Tag Archives: Can Performance

Market Research

Doing market research when you’re in the business of making cans often amounts to visiting the supermarket and seeing what’s on the shelves. I remember going to Florida on holiday and bringing back a shaped juice can as well as a quart can of Fosters. Good information to get some ideas for shaped cans and larger than standard size drinks cans.

Also, when I visited Japan when in Ebbw Vale, I brought back some TULC cans, in the hope that this might be of assistance with the development of the rBS can.

Sometimes the places of research are more pedestrian, like when I wanted to investigated the can performance characteristics of Impress’s 2-12-2 bead pattern on their food cans: all I had to do was scan the shelves in my local Asda store, and once I had located their cans on an own brand soup make buy a crate full of them. All I had to do was to ask people at work to take the cans home, use the contents, and return the empty cans in a state suitable for further investigation of the can properties. Cheap and easy, even though I had to endure a sarky “on a liquid diet, aren’t we?” from the till operator.

Sometimes this supermarket research could have some unintended consequences, such as when Chris Elliot and Tim Fields spent such a long time in the aerosol can section of one supermarket that Security was called to investigate this “suspicious” behaviour. Still, I can’t think of another field where it’s so cheap and easy to examine a competitor’s product in attempts to reverse engineer them.

rBS Can

an rBS can, still in good shape after nearly 20 yearsThe rBS (or redicon / British Steel) Can was an attempt to produce the equivalent of the Japanese TULC can, using Ferrolite1 as its feedstock. The Ferrolite process in Trostre took a coil of ECCS (electro-coated chromium steel, or steel coated with a chrome-chrome oxide layer, also called TFS, or tin-free steel) substrate and fed it into contact on both sides of the strip with a film of usually polypropylene or PET. That way you can make aerosol cans or food cans which is in essence a coated product.

The only problem being that you can’t weld Ferrolite, at least not with your standard Soudronic welder. For starters, and unlike the tin coating of standard Tinplate, the chrome oxide of TFS does not conduct electricity well, and neither does it melt the way tin does. So you either prepare the welded edge by removing the coating (in which case you have to apply a protective coating of the bare edge after welding the can) or you have to make your can without any welding by using the DRD (draw-redraw) process or a similar drawing process.

The rBS can was one step beyond the DRD process, with drawing ratios more akin to that of the DWI (draw and wall-ironed) process, which first of all was a challenge to the integrity of the Ferrolite coating, but raised issues with lubrication. When you draw and iron a Tinplate DWI can, the tin acts as a lubricant and the lubrication fluid is there more in the capacity of a coolant rather than contributing much to the actual lubrication.

Clearly this is totally different for a Ferrolite feedstock, where the substrate does not contribute to the lubrication process at all, hence the lubricant really has to do the job of lubricating the process and carrying away the excess heat. The latter is especially important since otherwise the PET coating could easily start showing micro-cracks which would, when filled with liquid, lead to rapid corrosion of the underlying steel substrate and spoilage of the drink.

In short, that’s really what happened anyway: it proved possible to produce a can, which when left to its own devices was corrosion resistant when exposed to the atmosphere. However, the PET coating, which initially proved to be intact, started to exhibit micro-cracks after subsequent heating cycles (the latter simulating preparation of the can prior to filling). Brian Bastable, who was our Ferrolite expert, brought this major flaw to the attention of David Jones, who decided to go ahead anyway.

It even went as far as trials in China, where John S Williams, head of the PACS Centre, went to oversee the production of trial batches in Shanghai. And then fate stepped in, in the form of a Japanese company who bought up the company where we were doing the trials, and immediately stopped any further developments in favour of adopting the well-established TULC can.

Opportunity missed, or saved by the bell ? I suppose we’ll never know, because after that the rBS can died a quiet death, and as far as I’m aware we aimed our subsequent efforts on 2-piece aerosol cans, where a drawn can body would replace the welded can body cum domed bottom piece of steel aerosol cans.

But that’s a different story. Meanwhile, I still have an rBS can in my possession, which I have used over the years as a pen holder at work. The smudges you can see are just plain dirt from being handled in a mucky environment, but it’s still free of any rust, unlike a DRD can that I had retained but discarded once it was too rusty.

However, I suppose we’ll never known how it would have held up to containing aggressive drinks such as cola or mineral water.

(1) From “Canmaking: The Technology of Metal Protection and Decoration”, p.129
T.A. Turner, Crown Cork & Seal, Wantage, UK
Springer Science + Business Media, LLC – 1998

The first lamination line of this type was installed by Metal Box in their Neath (South Wales, UK) factory in 1985 and ran at speeds of up to 65-70 m/min, depending on steel gauge and the laminate structure being manufactured. A second line was installed by British Steel Tinplate in their Trostre plant (South Wales, UK) two years later, based on technology licensed from Metal Box.

Ferrolite has been converted, on a commercial basis, into a variety of products, for example aerosol components (cones, domes and valve-cups), easy-open ends and drawn containers for food.

Hand Beader

At Tinplate R&D we used to have a hand beader on loan from Impress. Before I continue I should explain what beads signify in connection with food cans: they’re the sort of ribs you see indenting the cylindrical body of a food can. Their main function is to give the can body some degree of rigidity when it goes through the heating and cooling cycle when the food is being cooked inside the can. We did have an MB80 industrial beader to give our cans a standard bead, but if you want to investigate the effect of different bead geometries on the can properties, then you need to have a process where you can apply a variety of geometries rather than one standard one. That’s where the hand beader comes in.

Anyhow, to get on with the story, at some stage Impress said they wanted the hand beader returned, which left us without the means to implement our research programme just as we were about to launch into a extended study of how different bead profiles affected the can properties. Fortunately we had the drawings, and knew what needed to be done to produce a copy of the machine that had gone walkies.

The only thing we now had to overcome was the inertia of the British Steel ordering system, where the concept of approved suppliers had been introduced fairly recently, and which could have set us back several months unless we managed to find a back door solution. A good thing that Norman Leah knew of a small workshop in Ammanford which was an the approved supplier list, and was in the line of work that could supply us with most of the framework. Somehow along the line I had the impression that Norman might know the person in charge and was pushing him some jobs whenever he could as a favour.

Still, that was only a vague impression, and if it helped speed up the project, who was I to complain or dig any deeper for possible ulterior motives. Another way of getting things done quickly was to buy standard parts with cash, which could then be reclaimed from expenses. Anything to avoid going through a system of getting three approved suppliers, get a quote from each of them, and then leave it up the purchase department to come up with a decision, which might or might not take several weeks.

In the end we managed to have the hand beader rebuilt in about a month, from the moment the original one was returned until the moment that we had a fully working replacement. Basically it put our research programme back on track with only a minor delay, whereas it could otherwise easily have been derailed. It was a very satisfying moment, a rare occurrence during my time when I worked for David Jones.