Renaissance Men

Appropriately enough, given its origins amongst Italian artists of the 14th century, gravure is currently experiencing what might be termed as a second 'renaissance', according to secretary general of the European Rotogravure Association (ERA) James Siever. “Recent developments in cylinder engraving, prepress and within the outputting process itself have impacted positively on the cost/volume equation within the flexible packaging market,” he confirms.

The glory days when gravure enjoyed Rolls Royce status are unlikely ever to come back, of course. Likewise, the equipment is always going to be more expensive than that of the principal competition. But in terms of production cost at least, the gap is narrowing; striving to achieve comparable levels of quality reproduction, the more dominant flexo, for example, has incurred escalating expense at the front end.

“These days, gravure is not necessarily just for volume runs,” says James Siever. “I would say that the cost balance determining gravure or flexo/offset is history. Because of advances in new press technology, particularly in automation on the prepress side - galvanic and engraving lines - gravure has become far more cost efficient. There's no longer such a differential between the gravure and offset processes.

“In terms of high quality there's no real cost efficiency difference,” he emphasizes. “If anything, there are cost advantages in favour of gravure. We don't see any reason why the process shouldn't now be used for relatively shorter runs. Lengths will, of course, differ from user to user; some say 5,000m2 - others more, others less. The critical thing is that there's no definite threshold any more.

“The main advantage of gravure is its capability to ensure consistent quality over the entire run. This is not to take away from flexo, which has made significant progress as far as quality is concerned. The tricky thing is that by improving that quality, flexo has also increased its cost.

“Most gravure printers tend to also maintain flexo; choice of which process to use will largely depend on customer specification and yes, length of the overall run,” he affirms.

Market strength

Whilst gravure seems unlikely to challenge flexo's dominance in the UK, Scandinavia and North America (where the ratio of flexo to gravure is particularly pronounced at 80:20), there's a marked difference elsewhere, notes James Siever.

“If you look at central Europe, I would say that market share is more evenly distributed,” he comments. “Further afield within the developing regions: Turkey, Eastern Europe, India, the Middle East and into Asia-Pacific including China, then gravure can be up to 80 per cent of flexible packaging out and above.

“Investment for gravure is higher than flexo, but the interesting trend that's developing is the emergence of local manufacturers in some of these countries in addition to local representation of the major press suppliers. So gravure is benefiting partly through local manufacture, and also the willingness to invest with an eye to supplying gravure printed applications to the more developed markets. They're able to do this, of course, due to lower labour costs; the higher cost of prepress in gravure isn't such a significant factor as it would be in say the US, or Western Europe.”

Figures published by Pira International indicate that whilst gravure can anticipate an overall growth rate of around 2 per cent to hit $84B this year (compared with flexo running at closer to 4 per cent growth), in developing countries such as China, India and parts of Africa it's accelerating at more like 10 per cent.

Closer to home, an in depth market study conducted amongst leading global brands and converters based in Turkey and the Ukraine by independent research consultancy GfK has confirmed a willingness amongst print buyers to pay higher premiums for gravure quality, even for relatively small runs.

According to the GfK report, gravure is recognized as the primary process for flexible packaging in Turkey, where a higher price is also regarded as an indication of better quality. The rising level of demand from brand manufacturers in the Ukraine is also boosting gravure's market profile there.

Perhaps most significant of all is that the positive level of support for the process amongst survey respondents appears to pre-date awareness of many of the latest innovations in gravure technology and their positive effects on efficiency and costs viz automation in cylinder preparation and in the pressroom, as well as quicker change-over and makeready.

Advances in cylinder technology

At the heart of the process sits the rotogravure non ferrous metal coated steel cylinder. Leading supplier Hell Gravure Systems has now successfully completed an eight-year R&D programme aimed at developing a direct laser engraving process for copper coated cylinders with its Cellaxy outputting device, currently undergoing beta testing prior to commercialization later this year.

The Cellaxy is fitted with a high power multi kilowatt laser with a resolution of 2,540dpi (1,000 l/cm) that lasers cells directly into the copper surface - meanwhile, the electroplating process for producing the engraving cylinder surface remains unchanged. The laser works in continuous mode and is controlled with a 3D-Rip. The writing principle is similar to that of an offset platesetter, with each cell being formed from a matrix of 16 x 16 laser dots, for example.

However, in contrast to offset, the laser can vary the intensity, and therefore the depth, of each individual laser dot. This enables the engraving screen to be freely adjusted in terms of screen resolution, dot shape, depth, and cell-to-wall ratio: the property that will allow a printing form to be adapted to specific process conditions.

As the Cellaxy always employs a write resolution of 2,540dpi, extremely high contour definition is produced. This makes the system ideal for gravure applications in the tobacco, labelling, and pharmaceuticals sectors. It is being used initially at Dissen, Germany, based 4 Packaging for engraving full tone cylinders for cigarette applications requiring high print densities and ultra fine graphics.

Compared with flexo plates, cylinder cost in relation to the amount of usage/unit is still a high price to pay for perfection. A UK company, however, may have come up with a practical refurbishment solution in terms of extending life expectancy, as well as significantly reducing prepress time.

Liverpool based Edwards Engineering has developed a novel re-sizing process aimed at making better use of what would otherwise be written off as redundant cylinders.

“Gravure is continually under price pressure nowadays - more so than flexo, because whereas gravure has always been considered to be the quality process, I suspect that packaging buyers pay less attention to that and more so to lead time and price,” says the company's plastics consultant, Peter Williams. “It's sad but true that if you showed a typical buyer a gravure print and a flexo print they wouldn't know the difference, because they wouldn't know what they were looking at. OK, so gravure produces the finer result, but people don't necessarily want that; they want what's most expedient for their business.

“Gravure has always been the most expensive process, and has to somehow reduce its costs,” he stresses. “Over the last few years, whilst printers and engravers have steadily increased their efficiencies and looked hard at their expenditure, there really isn't a great deal more they can do to cut costs, even though the market still demands it.

“So what we've looked at is taking a redundant steel base, which is a not insignificant cost - pre-engraving, these can cost around £200 each, so an eight colour job requires an outlay of £1,600 before ink meets substrate - and have developed a patented process to put syntactic polyurethane coating by a ribbon flow technique over that base, and turn it on a lathe to a larger size than the original, so that it can be recycled.

“We can do this for a cost that's typically between 60 and 70 per cent of the new base price. Extrapolate that out to a printer who's buying say 10,000 cylinders a year, and it amounts to a considerable gain.

“Apart from the cost saving, we can also reduce lead times dramatically,” he claims. A new steel base could take seven to 10 days from order to delivery, whereas we can plastics coat, turn and send for copper engraving within four days maximum.”

In addition to its UK base, Edwards has already signed up a US licensee and is currently conducting trials in Germany. With further expansion planned worldwide, Peter Williams assesses that the potential market for re-sizing existing steel cylinders could easily run into six figures per annum.

Shorter run lengths

The 'big three' when it comes to the manufacture of gravure presses of around 1.5m width for flexibles are Cerutti, Rotomec Bobst, and Windmöller & Hölscher: collectively responsible for the bulk of the 310 plus packaging and decorative gravure application outputting systems currently installed across Europe.

Cerutti is certainly keen to dispel suppositions that gravure is limited to volume production. Targeting the need to reduce the resources necessary for running and makeready, non productive system downtimes, and waste incurred during production runs, the Italian press manufacturer is placing considerable emphasis upon its R 970 series, characterized by high flexibility and ease of use owing to a high level of automation and integrated wash-up system onboard the printing units - which can be independently pre-selected, with individual unit parts washed and replaced during job changes.

After the parts have been arranged in their relevant seats inside the printing unit, special servo mechanisms adjust the correct work position so the next job can be started with minimum material waste incurred.

An essential part of the R 970's high level of automation is a greatly simplified and dedicated trolley system facilitating single operator makeready management within about two minutes per trolley (compared with nearer to 20min, and involving an additional operative), further boosting the claims for shorter run suitability at between 15-20,000 linear metres, at a third of the previous time taken up.

Rotomec claims to hold 85 per cent of the global short run market, largely through the widespread adoption of its RS 4004 E press. First introduced in 2003, the system has demonstrated a capability to halve change-over time between jobs, as well as significantly cutting downtime for operations off the press due to its dedicated off-line washing machine, which cleans down the trolley complete with all the inking parts.

As well as the RS 4003 providing a more compact, modular extension to the same technology in 2005, Rotomec has also scored heavily with its more recently launched MW 60 (minimum wastage) gravure press.

Totally operated from floor level, the system's compact dimensions - only 22m for a 10 colour line - are matched by a 50 per cent shorter web path compared with a conventional press. Dryers are placed at an oblique angle from the printing unit - not vertical as is the norm, and claimed by Rotomec to represent an industry 'first' - with the net result of maximizing drying as well minimizing solvent retention on the web.

Providing a highly cost effective alternative particularly to web offset systems, the M 60 handles the full range of films, as well as paper and laminates. Its versatile configuration is said to suit a broad range of market segments and applications, including labels and foiling for pharmaceuticals, cosmetics and food packaging. More than 10 MW 60 lines have been installed since its launch last June.

At last year's in-house Expo in Lengerich, Windmöller & Hölscher presented a new Heliostar GS gravure station designed to use both shafted cylinders and sleeves. Featuring an established gravure sleeve system, the demonstration showed visitors how easy it is to change the sleeves on the machine, and how sleeves and shafted cylinders can be combined efficiently. The advantage of the new system is that the Heliostar GS allows for the use of existing gravure cylinders, while gradually changing to the use of sleeve technology. W&H says it is the ideal press for launching into gravure cylinder sleeve technology.

On the end use front, innovative gravure printed applications produced by Amcor Flexibles include a vertical form, fill and seal steam ventilating system for fresh produce for use in the microwave. Amcor SelfVent packs can be placed directly into the microwave without the need for piercing or tearing of the packs, also cutting cooking time by around 70 per cent compared with the conventional hob cooking method, and with the added environmental benefit of saving energy, it is claimed. The 35 micron recyclable OPP film has a special disruptor system applied in register to the pack at the same time as printing. This controls the venting of the pack when the pressure builds up during cooking.

High definition gravure printed graphics are also lending on-shelf support to Amcor Flexible's PushPop stand-up pack supplied to UK brand owner White's for a range of snacking products. It is said to be ideal either for single use or for re-closure, with the application of a pressure sensitive adhesive coated label.