Easy open end evolution

Easy open ends at Friesland Foods, 2006. Image: Hoge Noorden / Jacob Van Essen

Evert van de Weg charts the history of easy open ends in both beverage and food can markets since the 1970s, following the developments up to the present day

 

Images courtesy of Wim Journee

 

I became aware of the developments in easy open ends (EOE) in the 1970s, while working at Dutch can maker, Thomassen & Drijver – Verblifa. I was selling twist-off closures at the time. Nevertheless I heard, via colleagues in the beverage can sales department, about the rapid construction of our new plant for two-piece DWI beverage cans, and another for EOE, all in close cooperation with our main shareholder and licensor, Continental Can Company, and the other licensees, Metal Box and Schmalbach – Lubeca. The rapid growth in consumption of two-piece beverage cans in the United States and Europe necessitated the production of a similar amount of easy open ends.

Around the same time, I also saw the first examples of EOE for food cans, although many highlighted that the pull tab often broke off from the panel of the lid for these, and that the forces needed to open it were much too high. The technologies involved in making EOE for beverage cans differ considerably from those for food cans.

From the 1970s onwards, the two-piece DWI beverage can, combined with its easy open end, conquered a large market share in the US and Europe. It revolutionised the beverage markets, in particular beer and soft drinks. The breakthrough of EOE for food cans, however, came much later, beginning only at the end of the 1980s and accelerating in the 1990s.

It was Ermal C Fraze who was at the forefront of the invention for the pull-tab easy open end. Fraze was an American citizen, living in Dayton and owning the tool making company, Dayton Reliable Tool & Manufacturing Company. Though times after World War II were rough, Fraze built a successful tool business. The story goes that Fraze and his family were out on a picnic in 1957 with some friends and he wanted to open a can of beer, but there was no ‘church key,’ the tool you needed back then to open the lid of a three-piece can. He had to improvise to open the can and reportedly said to himself: “There must be a better way.”

In 1987, Fraze stated in a speech that initially he had struggled to find an effective way to attach the tab to the easy open end. But after many sleepless  nights, he began to mathematically calculate the different formations, and, as he was familiar with the formability of aluminium, he finally found success.

The design used an integrated rivet to secure the tab. Fraze made some samples and his theory worked  well.  He  applied  for  patents  on  his invention and then invited the largest aluminium supplier at the time, Alcoa, to help launch his invention into the marketplace.

Alcoa signed an agreement giving it licensing rights for the United States and the remainder of the world. Fraze continued developing his easy open end design.

By 1977, he had patented the non-detachable version of his easy open end, so that the tab remained on the panel and prevented littering – accidental or otherwise. However, the non- detachable tabs were only introduced to Europe on a mass scale in the 1990s. This was an important improvement, but only one in a series of many in the design of EOE during the following decades.

Image: Wim Journee

Modifications and improvements

The driving force behind the birth of EOE and their ongoing improvement, is the demand for convenience by consumers and their representatives, the brand owners. The biggest challenges for tool designers, suppliers of shell presses and can makers, were (and still are) how to handle the pressures ends must cope with during filling and handling through the supply chain, and the convenience they must offer to consumers.

The most delicate operation is the execution of the end’s incision, to get the exact depth for the score to allow a smooth tear. If the score residual is too little, the opening effort will be excessive; if it is too deep, there is a high risk of spontaneous lid opening during the canning process, or later during consumer use. This is a real balancing act.

The pull tabs are manufactured and applied to the lids on the same multi-station press. The tool on this press to complete the easy open end has a very complex design, as the total manufacture of the ends requires up to 14 steps, depending on the design. Over the last few decades, companies such as Dayton Reliable Tools, Stolle and Minster improved the tools and the presses considerably, regarding exactness and output.

Recently, I heard from my former colleague and now senior technical expert in the production of EOE at Trivium, Henny Wiggers, that the output of today’s EOE lines has increased from some 800 ends per minute to over 5,000 ends per minute, in particular by the application of more lanes per line.

Beverage cans

Almost 100 per cent of EOE for carbonated beverages are made of aluminium, with non-detachable tabs.

Over the course of time, can makers have applied various modifications to EOE, including changing the shape of the lid, enabling aluminium reduction, and producing cans with full aperture ends, which transform the can into a cup. Easy open ends are

also now offered in striking colours, and tabs can be  lasered  with  messages,  or  codes  etched underneath and so forth.

Image: Wim Journee

Food cans

In the 1980s, there was limited availability of EOE for food cans. The ends were not reliable enough in performance and opening consistency, and also not convenient enough for consumers to justify the rather high price difference compared to cans with ‘normal’ ends. Thus, EOE gained hardly any share in the food can markets.

However, there was an increasing pressure from brand owners using food cans to offer their consumers the convenience of EOE. Brand owners of canned fish products in Germany, France and Spain asked for EOE for their often high-value products, and thus can makers such as Cébal, Mivisa and Schmalbach-Lubeca developed these for the often irregularly shaped cans (oblong, pear- shape, Hansa, Dingly). Bonduelle was among one of the first brand owners in Europe that began to use EOE on regular food cans.

However, the real breakthrough in Europe took place in the early 1990s, when pet food multinational, Mars, made a mega-deal with its can supplier, Carnaud-Metalbox (part of Crown today), for a European-wide transition of the Mars pet food brands to a new type of easy open end.

Carnaud-Metalbox claimed that its new EOLE ends were much easier to open. The company had worked on this development with the assistance of its tinplate suppliers and the suppliers of conversion presses.

The launch in 1993 was a tremendous success, and this inspired other can makers to begin work on similar developments. At that time, I was working in the marketing department of Impress, then the number two in food cans in Europe. Our Food Can group, then part of our ‘new’ company, Continental Can Europe, swore to pick up the challenge and to come to the market with at least the same quality of easy open end as the EOLE ends.

My technical colleagues in the project group, closely linked to our R&D centre in Crosmières, France, carried out many tests in the R&D centre and in the Deventer plant, and made several visits to DRT, Service Tool and Minster, all in the US. We also negotiated with steel suppliers about the suitable steel quality.

After some time, we were able to supply easy open ends with comparable properties. Whereas it was always a challenge to cover the score with a good coating, Impress was able to offer a more reliable, post-repair coating system, by using the newly developed electro-coating technology from Italian company, Corima, now part of SLAC.

To find out if our new easy open ends performed well enough, particularly regarding opening forces, I organised a great deal of consumer research, during which many people were invited to open various versions of these new ends, sharing their experiences with us afterward.

The real boost came when Heinz UK agreed a supplycontract with Impressin 1998. Heinzconverted to EOE for its complete mainstream offerings of canned baked beans, soups, spaghetti etc, filled in the company’s plant in Wigan. Heinz demanded a great deal from Impress, particularly concerning opening forces. Impress then launched an extensive R&D and investment programme to cope with these demands, as well as those from other large food canners. The conversion of all the Heinz food cans to EOE was such a success that the responsible Heinz manager at the time, Justin Caetano, said after the conversion: “We have now the world’s best beans under the world’s best easy open ends!”

EOE become standard

Today, in Europe at least, 100 per cent of beverage cans feature EOE, as well as more than 90 per cent of food cans. In the US, the percentage of EOE for food cans is considerably lower thus far.

Over the course of time, many improvements to existing EOE have been realised. The production of easy open ends has also been improved by the application of automated quality control, ever-better steel or aluminium grades and higher production speeds. Many new plants for EOE have been built during the last few decades, particularly in Southeast Asia.

In the meantime, easy peel ends start have started to take away some market share from EOE, but as a high-ranking manager of a can maker said about its latest version of easy open ends: “All in all, our steel easy open ends reach opening forces that are not much higher than easy peel ends, whereas steel and aluminium EOE have a price advantage and always have the robustness that makes them easy to process and to handle throughout the whole chain.” The latest important alternative in EOE for food cans, introduced this year by Eviosys, is the so-called direct peel end, a sleek, peelable, aluminium foil sealed directly on the can body. Eviosys calls it the Ecopeel (more detail on page 8). According to experts, this could once again change the food can market considerably, as it combines sustainability and maximum convenience. Easy open ends seem to be ever evolving.

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