The Coil Coating Process

The metal substrate, whether steel or aluminum, is typically delivered in coil form from rolling mills. The weight of these coils can vary significantly, ranging from 5 to 6 tonnes for aluminum and up to 20 tonnes for steel.

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The coil is positioned at the start of the line and unwound at a consistent speed. It passes through various pre-treatment and coating processes before being recoiled for packaging or further processing.

To ensure a continuous operation, two strip accumulators are located at the beginning and end of the line. This setup allows new coils to be added and completed coils to be removed via a metal stitching process, without the need to halt or slow down the production line.

If you seek further details, please visit Coating aluminum coil for packaging.

The following sequence of operations takes place on a modern coating line:

• Mechanical stitching of the strip to its predecessor
• Cleaning the strip
• Power brushing to enhance surface quality
• Surface treatment through chemical conversion
• Drying the strip for optimal coating adhesion
• Applying primer on one or both sides as needed
• Passage through the first curing oven (lasting between 15 to 60 seconds)
• Cooling the strip before the final coat
• Finishing coating applied on one or both sides of the strip
• Passage through the second curing oven (also lasting between 15 to 60 seconds)
• Cooling down to ambient temperature
• Rewinding of the coated coil for storage or transport.

Coil Coating Process

Entry End

Uncoiler

Heavy metal coils, weighing up to 60,000 pounds, are received at this stage and undergo a visual inspection to ensure quality before they proceed to the uncoiler for unwinding.

Coil Stitch

During this phase, the ends of the current coil are mechanically joined with the ends of the new coil, maintaining a seamless flow through the coil coating line.

For additional information, please check Coating aluminum coil for electronics.