Fehlt Lohr, 2010-02-11

Rexroth Focus Shrink packer Smiflexi SK 600T: Simple architecture for fast format changeover


More flexible, faster, easier: In the packaging industry more and more machine builders use SERCOS III to reach a higher overall productivity with innovative machine concepts. For example Smigroup, a worldwide leading manufacturer of packaging machines: In its newest generation of shrink packers, the SK series of the Smiflexi division, the Italian Company uses SERCOS III as universal bus for the complete automation and combines short format changeover times with a high throughput.

At Drinktec 2009 show Smigroup presented the newly developed Shrinkpacker SK 600T. It can pack a wide range of containers, like bottles, cans, jars into film, in film only, cardboard pad plus film, tray only, or cardboard tray plus film: “The batch sizes in mineral water, soft drinks and lemonades are decreasing because of the high competition and our customers take care about short format changeover times”, says Pietro Volpi from SMI. The electrical cam shaft of the machine with 16 compact Rexroth IndraDrive Cs servo drives reduces the change over almost completely to software commands.

Italy-based company SMI is the largest manufacturer of hi-tech secondary packaging machines, and one of the leading manufacturers of rotary stretch-blow moulding machines. Smiflexi division markets about 300 shrinkwrappers and wrap-around casepackers every year, capable of output rates from 20 to 360 packs/minute. Smiform division produces approximately 50 stretch-blow moulders per year for the making of PET and PP containers.

The North Italian engineers decided for the use of the real time communication SERCOS III for all servo drives and I/Os in the new machine. “This simplifies the architecture and gives us the choice of components from different suppliers”, states Pietro Volti from SMI. The control MARTS 3000 developed by SMI communicates over Ethernet with all actors and fieldbus devices. SERCOS III reaches 40 participants with a cycle time of 1ms. The simple integration of products of different suppliers with Ethernet interface reduced the engineering time by almost one third, SMI is already using SERCOS interface in various machine concepts. SERCOS III has implemented real time mechanisms, profiles, datagram structure and synchronization from its predecessor. "Additionally, SMI has already integrated innovative SERCOS III functions such as redundance into its new architcture", points Luca Stanzani, Industrial Sector Food and Packaging of Bosch Rexroth in Italy.

Because of the hard synchronization of SERCOS III and the highly dynamic servo drives, the SK 600T packs up to 60 packs per minute in single lane operation. All machine types of the SK series are already prepared by SMI for multiple lane use with electric grouping of products. SERCOS III technology of real time direct cross communication between controls enables machine-builders and end users to synchronize different machines and modules easily. “With this technology all customers can configure their complete packaging lines for highly flexible Inline processes.” underlines Pietro Volpi.

In addition, various innovative solutions are reducing the time of format change over: The self-adjusting product infeed guiding rails, adapts automatically to the different pack sizes with nearly no manual adjustment of the operator. All movements starting from the grouping of products, unwinding of foils to the automatic alignment of printed foil are controlled with the servo drive IndraDrive Cs, which has a performance range from 0.05 to 3.5kW. The highly compact multi-ethernet drive IndraDrive Cs are the standard configuration with multi-encoder interface the most used encoder types. This simplifies the logistics for SMI and the end user, because one hardware covers all options within the machines.

The new SK 600T reaches a high efficiency also due to reduced energy use: “Users can produce the heat for the shrinking tunnel with electric or methane” explains Pietro Volpi – the automation components of both versions communicate via SERCOS III with the controller.

Bosch Rexroth AG is one of the world’s leading specialists in the field of drive and control technologies. Under the brand name of Rexroth the company supplies more than 500,000 customers with tailored solutions for driving, controlling and moving machinery used in industrial and factory automation as well as in mobile applications. Bosch Rexroth is a partner for industrial applications and factory automation, mobile applications and using renewable energies. As The Drive & Control Company, Bosch Rexroth develops, produces and sells components and systems in more than 80 countries. In 2008 Bosch Rexroth AG, part of the Bosch Group, achieved sales of around 5.9 billion Euro with 35,300 employees.

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