Corrugated board plant

from Wikipedia, the free encyclopedia

A corrugated board plant consists of individual machines that produce individual sheets of corrugated board from rolls of paper . The approx. 120 m long system is roughly divided into wet and dry ends. The width is up to 5 m, whereby this is based on the working width, i.e. the width of the paper rolls to be processed.

Wet end

Dispenser

On the dispenser, the paper rolls are picked up between two arms equipped with dispensing mandrels. Automatic versions can automatically detect and pick up the sleeve with the help of laser sensors. The design of the dispenser is always such that two rolls can be accommodated. As a result, at the end of the first roll, the second can be spliced ​​in order to continue production.

Splicer

The splicer is located above the dispensers and is necessary to keep the system running continuously. When a paper roll is used up, the end of the roll is spliced ​​together with the beginning of the new roll in the splicer. A particularly strong double-sided adhesive tape is used for this.

For the splicing process, the paper web is braked and fixed by a brake bar in the splice head. Then the piece of the new roll prepared with the adhesive tape is glued onto it. At this moment the paper web must come to a standstill. In order to compensate for this standstill, the splicer has a roller system, also known as a storage or dancer carriage, in which paper is stored that is used in the splicing process. While the production speed for the splicing process often had to be reduced with older models, this process can be carried out at almost any speed with modern splicers.

One-sided machine

The single facer is the heart of the system. Two paper webs are processed there. One is corrugated between two steam-heated corrugated rollers into the shape typical of corrugated cardboard. Then the corrugation tips are coated with glue on the integrated gluing unit and glued under the press roller with a smooth cover sheet. The one-sided cardboard web that is created in this way is transported to the bridge using belts.

Triple preheater

The preheater consists of heated drums or heating plates standing on top of one another. Here the one-sided strips and the last lamination strip are warmed up again before they are glued. This warming up is important for the bonding process from a procedural point of view. In order to change the heat absorption of the tracks on the cylinder, the contact surface can be adjusted with the help of wrap arms. By changing the heat absorption, the flatness of the corrugated cardboard formats produced can be influenced at the same time.

Laminating glue plant

The gluing unit consists of individual modules - one for each one-sided strip - and wets the shaft tips with glue for the subsequent gluing process. To do this, a rotating glue application roller is dipped into the adhesive. To apply the glue, the application roller is brought into brief contact with the one-sided web that is passing by. The uneven adhesive film picked up is smoothed out by a squeegee roller or a rotating doctor blade .

Pulling and heating section

The draft and heating section is one of the most noticeable - because it is longest - parts of the system. It consists of two areas, the heating section and the train section. In the inlet to the heating section, the individual one-sided sheets and the lamination sheet are brought together to be glued together there. For this purpose, the individual strips are drawn over steam-heated heating plates and at the same time pressed on from above using rollers, metal shoes or other systems. This allows the heat to penetrate the material and dry the adhesive as well as evaporate moisture, which gives the cardboard additional strength.

Occasionally the drawing and heating section is also counted towards the end of the drying period, because this is where the transition from moist to dry cardboard takes place.

The following train section only serves to transport the cardboard. In addition to the upper strap, there is a lower strap. Wedged between these two belts, the web is pulled from the bridge and pushed into the other machines at the drying end.

End of drying

Short sheeter

The short sheeter can cut the web across the running direction and thus fulfills two tasks. On the one hand, it cuts out unusable areas from the running web. In addition, by separating the web and at the same time accelerating the leading web section, a gap can be created that is required for tool adjustment in the subsequent automatic cutting and creasing machine. The cut is made using two knives screwed onto a knife bar in a spiral.

Automatic cutting and creasing machine

The automatic cutting and creasing machine consists of individual cutting and creasing modules. The number of modules adapts to the requirements of the desired orders, as each module can only have a certain number of tools. In the cutting module, the paper web is divided lengthways into individual webs, so-called panels, by rotating circular knives. The tools in the creasing module work in a similar way, but there the cardboard is only squeezed in order to obtain a folded edge when the corrugated cardboard is to be processed into folding boxes.

Sheeter

Like the short cross cutter, the cross cutter also has cutter bars on which knives are screwed in a spiral. The aim is to cut the panels crosswise in order to cut the webs into individual sheets of a defined length.

Filing

The last machine in the corrugator is the tray on which the individual sheets are collected in stacks. These then leave the tray on the side via conveyor belts and are ready for further processing (printing, punching, folding, gluing) into the finished box.

Steam and condensate system

In addition to the basic materials paper and adhesive, water vapor is an important component in corrugated cardboard production. It is used to heat the heating plates in the heating section, the preheater drums or plates as well as the corrugating and press rollers in the single-sided machine. The temperature of the condensate is usually approx. 170 - 200 ° C. The paper temperature is between 80 and 110 ° C, depending on the design of the system and the type of corrugated cardboard. The pressure of the steam also plays an important role; in modern systems it is 15 bar and higher.

Trivia

  • The production world record has been held by a system in Ebersdorf near Coburg since December 23, 2014 with an average of 376 m / min and a length of approx. 180,600 m in 8 hours. Almost the same performance was achieved by a corrugator in Amposta, Spain, which, according to the company, achieved an average of over 370 m / min over eight hours.
  • According to the company, the record for the highest production speed ever achieved is held by a system in Ebersdorf with over 450 m / min.
  • The record for the largest production width (3350 mm) is shared by two systems, one in Wörth am Rhein , the other in Offenbach an der Queich.
  • The German BHS Corrugated is currently the only machine supplier that can produce systems in working widths of 3300 mm or 3350 mm.

Manufacturers

Since a relatively large number of consumers can be reached with a modern corrugator (approx. 100 km around the production site), only a few companies worldwide have established themselves in the development and sale of corrugated board systems. Here is a selection of the most important: