Heinz wraps up lightweighting

The  Canmaker
April 2007

The recent project at Heinz to cut the weight of its easy-open ends has shown how environmentally-prompted activity can also improve the bottom line. John Nutting reports

Canmakers have never wanted to make cans that are heavier than they need be. But the challenge has always been to reduce weight while maintaining the can's resistance to damage during processing and shipping - activities that are often out of their control.

Now with sustainability, energy reduction and impact on the environment increasingly fashionable there are stronger incentives for retailers, food and drinks producers and canmakers to collaborate in weight saving programmes that have a beneficial impact throughout the supply chain.

In the UK, the government's WRAP (Waste & Resources Action Programme) has been offering financial carrots that have already produced results. One of the most successful was a joint project between canned food producer Heinz, canmaker Impress and steelmaker Corus to reduce the gauge of easy-open ends on products such as Heinz Baked Beans and Tomato Soup.

With those two brands worth £300 million (US$580m) a year in sales, Heinz was concerned about the impact on its operations at Kitt Green in Lancashire. Which is why in May 2005 - after Heinz's application to the WRAP Innovation Fund was accepted and a £250,000 ($480,000) grant agreed - the project was started and carefully managed to ensure that the new ends were introduced with the least disruption.

For Heinz, cost savings of more than £400,000 ($775,000) have been made. But environmentally there's also been a benefit, with fewer trucks transporting the ends and less steel reaching the waste stream. WRAPreckons that the energy reductions from the project have saved more than 2,000 tonnes of carbon dioxide emissions.

Now Heinz is working on lightweighting its can bodies. This is just as challenging as lightweighting ends because using tinplate sheet of less than the current 0.14mm gauge requires changes both in canmaking plants and processing operations.

One leading canmaker said that while it has always been working on lightweighting, they've now arrived at a stage where the risks of damage outweigh the benefits.

"We are reaching the point where we are increasingly having to closely weigh up the benefits of lightweighting for our customers against increasing the risk of container abuse in the market place," he said. "I'm not sure whether WRAP appreciates this."

Which makes the success of the Heinz project all the more impressive. At Kitt Green, it makes many of the billion-a-year cans that it fills. The easy-open ends are made by Impress at Deventer in the Netherlands, and what balance of threepiece welded cans required are made at the Impress plant in Sutton-in-Ashfield, Nottinghamshire.

Impress has supplied ends and cans to Heinz ever since it did a deal to take over the food manufacturer's worldwide canmaking operations in 1999, but with the Kitt Green lines so tightly integrated into the canning plant, the biggest of its type anywhere, Heinz retained them.

It was important to trial the new lighter end design to ensure that it would perform as well as, if not better than, the existing ends used by Heinz. Key to this was that the lighter end had to feel no different to the consumer and that its performance during filling, processing and packaging remained unchanged.
Impress had already been refining its end-making lines at Deventer with the statistical control of processes and of the temperature of its conversion presses. This reduced the variability of the opening forces for the 73mm-diameter ends it was producing.

"Lightweighting food cans is not as straightforward as it might first seem," said Impress's technical director Gerald Sturdy. "Our 60-strong innovation team had to overcome a number of technical challenges to ensure that the integrity of the can, its look, feel, strength and behaviour, remained unchanged.

"With easy-open ends the industry had gone down to 0.20mm gauge and was stuck at that," said Sturdy. "And we were doing some work to get to 0.19mm. But even this was regarded as the rocket science of the canmaking business and right at the top end of the technology."

Further discussions at Impress's research and development centre at Crosmières in France fuelled confidence in the possibility of going down to 0.18mm. "We thought at first we were going a bit far," added senior R&D manager Ad Emmerzaal, "but because we had control of the manufacturing process we concluded it was achievable."

So making the ends in a thinner gauge wasn't the main problem. The key challenges were to control wrinkling of the seam during the seaming operation - always a problem with harder doublereduced steels - and making the end withstand the pressure variations during heat processing after filling.

Tighter control of redesigned chuck and roll tooling in the seaming overcame the first challenge. Impress designers then employed finite-element-analysis programs to evaluate a new panel design before a batch of 30,000 ends were made on a Minster press with Service Tool tooling that was used for prototyping at Crosmières. "Using this press meant that we didn't have to interrupt production at Deventer," said Emmerzaal.

Result was the world's lightest easyopen end for 73mm diameter 200g and 400g welded food cans. The ends are 13 percent lighter than the ends previously used by Heinz, and as much as 25 percent lighter than some easy open ends on the market.

The first 0.18mm ends were rolled out at Kitt Green early in 2006 and by the end of the year all the filling lines were using them.

As well as performing well on supermarket shelves, the groundbreaking cans have shown how development is capable of making dramatic savings in the manufacturing and supply chain process in three areas: less steel is required; producer responsibility costs are reduced; and transport costs are lower.

Because of the reduced metal content Heinz has cut the cost of its ends by £404,000 ($782,000) a year, or 4.2 percent.

Another less obvious saving is in transportation costs. More ends - around 390,000 or 18 percent - can be shipped in each truck load, reducing the number of deliveries, labour costs and fuel. There is also a weight saving of 83kg per lorry load.

Other environmental benefits accrue from a yearly reduction of 1,400 tonnes of steel used - the production of which would have generated 585 tonnes of car- bon dioxide - and less steel in the domestic waste stream. Using lightweight ends also saves energy: 11,460 kilowatt hours per million through the chain.
And with Packaging Recovery Note (PRN) prices ranging up to £100, a further saving of £88.40 is achieved for every million ends used.

The process proved, emphatically, that lighter ends can be integrated into the production process, and that payback times for investment can be commercially viable.

Inevitably, some modifications to the manufacturing process were needed. Corus supplied double-reduced steel for the new can end. Meanwhile, minor changes were introduced on the canmaker's flangers, to marry the can body with the new end. On-line testing machinery also had to be modified to accommodate the revised dimensions of the new package.

The new lightweight can ends were not interchangeable with the previous version on the filling line, which meant that a careful planning exercise had to be implemented to use up the old stock and introduce the new ends, without incurring write-offs or machine downtime.

Heinz customers, which are largely retail multiples, are also reaping the benefits. The new lightweight cans are helping them to meet packaging waste reduction targets of the UK's Courtauld Commitment, which requires retailers, brands and their supply chains to design out packaging waste growth by 2008 and deliver absolute reductions in packaging waste by March 2010.
Given that easy-open ends in the UK can still be as thick as 0.23mm, other manufacturers stand to make impressive savings by following the Heinz example. WRAP estimates that cost savings of the new end will, in general, be in the order of three to four per cent of total end costs.

If just half of the UK's 2.5 billion food cans used the lightweight ends, the industry could save 14.4 million kilowatt hours every year, which equates to more than 1,170 tonnes of carbon emissions. The Heinz project has shown that reducing the weight of three-piece easyopen can ends can reduce costs, waste, energy use and emissions while retaining valuable brand integrity.
The next steps are to ensure that the results of this Innovation Fund project are disseminated widely and that the improvement is rolled out across the canmaking industry. Further work is also required to identify ways of further reducing the amount of material used in each can.

Heinz is now aiming to reduce the wall thickness of its can bodies. Many canners in Europe use containers for food with a gauge of 0.14mm and some pet food manufacturers 0.13mm. Heinz currently uses 0.150-0.155mm and is expected to aim for 0.14mm, offering weight savings of almost 10 percent.
WRAP is also holding discussions with other canmakers and fillers to look at the possibility of using lightweight easy-open ends at other plants and creating further weight reduction opportunities.

What's WRAP?
WRAP works in partnership to encourage and enable businesses and consumers to be more efficient in their use of materials and recycle more things more often. This helps to minimise landfill, reduce carbon emissions and improve our environment.

Established as a not-for-profit company in 2000, WRAP is backed by substantial Government funding from Defra and the devolved administrations in Scotland, Wales and Northern Ireland.

Working in seven key areas (Construction, Retail, Manufacturing, Organics, Business Growth, Behavioural Change, and Local Authority Support), WRAP's work focuses on market development and support to drive forward recycling and materials resource efficiency within these sectors, as well as wider communications and awareness activities including the multimedia national Recycle Now campaign for England.

WRAP's retail team is working with the retailers and their supply chains to reduce the amount of packaging and food that households throw away.
More information on all of WRAP's programmes can be found at www.wrap.org.uk 

What if?
Around five billion cans are used for human and pet foods every year in the UK, a market that is worth £3.7 billion. Half of these, 2.5 billion, are made in the UK.

If the savings made by Heinz were extended through the whole of the industry, 28.8 million kilowatt-hours of energy and 2,340 tonnes of carbon dioxide emissions would be saved, says WRAP.

The 1,400 tonnes of steel saved would also reduce the volume in the domestic waste stream. Extending this to the whole industry would mean a steel saving of 15,000 tonnes.

Impress
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