An extrusion-coating or extrusion-laminating control system includes extruder control, web-tension control and data acquisition. Extruder control covers temperature regulation and coating-thickness control.
Temperature control
The temperature system is modular. Each zone has an independent CPU for its control calculations. The PID algorithm provides rapid heating and stable temperature holding. Each extruder forms a station connected to the supervisory computer through real-time industrial Ethernet, with attention to interference resistance.
Thickness control
A high-speed PLC performs the coating-thickness calculations. The system reduces the need for operators to rely on experience and repeated manual calculation. It automatically maintains coating thickness during acceleration, deceleration and operation at different line speeds.
Web-tension control
The feedback method is selected for each part of the machine: dancer, load cell or a combination of both. Unwinds and rewinds can change rolls automatically at high speed. Actuators include vector drives and asynchronous servos; passive unwinds use pneumatic or electromagnetic brakes.
Data acquisition and remote access
The system records production temperatures, speeds and other process data, and can archive recipes by product. Data is stored in Excel files. Operators can view it locally or access saved data over the network through the system’s web server. An FTP server can back up data to another computer on the network.
An OPC interface supports connection to ERP systems. Remote monitoring and maintenance are supported over ADSL or 4G connections.