Controlling production of rubber strip

Pirelli has turned to PLCs and Scada to control calender line parameters in tyre production

Pirelli reports that it is making tyres of more consistent quality, and the efficiency of the line has been improved, thanks to new equipment installed to control calender line parameters, such as speed, tension and temperature.

The new control system is built on an Alstom GEM80-400 PLC and an Alspa P1200 Scada package.

Where it was previously the responsibility of an operator to make adjustments to the calender line parameters using potentiometers, now a `recipe’ can be selected via the Scada package and loaded into the PLC which automatically maintains precise, accurate control of the line. The package provides full mimic facilities including display of alarms and materials used. The operator is guided through each step by pull down menus, while future system compatibility is assured as user programs can be written and integrated to provide a solution that is tailored to the application.

The metallic calender line produces rubber strip which is embedded with wire strands. Via a weave bar, the line compresses 600 fine steel strands into a flat form shape. The band is passed in a continuous feed to a four roll calender. The top and bottom rolls are fed with rubber which is compressed into a membrane and is then amalgamated with the steel strands which simultaneously pass through the middle two rolls.

The resultant `metallic sheet’ product is fed to cooling drums then kept under tension in an hydraulic festoon before being spooled on to bobbins. The product is layered with an alkathene liner to stop each layer bonding to the next. It is then used in the nest stage of tyre production.

Alstom Drives & Controls Tel: 01782 781000