A WORLD-CLASS Australian manufacturer with a string of leading brands behind it was clear on three points when it came to the automation of its new production line at its manufacturing facility in Sydney: eliminate occupational health and safety issues; reduce labour costs; and increase production capacity.
Integral to the automation of the production line and its three new packing machines would be the installation of a palletising system that could deliver on those three key points.
A challenge in any industry involving palletising, where manual systems are notoriously labour intensive, time consuming and plagued with the occupational health and safety issues associated with heavy lifting.
Robotic palletising at work
The system principle delivered by Machinery Automation & Robotics (MAR) was simple: automate carton handling; automate pallet handling; automate stretch wrapping; install a single robot system to perform the process; design a user-friendly touch screen; and the entire palletising system to be controlled by a single operator.
At system start up, the operator loadsa stack of up to ten empty pallets into each of the Chep and Export pallet stack frames. These pallets — of which 20 can be accommodated at any one time — are then automatically conveyed to the pallet pick-up position. Using the PanelView touch screen the operator determines the criteria by which the system will function.
After ensuring that no personnel are within the cell the operator closes the switch-protected safety gate and uses the touch screen to start the robot system.
The robot system, which provides continuous operation during the palletising process, comprises of a robot which distributes the empty pallet stacks to the loading stations. If required at this stage, the robot picks and places a pallet layer sheet onto the appropriate empty pallet.
As cartons are received at the in-feed conveyor sensors count the required quantity to commence pallet layering. When the correct number of cartons is reached, a stop plate prevents additional cartons from entering the final pick-off point.
Moving to the carton in-feed conveyor the robot grips the set of cartons and raises them from the conveyor. Following system confirmation that the cartons are securely gripped the robot transfers the cartons to the loading station and continues the palletising process until a pallet load is complete.
Each fully loaded pallet is removed from the loading station to the 90-degree conveyor transfer, from where it travels along the main trunk line before exiting the cell through the muted safety light curtain. The pallet then enters the stretch-wrapper where, if preselected by the operator at the PanelView touch screen,it is wrapped prior to exiting the system for the pallet pick-off point.
Design of the robot palletising system
provides the flexibility of manual stretch-wrapper in-feed in addition to the fully automated process.
The pallet conveyor section between the robot cell exit and the stretch-wrapper entry points allows pallet placement by a forklift operator for automatic stretch-wrapping.
The break in the light curtain, created by the forklift operator entering the area, powers down the section enabling the pallet to be placed on the conveyor. The driver simply presses the reset button as he clears the light curtain to activate the conveyor section.
All completed pallets exit the stretch-wrapper, whether preselected for wrapping or not, and are ready for removal by the forklift operator.
In a similar process to the manual stretch-wrapper in-feed system the conveyor is powered down by a break in the light curtain, the pallet is loaded and the forklift driver exits the area and reactivates the conveyor section.
Control at your fingertips
Operation of the entire robotic palletising system and conveyors is controlled from the colour PanelView 700 Human Machine Interface (HMI) touch screen located inside the robot enclosure.
The ten-page program includes primary control for system start/stop function and a graphical display to assist the operator.
In addition the program provides a dedicated page for each of the following: manual control of conveyors; manual control of the gripper; shift production data; error reporting; robot control in service position; and robot control in the elevated home position, maximising access around the cell during maintenance and cleaning operations.
The touch screen program also incorporates a number of selection options enabling the operator to determine: carton tuning to allow for changes in card production and case packing tolerances; the products to be palletised; the number of carton layersper pallet; the pallet station to which the product is to be transferred; the type of pallet — Chep or Export — to be used at each station; whether a pallet sheet isto be used at each station; and finally, whether a completed pallet is to be stretch-wrapped.
The automated system upgrade also enabled two specific features to be incorporated into the design of the system cell: firstly, that no part of the robot or gripper make contact with the perimeter fence or the four surrounding walls; and secondly that the area within the cell be maximised to ensure free access around the robot and conveyors for cleaning, maintenance and general operation.
Technology at work
Automation delivered a range of benefits including the manufacture, supply, installation and commissioning of a complete robotic palletising system, and the elimination of all manual handling during palletising operations, resultingin significant labour-cost savings and adherence to occupational health and safety standards
The high-speed palletising system can process up to three cartons per cycle and complete a minimum of eight cycles per minute
Incorporating four separate carton in-feed conveyors and four pallet-loading stations within a single cell, the system is flexible allowing both Chep and Export pallets to be processed simultaneously within the cell.
The control system features an Allen Bradley MicroLogix PLC mounted within the robot enclosure, while the operator workstation features a cabinet-mounted Allen Bradley colour PanelView 700 HMI touch screen located within the enclosure
The four-axis industrial robot system comprises a KUKA KR180PA featuringa 180kg payload capacity and 3200mm reach, while the robotic gripper systemis fully customised anc accommodates varying empty pallet dimensions of 1165x1165x145mm (Chep) and 1100x1100x130mm (Export).
The system has the capacity to simultaneously transfer three 16kg cartons and up to 50kg mass in empty Chep or Export pallets, with an automatic stretch-wrapper located at the pallet conveyor out-feed.
A total of four 2500mm carton in-feed conveyors supply cartons to the four pallet-loading stations.
Machinery Automation & Robotics 02 9748 7001.