Various configurations for extra-long Rapida sheetfed offset presses

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The Rapida 106 X sets international benchmarks in terms of production speed and make-ready time: a long finishing press from this series is available at Koenig & Bauer’s CEC to test the latest process trends, including incorporation of additional printing units after varnishing.

A look into the final assembly hall at Koenig & Bauer leaves no doubt: Rapida sheetfed offset presses, especially those in 3b format, are once again configured with an increasing number of printing units and finishing. It is possible to marvel at combinations of printing, coating and drying units that would have been unthinkable in this form just a few years ago. All of these presses respond to the trend towards ever greater product sophistication in the packaging industry. At the same time, there is growing pressure to deliver complex press solutions capable of printing exactly these kinds of highly finished products in a cost-effective process. Another goal in many cases is to use the printed and finished cartons as environmentally friendly primary packaging and eliminate the need for additional plastic film materials.

This trend has already become evident among printing companies that have been producing cigarette packaging for a few years now. In the past, Koenig & Bauer has supplied sheetfed offset presses with 17, 18 or even 19 printing and finishing units and total lengths of up to 35 meters for these special applications. And now, other segments of the industry are also recognizing the economic need for individually configured long presses capable of handling a wide range of in-line product finishes. Here is an overview of the possibilities:

1. Straight presses with coating before and after coating in combination with cold foil application

This technology is used to produce packaging for pharmaceuticals, cosmetics and cigarettes, for example. Characteristic of these presses is the coater and two intermediate drying units immediately after the feeder and the infeed. They are followed by a large number of printing units, the first of which (two) are frequently used to apply cold foil (Figure 1). With the ability to print multiple spot colors or similarly print with six or seven process colors to extend the range of colors available, the number of print units can easily exceed the magic number of ten. . The printing units are followed by further coaters and a corresponding number of intermediate drying units, before a delivery extended by three lengths (3.8 meters).

Rapida 106 X with 17 printing and finishing units: pre- and post-print coating facilities.

Totals of 17 to 19 printing units are currently “standard” for presses like this. They are used in a number of central European industrial countries, but also in areas where few people would expect to find such complex presses. And they have long ceased to be one-time installations. Their number is steadily increasing. After all, these Rapida presses not only offer the ability to combine printing with high-quality and extremely versatile in-line finishing (including multiple UV coatings), but also do so at above-average production speeds that can still reach 15,000 sheets per hour. The equipment package usually includes logistics solutions and a selection of anilox rolls for different thicknesses and types of coating. With the AniloxLoader of the Rapida 106 X, anilox rolls are replaced fully automatically in no time. DriveTronic SFC, moreover, enables changing coating forms in less than a minute, parallel to other make-ready processes on the press.

2. Straight presses with printing units after coating

These presses are frequently chosen by producers of packaging for the food industry (and in particular for bakery and confectionery products), but are also used in the general packaging segment, for cosmetics and personal care products. , household items and pet supplies. They are the ideal means of production for folding boxes, sleeves and highly finished packaging: on the one hand to protect the product, and on the other hand for an optimal presentation.

The eight to ten printing units are followed by a coater, an intermediate dryer, another printing unit and sometimes a second coater (Figure 2). This allows, for example, full coating in the first coater and then the application of a spot matt coating by means of the additional printing unit – with registration in offset quality and cost-effective, as no photopolymer plate is not necessary. Another advantage of this type of coating is the reliable avoidance of unsightly fringing around the coated areas. Drip special effects are also simple to produce. If a classic double coating process is required (e.g. for metallic or haptic coatings), the printing unit can be disengaged from the production process at the push of a button and the second coater used instead.

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Post-varnish printing units enable precise and cost-effective matt varnish effects.

Another possibility is to prepare a currently unused coater for the next job while production is still in progress on the rest of the press, to minimize makeready time when the next job is changed.

Depending on the equipment options, the degree of product finish and the substrates used, these presses – which can reach a length of 30 meters with their 13 units, a triple-length extended outlet, raised foundations and an additional gallery – run at speeds of up to 18,000 or even 20,000 sheets per hour. It almost goes without saying that they often include a complete set of accessories for UV finishing.

3. Perfecting presses with printing and varnish units before and after the perfecting unit

This press configuration is also aimed at producers of packaging for the cosmetics and confectionery industries. And in this case among brand owners in particular. The classic perfector press prints one or two colors before the perfecting unit, such as a recipe or product instructions on what will later become the inside of the package. This is followed by coating, drying and turning the sheet. The image of the reverse side of the sheet – later the outside of the slipcase or folding box – is then printed in high color and with a single or multi-layer finish to achieve interesting matt/gloss or haptic effects and draw attention to the point of sale (Figure 3). Additional packages are intended for the processing of metallized panels and plastic films. The inclusion of cold foil systems with different levels of automation is also possible.

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Inverting presses with printing and varnishing units before and after the inverting unit add finishes that enhance the attractiveness of folding cartons at the point of sale.

These reversing presses can thus include 13 to 16 printing and finishing units, and also reach an overall length of 30 meters. The improvement unit is generally incorporated after the fifth or sixth unit. A variety of drying technologies are possible, including dispersion coating systems on the inside and UV coatings on the outside of the finished board. Operating speeds of up to 18,000 sheets per hour are achieved, depending on the substrate, the image to be printed and the processing medium used. Automation functions for fast job changes (simultaneous plate and coating shape change, AniloxLoader, CleanTronic Synchro) are examples of other efficiency-enhancing components. Application-specific logistics variants for fully automatic stack handling are also worth mentioning. All this means that the press is very productive both for very long runs and when frequent job changeovers are required.

4. Perfector presses with multi-coating on the front of the sheet followed by printing and coating on the back

Two or even three coaters with corresponding drying facilities, a turning unit, then the required number of printing units, followed by one or two more coaters – this is the ultimate configuration for in-line product finishing in sheetfed offset (Figure 4). These presses illustrate it well: printing presses are also coating machines. After all, one of the purposes of such applications is to produce a coating that prevents moisture absorption or makes the panel resistant to other substances (e.g. greases) so that it retains its shape and rigidity. . At the same time, the coating layers prevent migration of board or ink constituents into the packaged food or drink.

Perfecting presses with multiple coating on the front of the sheet, then printing and coating on the back: in addition to printing and finishing, these presses add coatings capable of modifying the properties of a board.

In combination with suitable cardboard and paper products, or types of laminated cardboard and other materials that are perfectly suitable for direct contact with food, these presses make it possible to produce a wide range of different articles very economically: Packaging for frozen products , cake boxes, trays and cups, packaging and trays for quality desserts, craft papers as outer and presentation packaging, snack boxes such as those used by fast food chains, stackable boxes and trays for catering companies or pizza boxes, to name just a few examples.

Presses in this category incorporate more coating and drying units than printing units. Comprehensive process know-how and many years of experience are also crucial when using these special technologies.

Ultra-long packaging press with 17 printing and finishing units in Koenig & Bauer’s final assembly hall.

Extreme specialization for profitable production

The four trends indicate the possibilities for specialization in a certain product range within the packaging industry, as the basis for profitable and future-oriented production in this area. Like many other packaging machines, sheetfed offset presses are increasingly tailored to a specific end product.

Six, seven and eight color presses, with single or double coated applications, still dominate the packaging market today and although their era looks set to continue for the foreseeable future, everyone should be aware that the trend for high complexity, individually customized printing presses is gaining momentum.

Koenig & Bauer is well positioned for this development, both in the 3b segment and in large format. With cutting-edge Rapida technologies that set global standards for production speed, high-speed makeready and process automation, and lead the packaging market.

Source: Koenig & Bauer AG

The preceding press release was provided by a company not affiliated with Print impressions. The views expressed herein do not directly reflect the thoughts or opinions of the staff of Print impressions.

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