tensioning
The synthetic cord must be tensioned and fixed at high temperature to
avoid elongation and form changes (dimensional stability) in the final
finished product i.e. tire. During he tensioning under heat the cord is
subject to a temperature of ~ 230 degrees Centigrade for ~ 45 seconds, at
the same time as it is stretched. The elongation is ~ 2 – 10 %.

3. Dipping
The cord is led via deflection rolls into a container with impregnating
liquid. After the dipping the material is passing via pressure rolls and a
vacuum section station to recover excess impregnation liquid. The dipping
is sometimes done before tensioning.

4. Drying
The drying is performed in a drying chamber with air of ~170 degrees
Centigrade. After drying the cord is cooled by cooling rolls.

5. Rewinding
The rewinding section consists of accumulators and winding reels and
works in a similar way as the unwinding section.

The DIP line is a very critical process. The stretch and tension in the line
determine the final quality of the tire as well as its adhesiveness to rubber during
calendaring.

Traditionally all the drives used are DC drives with 4Q operation to enable fast
stopping of the line during fabric break or power failure (in which case DBR is used). But
a possible configuration would be a multi drive unit comprising of ISU (IGBT supply
unit) and individual inverters.
The accumulator level sensor control is same as that in calendaring.
Here also the winder is in indirect torque control mode with diameter calculation.

The reference to all the drives contains maximum four quantities.
They are:

The line speed reference.

Dancer feedback to all the drives before it i.e the entry feed
rolls (entry side) and after it (depends on configuration)

A trim (or stretch or draw): Same as in calendaring but in this case
usually only the pull rolls get the trim.

Load cell (optional) feedback to all the pull roll drives.