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design. “When you consider the tolerances involved in a modern production line, ultra-thin walls are only realisable thanks to development in the metals that are used,” says Dan Abramowicz, Executive Vice President Technology and Regulatory Affairs, Crown Packaging Technology. “Going thinner increases the risk of tearing, which creates a demand for higher quality. The metal must have fewer imperfections and the equipment must be consistent. From this point of view, thinner can walls would not be possible without a cooperative relationship between stakeholders, and a whole supply chain pulling in the same direction.”“Thinner walls are also possible thanks to the use of more accurate machines,” adds Bill Neilson, “because quality is such a prerequisite when working with such thin walls. These days we have machines running at high speeds at an accuracy of 6μm. Another big step forward is the introduction of smart machinery, bringing automatic sampling, constant measurement and the utilisation of statistics on the factory floor. More measurement leads to better quality.”THERMOCHROMIC INK Perhaps the most striking recent development in can technology from a consumer’s point of view is the emergence of cans that change colour. This is made possible by the use of thermochromic inks or dyes: temperature-sensitive Left Dan Abramowicz, Executive Vice President Technology and Regulatory Affairs, Crown Packaging Technologycompounds that temporarily change colour with exposure to a temperature change.“Thermochromic inks come in two forms: liquid crystals and leuco dyes,” explains Werner Noll, Manager Product Finishing, Ardagh Group. “After absorbing a certain amount of energy, the crystalline or molecular structure of the pigment changes in such a way that it absorbs and emits light at a different wavelength than at non-activated temperatures. This triggers the colour change.” While some eye-catching solutions have already hit the market, this is an area in which there is a sense that there is much more to come within an industry well aware of the potential applications. “The possibilities for improved functionality and differentiation are very exciting,” observes Dan Abramowicz. “You can have a thermometer that tells you when your beer is cold enough or one which indicates that an infant formula is at the correct temperature. Then there are decorative opportunities – such as the personalisation you can get from creating your own hand print, and there is growing interest in the design implications of a thermochromic ink with irreversible colour changes.”The industry, according to Bill Neilson, is working hard to develop more marketable solutions. As manufacturers bring down costs and optimise durability, consumers will see a lot more chameleon-like cans on the shelves and in refrigerators.NEW SHAPES While beverage cans have grown ever thinner, they have also undergone a proliferation in shapes and sizes. Brands seeking differentiation on the shelf are eager to use the form to establish a relationship with the consumer and influence decisions at the point of sale. Memorable examples of this include the sleek contours of the Red Bull can and the iconic shape of Heineken’s keg can. The challenges involved in creating a family of cans based on the same shape are not insignificant. “We have to deal with a material deformation history which only allows for limited shaping,” explains Pim van Dam. “A wall-ironed body is close to the end of ductility (breaking point) as far as elongation is concerned. This limitation can only be stretched by highly cost intensive measures. Traditional and special shaping routes were not very successful.”In the face of these challenges the industry has explored and learned lessons from mechanical shaping, explosion forming, electromagnetic forming, blow-moulding and high pressure hydro forming. “We keep an eye on what is possible with laser treatments and other means of metal manipulation,” adds Mr van Dam.One of the most effective areas of innovation in shaping has proved to be embossing. “With this the industry has created great effects, and millions of ➤ EUROPEAN CAN MARKET REPORT 2016 19INNOVATION