Paper bag manufacture with Masterdrives MC

Icoma FSB, Germany
Bags and no end


They don’t have to be beautiful, just durable, sturdy and inexpensive: paper sacks. The international company Korsnäs-Wilhelmstal, with production sites in Germany, Italy, the UK, Scandinavia, Croatia and the Ukraine, specializes in the manufacture of paper sacks. At the German site in Achern, the local company Icoma FSB, which specializes in the construction of production plants within the Korsnäs Group, has built and commissioned a sack folding system which breaks all previous production records.

Paper sacks which can consist of up to six layers are used in many very different areas of daily life. Food, construction materials, animal feed, basic materials for the chemical industry and many other items used every day are packed and transported in them. At Korsnäs in Achern alone, 120 million paper sacks roll off the conveyor belt every year. The new Icoma FSB folding system enables Korsnäs to produce 250 sacks per minute – its fastest production rate ever. This is possible due to the replacement of the conventional mechanical line shafts and gears with 19 Simovert Masterdrives MC servo drives. They ensure electronically coordinated folding, adhesion and sealing of the paper sacks.

The IFM 45/130 folding system

After the printed paper has been processed from large roles into paper tubes in the desired format, the folding system then turns the tube into sacks. In order to ensure that the sacks are then stable and thick enough for their future uses, several processes such as corner sealing, edge-trimming, base welding, base gluing and base folding may be required. These work processes first require the paper tube to be rotated by 90°, as it leaves the tube machine lengthways but must run crossways through the folding system. At a high production speed, this is an important yet difficult task that the turntable on the IFM 45/130 handles with no trouble at all.

A transfer station transports the tubes to the alignment station where the tubes are brought together in exactly equal distances and the glued edge is aligned to the machine axle. At a conveyor belt speed reduced by around 40%, the future sacks, now positioned crossways to the machine axle, are then subjected to the remaining stages of the process: optional corner sealing for sacks with an internal plastic lining, carried out with ultrasound due to the high production speed, the edge-trimming of the sack opening and the welding of the longitudinal seam of the base of the sack using pressure and heat, before this is folded. The last stage in particular requires time; the solution was a drum which receives and bonds 12 tubes at a time. So, each individual sack, up to a maximum of 250 sacks per minute, can be welded in 3.6 seconds. After another alignment, the sack base is glued and laid. Poorly constructed sacks are removed after a quality check, which compiles and counts sacks into stacks at the continuous feed and counting station.

Cooperation which really pays off

The system was equipped solely with automation components from Siemens’ Totally Integrated Automation concept. This means that all components are optimally suited to each other and interface problems do not occur at all. Profibus DP connects the Simatic OP27 operating unit, the Simatic S7-400 controller, all the sensors/actuator signals, Micromaster frequency converters and Simovert Masterdrives MC servo converters. A modem connection facilitates remote diagnosis and service.

The 19 Masterdrives MC devices for the servo drive technology in the folding system are synchronized via a fast fiber-optic cable connection. They do not just have functions typical to servo drives such as power, speed and position control, but also positioning functionality, electronic cam discs, electronic coupling and electronic cam control.
The combination of progressive mechanical engineering and expert solutions from the Siemens Packaging Department has certainly paid off for Korsnäs. Both production capacity and quality have been considerably improved.

Drive, Switch & Control 3 / 2001 (More featured topics from Siemens website...>>)


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