The process of painting metal using a continuous coating line was invented in the 1930’s in The USA by Joseph L. Hunter. He was known as a talented inventor, regularly designing new machines to improve the productivity of his venetian blind business. It took considerable time for this invention to catch on to industry worldwide though.
► In 1964, Head Wrightson built a prototype continuous coating machine at their Research & Development Division at Thornaby‐on‐Tees to investigate the process and subsequently published a paper entitled “Continuous coating of metal strip: a new process for the application of paints, plastics and metallic powders”
►By 1967 the first continuous spray painting line was introduced at Shotton Works at the newly nationalised British Steel works (previously John Summer & Sons)- albeit with only green, grey and brown as colour options used mainly in agricultural buildings. The first roller coat continuous paint coating line was commissioned at Shotton Works in 1978.
►From the 1980s to the turn of the 20th century continuous coating lines became popular the world over with every major industry utilising the continuously painted sheet steel in a huge variety of colours, finishes and qualities. (read about the many layers of prepainted steel in a previous blog here)
►Developments are constantly being made to advance the process of continuous painting of steel which can now reach speeds of up to 200m per minute. Larger lines typically incorporate one, or more, accumulators so that the line doesn’t have to be stopped or slowed which would cause issues further down the line. There’s a rumour that some accumulators in the USA are so high that they have had to get air traffic clearance!
►End users have high expectations of aesthetics, uniformity and performance and the process of continuous painting of sheet offers huge advances on previous methods of painting steel including:
• Consistency of colour and finish quality throughout the product.
• Consistency in the thickness of application which ensures only the exact amount of paint needed is used.
• A huge range of surface finish design options e.g. embossing and leathergrain.
• No loss of paint during application which makes it significantly less damaging to the planet.
All of which ensure the longevity of the product leading to some incredible guarantees such as the Tata Steel's Confidex Guarantee of up to 40 years
