Author: Gary Sweeney, managing director of conveying and materials handling specialist Exmac Automation.
A recently completed upgrade of a palletising system for a major logistics company has significantly improved flexibility at its multiple packaging facility in Cambridgeshire. Automating packaging processes that had been previously handled manually have created significant improvements in flowline efficiency while also reducing pack damage caused by manual handling.
The customer’s site receives cans and pouches of cat and dog food from a nearby processing plant, removes them from trays and, using a combination of manual and semi-automated systems, places them into packaging machines before they are shrink wrapped – typically into cases of four boxes. From this stage, three quarters of production had previously been manually palletised and the balance palletised using an existing robot. To aid rigidity when stacking, most pallets would then be fitted with cardboard corner boards held in place with masking tape applied by hand. Pallets were then transferred onto an automatic stretch wrapper by forklift truck and transported to the dispatch yard. An additional robot and a conveying line was also introduced, which reduced costs and avoided major staff re-training.
Exmac was one of the specialist companies invited to improve the efficiency of both the palletising and delivery-to-dispatch systems, by automating the existing process. The contract was awarded on a combination of cost, the fact that Exmac was UK-based, and our logistics design team understood the company’s objectives and introduced ideas that they hadn’t thought of!
Our in-house control team, created complex software to integrate existing and new equipment, and developed universal software to manage the system’s diverse functions.
Product is now delivered in cartons where three lines feed into a new Exmac-designed and installed palletisation area comprising two robots (one existing, one new), conveyor systems – one we supplied plus one FOC from another customer site – the corner board machine and a shrink wrapping machine.
The Exmac materials handling solution featured one of our clutched UB500 case conveyor systems to collect product from the packing lines, and deliver it on three Exmac conveyor systems into a twin-robot cell specifically designed to enable two the robots to palletise the throughput from all three lines.
To insert pallets, two separate pallet destackers are installed, one for Chep pallets and one for Euro pallets. The destackers automatically deliver pallets into each zone of the new robot cell, and into the existing robot cell.
The robots use unique vacuum grippers able to handle cases in various arrangements to suit eight different layer patterns for both pallet types. This enables the customer to respond quickly to demands for any product. The gripper is also designed to collect loose trays, which are fitted to certain products to prevent them slipping from the case assembly.
In addition, one customer requested that, after pouches are put into cartons and sealed, batches of eight cartons be loaded onto its own purpose-designed trays. To accommodate this special requirement we sourced a new robot gripper design and re-programmed the software to introduce the special trays. Fortunately, using our in-house control team, we were able to deal with the changes efficiently, and the system was fully integrated within the operation.
At the final palletising stage a cardboard pad has to be fitted between certain layers on each pallet. The layer pads are delivered into the robot cell on a trolley system, where outboard suction cups on the robots’ gripper pick a single pad and position it accurately onto the pallet stack.Full pallets leave the robot cells on a series of Exmac chain and roller conveyors and are fed onto the main outfeed line where pallets are checked to confirm they are fully loaded and any ‘short’ pallets are automatically diverted to a secondary outfeed lane.
Next, we introduced a barcode reader to identify each pallet’s product type before transferring it by conveyor to a corner-board fit machine. This receives information from the barcode reader, first to confirm whether or not the pallet requires corners and then to identify the size of pallet and type of corners required. If corners are to be fitted the pallet moves into the corner-board machine and stops in its pre-determined position, where a banding tape is fitted to secure them.
Pallets then leave the machine to await a routing decision on a turntable that will either deliver them into the existing stretch-wrapper or re-route them onto a conveyor for delivery to a new stretch-wrapper. As pallets leave the wrapper they are again identified by the barcode reader, this time to download data for a three-face label applicator, which prints and applies a unique label to three sides of each pallet, enabling retailers to identify the content. Pallets are then dispatched to an unload station.
The key to the success of the new palletisation area was identifying a significant problem with the previous layout during our project review. While the existing system automated the pouch lines it prevented the canned product line delivering pallets to the wrapper. We resolved this problem at the layout planning stage by developing an extension of the canned product conveyor line to merge with the pouch product conveyors before they reached the wrapping machines, enabling canned produce to also be automatically wrapped and labelled.
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