FOCUS ON COIL PROCESSING
THE PRE- PAINTING PROCESS
Coil coating is a reel-fed continuous process for painting metal which is then used to make a finished part .
Coil handling crane .
Image : Street .
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pre-painted metal is one that has been coated with a material , like paint or film , to create a decorative , protective or other specific film . The process of applying the coating is called coil coating , and it is typically done on steel or aluminium .
Coil coating is a reel-fed continuous process for painting metal which is then used to make a finished part . In one continuous reel-to-reel process , a metal coil of material is unwound , cleaned , primed and then coated with up to
“ The use of pre-painted metal can improve overall productivity and yield , while reducing manufacturing , energy and inventory costs .”
two layers of paint on each side , before being thermally cured and then rewound .
The process allows for different colours and patterns to be applied to each side of the sheet . In addition , a strippable plastic film layer can be added for extra surface protection . Once coated , the coil is then further processed to give users the material in the dimensions and formats that they require . Manufacturers can eliminate their paint lines , which are usually major bottlenecks in their operations ,
NLMK coated coil . while capacity constraints are also minimised .
“ The consistency and accuracy of the coilcoating process generates excellent corrosion resistance properties compared to other painting methods . This is due to the highly controlled cleaning , pre-treatment , coating application and curing stages within the process . These controls are virtually impossible to attain with other painting processes . Dealing with a ‘ flat sheet ’ allows the material to be thoroughly cleaned prior to the paint being applied . Coating in this way provides excellent control of paint film weights , which can be measured in microns ,” outlined coil coating specialist , Cooper Coated Coil .
The benefits of coil coating
Coated coil can be slit for narrow widths , cut to required lengths , bent , profiled or deepdrawn without damaging the organic coating . It can be processed into any number of shapes , depending upon the end use . The coil coating process itself offers a range of economic and environmental benefits . It is a closed loop process so the release of harmful elements is eradicated . All solvents / organic compounds are captured and treated before emission .
The process also provides coating application efficiency of over 90 %, which is significantly higher than other application techniques . Pre-painted metals can also be fully recycled , providing further environmental advantages .
74 | ismr . net | ISMR December 2024 / January 2025