Influence of Material Properties on Pet-Hair of Laminated Steel in The Forming Process of DI Can

Beverage cans have being produced mainly with draw and ironing (DI) process since 1971. The cans in the process are formed in wet condition, generally followed by being washed and lacquer-coated. In 1992, a dry forming process using polyester film laminated steel, called Stretch and Draw forming, was developed. Application of Polyethylene terephthalate (PET) film laminated steel to DI process was expected to be beneficial but had a problem (hereinafter referred to as PET-hair) of film shaving or breaking at formed can edge due to no flange making in process. The PET-hair generated on the condition of over 15% in ironing rate, indicating it was difficult to make can body thinner and the laminated material could not be applied for DI process. In this background, we investigated the influences of film thickness, film properties and substrate yield point on PET-hair generation, and obtained the following findings. Firstly, thinner films tend to get PET-hair reduced. Secondly, film properties impact little on PET-hair due to the temperature increase by process heat generation. Thirdly, the substrates with lower yield point tend to get PET-hair reduced.