Smurfit Kappa Lübbecke believes it has has taken the lead in the area of offset lamination with the first installation in Germany of a Foliostar 165 Matic sheet-to-sheet laminator from Bobst Asitrade.

“In industries such as food and electronics, discount market suppliers are attaching increasing importance to print quality. This is, for example, the case for POS materials such as displays or retail-ready packaging,” says Olaf Kuhlmann, manager of Smurfit Kappa corrugated board plant, describing the trend in the market. This opens a vast field for offset lamination. “We are expecting steady growth in this area,” says Kuhlmann. Which explains why the plant’s capacities were massively expanded in this area in the autumn of 2010.

Since the demands of the market could no longer be met with the existing laminating machine, the decision was made to install Germany’s first sheet-to-sheet laminator in the corrugated board industry. In mid-September 2010, the high-performance machine was delivered and was set up within three weeks. Just one month later, series production began.

Capacity almost doubled

With the Foliostar 165 Matic, Smurfit Kappa Lübbecke has almost doubled its annual capacity in offset lamination. “Taking into account machine stops and setting-up times, our hourly output in the area of sheet lamination used to be around 2,000 m2. Currently, we achieve 3,000-3,500 m2,” says Kuhlmann, quantifying the difference in daily production. This 50-60 percent gain in productivity has several reasons: Firstly, with a production rate of up to 9,000 sheets per hour, the machine offers a much higher throughput than the previous one. Secondly, “the Foliostar 165 Matic sheet-to-sheet laminator has allowed us to fully automate additional work steps as well as the transportation of sheets to the cutter. “In addition, the technology is said to guarantee high production stability and reliability.

The higher level of automation starts with the setting up of the machine. The machine operators enter the formats of the printing and substrate sheets (up to 1,650 x 1,650mm) on the touch screen of the Matic S3 control. The dimensions of the print and carrier sheets are then determined electronically and recorded in the Matic control via the touch screen. In the next step, the self-setting system uses 17 servo motors to automatically set up the machine. If necessary, all parameters can be fine-tuned during production via the touch screen of the control unit.

Three minutes set up

All this has reduced setting up times from around 15 to 18 minutes in the past to just ten to 12 minutes today. Mr. Kuhlmann explains: “There is also a trend towards lower production volumes in the area of consumer packaging. The more frequently we change jobs, the greater our time saving.” In general, five to 10 lamination jobs are performed each day in Lübbecke. On some days, however, even more orders are processed with the Foliostar 165 Matic. The production volumes vary from a few hundred sheets for items such as special displays, to tens of thousands of sheets for series products. Many of these jobs are repeat orders and are stored in the Matic control unit. When needed, they can be retrieved at any time. For this type of order, setting up times can be as fast as around three minutes.

 Usually, the plant processes sheets with an area density of 160 to 230 g/m2. They are delivered on pallets and automatically fed into the machine via the newly developed sheet feeder with continuous height adjustment of the feeder platform. Side feelers automatically centre the stack on the lifting plate. All the machine operator then needs to do is press a button and the lifting plate is automatically moved up to the suction head. The feeder is also automatically adjusted to the correct format length without any need for manual intervention. Finally, the belts and guide rollers of the feeder transport the sheets in an overlapping manner via the conveyor bridge to the laminating unit.

At the moment, the carrier sheets are still loaded manually. “Asitrade is working on a special pre-feeder that will allow us to load the sheets automatically in the future,” says Kuhlmann, looking ahead. Automating this step only makes sense if all manual intervention can be eliminated, not just during the feeding process but also when pallets need changing. Otherwise, the machine would have to be stopped each time a pallet needs changing, thus reducing the productivity of the process, in particular in the case of larger flutes.

Flexibility of flutes

The automated feeder with vacuum belts for the carrier sheets ensures that the different types of corrugated board are reliably fed into the machine – in the Lübbecke plant the focus is on laminating EE and FE corrugated boards (German classification for thin/very thin flutes). But here too the company is now flexible and open to new challenges. Kuhlmann explains: “If necessary, we can laminate all types of corrugated board with the Foliostar 165.” Regardless of whether single-sided small and large flutes, or full-area substrates such as double-sided corrugated board with thicknesses of up to 10mm, are to be laminated – via the Matic control the feed rollers automatically adjust the size and side guides on both sides.

After the sheets of corrugated board have been fed into the machine, they are transported to the gluing unit, which has also been designed for maximum precision and is capable of applying extremely thin layers of glue. Excellent results can thus also be achieved if glue is to be applied over the entire area of a linerboard. Depending on the requirements, the sheets can thus be moved in both directions in the plant, either as a lying or standing flute.

A foamer has been integrated in the process that ‘extends’ the PVA glue with a compressed air content of 40 percent. As a result, less moisture is introduced to the process through the glue medium. This helps the sheets to remain flat. Furthermore, the plant operators have been able to halve the standstill/drying time required between the lamination process and the following steps to just twelve hours. As a result, they can now plan the process more flexibly and process customer orders faster, not to mention the reduced glue consumption of up to 20 percent, depending on the type of flute, with reduced costs.

Correct lamination

After the carrier sheets leave the gluing unit, they are transported to the laminating unit while the printed sheets are transported from the top, via a ramp, to the laminating point. This merging process is timed with such precision that the sheets lie perfectly on top of each other despite the high speed. Whereas in the past the laminating tolerance used to be between one and three millimetres, today Smurfit Kappa Lübbecke produces within a maximum tolerance of ± 0.5 mm.

After the laminating unit, the sheets are transported to a single-press line, something that had previously only been associated with inline lamination machines. The single press line improves the adhesion of the printing sheets to the carrier sheets and reduces glue consumption. In addition, the sheets can later be stacked more rapidly in an overlapping manner and transported reliably via a non-stop carpet to the feeder.

   Thanks to the increased stability, precise gluing and reliability of the laminating process, waste is considerably reduced. When starting a new job, the operator can run a sample process during which just one sheet is laminated. This allo
ws the operator to check all the production parameters. According to Kuhlmann: “The fact that the machine is set up so quickly means we have little start-up waste.”

Higher cutting standards

The lion’s share of the laminated sheets is automatically transported from the feeder to the Mastercut 1.7 flat-bed die cutter. The need to use forklift trucks in sheet-to-sheet lamination to transport sheets to and from the machine is almost eliminated, thus making the process safer for employees.

The Mastercut 1.7 was installed at the end of 2010. In a way, it represents the icing on the cake. According to Kuhlmann: “The two investments go hand in hand. Otherwise, we would have shifted the bottleneck to the cutter.” One of the highlights of the cutter is the Power Register System (PRS) that utilises highly sensitive cameras to detect either the sheet edges or specially printed register marks. Based on the information read, the sheets are aligned in exact register with the cutters. The result is an extremely accurate print-cut register.

Only around 10-15 percent of the laminated sheets are stacked on pallets. These are jobs that involve sheets that are only laminated in the Lübbecke plant before being transported to sister plants or other customers for further processing.

There have therefore been a number of key changes in the laminating process, “which we carefully evaluated in our calculation of profitability in terms of a rapid amortisation,” emphasises Kuhlmann. Then there are also soft facts, such as increased flexibility, which is very important to customers and also regarding competition with other suppliers, but ultimately cannot really be evaluated in monetary terms.

BOBST/ASITRADE:

T: +41 21 621 21 11

E: francoise.rosselet@bobstgroup.com