The Buck Stops

Published: March 01, 2002, By Teresa Koltzenburg, Senior Editor

We've all been hearing about how web-fed, in-line folding carton production will bring revolutionary growth to narrow web flexo. But we're not quite there yet, says Martin White. The flexo expert explores why sheet-fed litho may be where… THE BUCK STOPS

SINGLE-LINE, ONE-PASS CARTONBOARD PRODUCTION! What happened? That's the question European flexo expert Martin White explores. In this article PFFC offers his take on the subject.

“Much has been written over the last couple of years about the development of in-line cartonboard production for narrow web presses,” White reports. “Repeatedly, this area's been forecast to revolutionize flexo growth. But, quite clearly, this has not come about.”

White examines a few of the reasons for the delayed take-off of what he calls, “surely a natural progression in cartonboard packaging.”

A Different Culture
According to White, it's fairly common for narrow web press manufacturers to put forward very convincing reasons why roll-fed production of folding cartons is infinitely more cost-effective than a sheet-fed operation. “The figures do make sense.”

“Yet,” White believes, “the logical step forward for the production of cartons — whereby the carton is perfected in one single pass — has not moved ahead [at the rate predicted].”

Why? Whites offers one possible reason: “The market for cartons in relation to flexo is relatively new. Produced from the roll, the board may be single- or multi-ply and may be folding boxboard, white-lined chipboard, solid bleached board, and solid unbleached board. StoraEnso, Iggesund, and M-Real are among the top suppliers for solid bleached boards. Production capacity for all paperboards in Europe — including those made from secondary fiber — is some seven million tonnes.”

Stateside, Westvaco says it has a substrate ideal for high-performance graphics and packaging applications. Designated “Crescendo,” the folding carton material is a one-side-coated SBS (solid bleached sulfate) board available from the company's Packaging Resource Group.

White reports it isn't possible to provide statistics regarding flexo's consumption. “Many figures are given for the annual growth of flexo in this market, but an educated guess would be 18 percent per annum.”

“But,” he cautions, “this has to be tempered by the fact that this growth is from a very low base. MTI [Market Tracking Intl.] provides a breakdown for packaging worldwide: litho — 45 percent; flexo — 28 percent; gravure — 20 percent; and others — 7 percent.”

MTI identifies the European breakdown as follows: litho — 80% and reducing; flexo — 4% and increasing; gravure — 16%. Says White, “The MTI report shows a very positive swing from litho to flexo.”

Most presses in this market are narrow web, with fewer medium-sized presses at the moment, according to White.

“There are about 12 flexo presses converting cartonboard in the U.K., using both water-based and [ultraviolet] inks; few would argue there's very little difference in the quality of water-based or UV inks [when examining the best from both categories]. Those printers converting on anything above a narrow web press are doing so roll-to-roll and die-cutting off-line.”

Positive Aspects
The development of multi-substrate flexo has created an alternative, White says. Now, cartonboards can be produced from the roll by narrow- or medium-width flexo presses (as opposed to sheet fed litho). However, he adds, “the 1998 announcement touting a ‘new’ flexo era has not shown the fast-growing movement predicted at the time.

“One of the main reasons for this [lies in the fact] cartonboard production was [and still is] mainly in the domain of the litho process. While litho printers accepted the cost savings of in-line production, it's clear they weren't ready for such a radical change in craft skills.”

While flexo printers weren't acquainted with cartonboard production to any great degree, the narrow web flexo printers' change from labels, or even flexible packaging, to a substantially more solid substrate has ushered in a new culture, White believes. “Of course, there are always exceptions; there are a few flexo companies that remain dedicated cartonboard converters and are able to produce award-winning print as good as litho.”

Although today's flexo-printed cartons' overall quality is comparable to cartons produced by other processes, White forecasts, “It will be flexo's ability to convert in-line that will ensure its future growth in this market.”

Reel Savings
According to White, brand owners — who are buying on a global basis — are forcing printers to drive their costs down. “In order for flexo to compete, printers first have to examine today's problems: decreasing run lengths; shorter response times; inefficiency of short runs on older equipment; and the expensive prospect of new machinery/technology investment. In short, prices are driven down by packers and brand owners in a position to purchase from developing countries (where environmental issues and cost structures are not comparable to those in developed nations). Decreasing costs provide the only real option.”

But what are the economics of in-line cartonboard production? White says they include: lower material costs (converting from the roll [reel]); fewer separate operations; less manpower (see table above); shorter makeready times; less waste; less production space; reduced work in progress; and lower capital investment.

On the last point, White explains that a narrow web UV press suitable for carton production costs less than a six-color, 1,020×720-mm sheet-fed press with coater. “The web press takes the place of separate operations for foil blocking, cutting and creasing, and the hand stripping department. It needs far fewer people to operate it; therefore, the hourly rate is less.” Consequently, White adds, the in-line web operation requires less floor space, so less space is required for work in progress.

Says White, “Buying roll substrates is less expensive, and there's only one variable dimension for a given grade of material: the web width — as most flexo presses provide an infinitely variable print length.”

This, he adds, enables a reduction in stock levels, and “when printing in-line from the web, there are fewer separate operations, and all the following can be completed in one pass: print on the face; print on the reverse; foil block; varnish; laminate; die-cut; and stack and pack.”

White believes even though the actual printing time is shorter in a sheet-fed operation (the sheet-fed operation will be printing from a larger plate — step and repeat), this won't provide significant savings if short to medium runs are required for “just-in-time” situations.

“Print decks not in use can be made ready while the press is running; most wash-up occurs off press; slide-in rotary die cassettes take around five minutes to change; a plate roll can be changed in less than two minutes; smaller format means easier handling of tooling.”

White's Final Analysis
While short-run, just-in-time production is necessary, a narrow web printing operation will find it wise to invest in operator training to give flexo operators greater knowledge of solid cartonboard production, says White. He also believes litho operators should study the nuances of flexo.

“Until such time as wider web flexo production is able to incorporate in-line die-cutting economically, narrow web long runs will remain in the domain of litho.”