The symposium entitled "Folding box production – Harnessing new growth potential with process optimization" held on 26 September as part of this year’s FachPack by the two trade journals PackReport and PackMittel in cooperation with the dfv-academy of the Deutsche Fachverlag (German Technical Press) attracted great interest. About 70 attendees followed with close attention the program of presentations which comprised four technical talks on very different aspects of modern folding box production. The Heidelberg company was a co-organizer of the event.
After a welcoming speech and introduction to the topics by the symposium facilitator Carlos Lange-Prollius, editor-in-chief of the trade journals PackReport and PackMittel, Wolfgang Suerbaum, CEO of Smurfit Kappa Carton and member of the Executive Committee of the Trade Association of the Folding Box Industry (FFI), started by giving an overview of the economic situation of the German folding box industry. In view of the 5 percent increase in sales in 2006 the mood in the sector is optimistic. Sales are also expected to rise at least in the near future.
Apart from the high qualification of employees and speed, flexibility and logistics in production, the high level of innovativeness of the manufacturers certainly makes a key contribution to this positive development. Germany is the acknowledged leader when it comes to new developments in production processes and in further processing and high quality finishing.
"Today, folding box packs must offer substantially more than functional utility," the speaker stressed. The possibilities ranged from psychological aspects ("Folding boxes can create emotional added value") through neuro-economic properties ("Brands and packaging make consumers insensitive to pain") through to thoughts on how the brain reacts to prices and brands.
Jens Niemann, applications engineer at hot and cold film producer Leonhard Kurz GmbH & Co. KG, by its own account the world’s leading company in this sector, gave a technically highly detailed presentation from the hands-on viewpoint on the subject of "Cold film transfer as a supplement to conventional hot film embossing." He began by describing the basic features of the two finishing processes and then compared advantages and processing limits.
Hot embossing versus cold film transfer
The technique of hot embossing practiced for many years in the relief printing process is usually performed offline in three variants: flat to flat, round/flat or round/round. The first of these variants is a very rugged technology with high accuracy of register which can attain rates of 7,500 sheets/per hour with no problem. The rotary methods allows even higher speeds of up to 10,000 sheets/hour, but with certain limitations with regard to accuracy of register. Embossing punches are generally necessary for all three variants.
Cold film transfer represents a combination of printing and lamination process which is normally effected online with offset printing plates but also in flexographic or letterpress printing. There are two versions, rotary processing with UV curing and sheet processing. In offset sheet printing conventionally hardening adhesives are traditionally used, with the disadvantage that further processing, especially die cutting, takes longer. The use of UV curing is under development at present. According to the assessment of the speaker, progress can be expected already in the next few months.
Classic application areas for hot embossing and cold films alike are self-adhesive and wet adhesive labels, packaging, greetings cards, magazines, calendars, posters, visiting cards and advertising articles. Jens Niemann stressed that as far as the processing result is concerned only a professional would spot the difference in the method used.
He sees the advantages of hot embossing in gloss and haptic effects among others. The finishing method can also be applied on most materials. Embossing or debossing are realized in one step with perfect register. Savings of film are also possible. The hot embossing process has limitations, for example with respect to the reproduction of half-tones and the combination of large areas with fine negatives which reduces the production speed.
A certain trend towards cold film
A crucial plus point in favor of cold film transfer is the high production speed due to inline processing and the design possibilities from full area to half-tones. No embossing punches are necessary. The printed material is not deformed, and short make-ready times and completion of changes of job within minutes also make a positive impact.
The process is subject to limitations when used for finishing absorbent print materials. A slightly lower degree of gloss of the applied film must also be tolerated depending on the surface consistency of the printed material, the print quality of the adhesive and the overlacquering, for example with matt lacquer. Film consumption can be up to 30 percent higher with offset sheet printing. Inline embossing/debossing is likewise not possible in this case.
When weighing up the pros and cons of the two finishing methods the speaker came to the conclusion that both processes have a right to exist. Hot embossing cannot be replaced by cold film transfer as a general rule. The conventional process is advisable for use chiefly for large runs, on paper or board with an absorbent surface and when haptic effects and embossed designs with perfect register accuracy are required. Cold film transfer is recommended for small and medium-long runs up to 5,000 sheets/hour on materials with only low temperature stability. It can be used for creating specific color tones and innovative metallic print color effects with high gloss.
Jens Niemann summed as follows: "Cold film transfer does not replace the hot embossing process but supplements it. The cold film technique offers new finishing options and expands the range of applications for metallized films."
Technical advances in the cutting and grooving of folding boxes was explained by Klaus Linhardt, CEO of Karl Linhardt Stanzformen GmbH. His emphasis was on the so-called cutting and grooving technique. This method of making grooving devices which is the main rival of groove die milling is only a few years old. Up until about 15 years ago the use of counterplates was very restricted due to production technique using electric discharge machining and because of the resulting high costs.
This mid-sized manufacturer which specializes in the production of flat dies was the first to begin in 1992 with the production of milled steel counterplates on a machine of its own design. In the period that followed, increasing market acceptance was observable. More than 50% of all grooving devices produced by Linhardt are of the steel counterplate type and the trend is upwards.
According to the speaker, there are several reasons for the use of a milled steel counterplate as an alternative to a grooving die; for example improved machine performance, reduced tensile forces due to smoother sheet travel, flat blanks and uniform quality of the grooves. Also reprints are avoided, counterscoring lines and embossing punches are easy to integrate and there is a smaller number of holding points.
Depending on the application there are in practice two plates of different hardness (35 or 50 HRC) available for use. In the case of the 35 HRC plate a life of 1 million sheets can be taken as an assumption and with the fully hardened version as many as 3 to 4 million die cutting operations. To complete the range there is also a soft version with 15 HRC.
Successful technology partnership
Last but not least, Karl-Heinz Freund, the managing partner of the corrugated board, carton packaging and display manufacturer Friedrich Freund GmbH, reported on experiences of nearly a decade of technology partnership between his company and printing machine manufacturer Heidelberg. This dated back to the decision to change over production at the Krefeld location from sheet format VI to III B, and the purchase in this connection of a Speedmaster CD 102-6+L. Cooperation intensified over the following period not least due to the expansion of the Heidelberg Group through the addition of a sheet die cutting machine manufacturer and a producer of folding box gluing machines. True to the maxim "everything from a single source" a second Speedmaster CD 102-6+L, a Diana Pro 74 folding box gluing line and 2 Dymatrix 106 CSB die cutting machines were acquired in 2004 among other investments, after the idea of converting from sheet offset to flexographic printing which was considered briefly had been rejected again.
As early as 1999 a first step was taken towards networking the workflow by supplying the printing machine with CIP 3 data via Prinect Data Control. Starting in 2004 the IT network was expanded under the lead management of Heidelberg. In the following year the ERP system Boxsoft was installed and in 2006 Prinect Data Control based on JDF was partially integrated. Further expansion of the JDF workflow is planned in the future.
By Bernd Neumann, freelance employee at PackMittel, Leverkusen.
Bildunterschriften:
The speakers at the dfv Symposium "Folding box production" (from the left): Wolfgang Suerbaum, CEO Smurfit Kappa Carton and member of the Executive Committee of FFI, Jens Niemann, Technical Engineer Graphics (Leonhard Kurz), Karl-Heinz Freund, managing partner of Friedrich Freund GmbH and Klaus Linhardt (Karl Linhardt Stanzformen). Steel counterplate with milling for embossing punches.
Packmittel, 14.12.2007, page 026