Multi-pack’s multi benefits

Smith’s Space Efficient Multi-Pack is a project that achieves the goals of the marketing, engineering and manufacturing departments, while managing to deliver a host of supply chain benefits at the same time.

The multi-pack concept has become a strong family favourite in Australia over the past decade, with a wide variety of snackfoods, such as chips, cookies and crackers, now available in multi-packs.

However, the large volume of multi-packs makes them expensive to handle and transport with a lot of air being handled and shipped through the supply chain. The bulky nature of the multi-packs means they also take up a lot of precious shelf space in retail outlets.

To create clear product differentiation in an increasingly crowded market segment and reduce manufacturing and supply chain costs, Smith’s developed the Space Efficient Multi-Pack (SEMP).

The multi-million dollar project involved the design and installation of a world-class robotic packaging system and associated materials handling systems at Smith’s Tingalpa Production Plant in Brisbane. The SEMP Project team included Smith’s engineering consultant Shandon Projects and technology partners International Packaging Systems (robotic packaging line), Cermex (case packers) and Dematic, which supplied the conveyor system that interlinks various parts of the operation.

The goal of the SEMP project was to help reinvigorate sales in the highly competitive multi-pack arena, with the new SEMP cartons providing a clear point of differentiation for Smith’s on crowded supermarket shelves. The retailer is also able to fit more products in the same area as before, and the new shipper pack, which contains six SEMP cartons, is shelf-ready for those retailers who wish to use that format.

Smart packaging system

The main feature of the upgrade, the robotic packaging system, was installed in a 13 x 50 metre extension at the eastern end of the packing plant.

The SEMP robotic packing line comprises ten robotic packing stations, each with two robot arms fitted with gentle vacuum gripping attachments that enable them to precisely place packs into cartons in a pre-determined location. As empty cartons pass through the robotic packing line, the first inners are placed by the first robotic station, then the next ones by the second station and so on until the carton is full. The accuracy with which the packs are placed means volume in the carton is used effectively.

Supporting the new robotic packaging line is a smart Dematic conveyor system that interlinks various processes and fulfils the role of removing empty Work-in-Progress (WIP) boxes containing bulk quantities of inners from the packaging line and returns them to the packing plant’s interface with upstream production.

A key challenge in designing the new conveyor system was to proof-test the design by computer simulation to prove the conveyor could remove and return the empty WIP boxes for reuse at the required throughput rates.

Dematic’s simulation identified that transporting the WIP boxes individually would create congestion on the conveyor system and reduce the throughput of the system to an unacceptable level.

By investigating various options such as conveyor speeds and routing etc, Dematic identified that the best way to ensure a sufficient quantity of cartons could be transported within a given timeframe was to utilise slug transport of the WIP boxes. That means, slugs of up to 18 WIP boxes would be formed on accumulation conveyors, and would then be transported as a slug. Transporting a slug of cartons is much more efficient than transporting cartons individually as the gaps between the cartons are removed, enabling a greater total number of cartons to be circulating on the conveyor system at any one time.

The simulation also identified that the return of empty WIP cartons from the robotic filling and packing station would ‘overload’ the conveyor system within 10 minutes if the WIP boxes were not being reused by the production lines or removed from the conveyor. This issue was overcome by the addition of an extra conveyor loop from which empty WIP cartons could be easily removed from the conveyor and palletised until needed at a later stage.

The simulation also identified how long it would take for a problem at any point on the conveyor system to impact upstream or downstream.

This was particularly important in determining how long it would take for any local issue on the conveyor system to impact the upstream manufacturing process. The simulation also determined the time required for the system to be fully restored after any such incident.

“Dematic’s simulation gave us a lot of confidence in their design options,” said Smith’s national project engineering manager, Steve Reilly.

“The fact that we could see in real-time how the whole system would operate was very reassuring for the project team.”

A challenge for Dematic was installing the WIP conveyor system within the sensitive packing environment without the need for any ‘hot work’ such as welding and grinding, with every connection in the system that would normally have been welded, being converted during the design phase into a bolted connection.

The SEMP project also has excellent green credentials, removing up to 350 tonne per annum of non-recyclable plastic wrap from landfill. The cardboard used to manufacture the SEMP cartons has a high recycled content and the carton itself is also likely to be recycled.

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