IBT Builds Robotic Palletizer System for Dairy Products
Working in a cool (35° F/2° C) environment, stacking dairy products on pallets is a job, to be sure, but not necessarily a fun one. When a large dairy products company wanted to improve productivity and reduce the discomfort of its staff, it turned to IBT Engineering Services. They, in turn, looked to robotics and created a high-output system.
Their solution uses an ABB FlexPalletizerTM system, featuring an ABB robot and S4C System controller.
Recently installed, the new system shows signs of exceeding customer expectations, meeting aggressive targets for output, increasing plant packaging flexibility and – ultimately – paying for itself in cost savings and revenue increases.
The FlexPalletizer robotic system is able to handle product at rates from 16 up to 25 products per minute. It is configured to palletize using four different pallet types and 21 different load patterns. Palletizing patterns are varied, depending on the product, container size and type and other factors, such as cooling efficiency. One challenging aspect of the project was the need to palletize the various different product container types, including dairy cases, plastic pails, corrugated boxes and shrink-wrapped products.
An operator, through an easy-to-use interface panel, controls the system. Products and palletizing patterns are preprogrammed offline and then loaded into the system. The system may use alternating layout patterns to load pallets securely.
At the start of a product run, an operator selects the appropriate palletizing pattern which includes a specific pallet and product. The system is now ready for the pattern to be followed and will handle the material accordingly. Product selection can be done for each separate run before starting the system.
Prior to starting the system, a fork truck operator moves a stack of pallets into place, using the, floor mounted pallet locator brackets. These brackets assure that the pallets are placed correctly: square and properly oriented. The fork lift will then periodically reload pallets as needed.
Moving robotic elements can be potentially hazardous. Therefore, IBT included a safety system, which provides security for the work cell and works to prevent accidents involving the robotic system and any live workers. This is primarily accomplished using a gate that controls access to the robotic work area. Whenever the access gate to the Robotic Work Cell is opened, the robot stops and remains stopped until the gate is closed – and the robotic palletizing cell is restarted by the operator.
Products to be palletized are fed from upstream conveyors onto the infeed conveyor. The infeed conveyor is made by Hytrol. Product comes in lengthwise and is positioned when necessary by a bump turn, so that it presents itself with correct orientation to the robot. When product does not need to be turned, a diverter causes the bump turn to be bypassed. This allows for higher throughput rates.
When the sequence starts, the robot picks up an empty pallet from the pallet stack and places it into position on the outfeed conveyor, also made by Hytrol.
Product flows to the robot’s pick table, where the machine – using “forks” and a “bar” to hold product in place while moving, will place it. The sensors on the infeed conveyor communicate with the robot, so the robot has the right quantity to be picked up. As the material accumulates, the robot picks it from the conveyor and places it on the pallet, building a product pattern that will be transported easily and securely.
In the case of plastic dairy cases, the engineering team faced an unexpected wrinkle. Unlike most of the product the system handled, there were some package size variances. Dairy cases were from different vendors and came in slightly different heights, lengths and widths. The wear on some of them further increased the potential variability.
In order to make sure that they stacked securely, the engineers had to rely on a “trick,” When the robot places its row of dairy cases on the pallet, it give the goods a slight “shake.” This allows the cases to nest and the stacks to be strong and secure. When you watch the video of the robot in action, you’ll see how this little “trick” works to solve the potential problem.
When a pallet is completely loaded, the pallet is moved out of the Palletizing Cell to the stretch wrapper. If the stretch wrapper is unavailable, the system has the capacity to store two loaded pallets. These are sent on to the stretch wrapper when it is available.
Then, another empty pallet is picked from the empty pallet stack and positioned on the conveyor. The process then starts anew.
For this application, IBT chose the ABB FlexPalletizer with ABB’s IRB-640M2000A 2. 9/160 robot and S4C System controller. The robot is mounted on a base, fitted with an EOAT (end of arm tooling) that was custom designed by IBT Engineering. Infeed and outfeed conveyors are provided, as is the safety fence that guards the robotic cell.
The system operates using 4kVA 480VAC 3 phase power and also requires 2cfm compressed air at 90 psi (estimated).
The FlexPalletizer can manage more than 1200 cycles per hour and is the quickest robotic device in its class. It has a lifting capacity of 160 kg (352 lb.). The unique, self-optimizing dynamic model control ensures that at least one robot axis is always running at maximum torque, resulting in the fastest cycle times in the industry.
The FlexPalletizer is optimized for fast point-to-point movement. It features 4 axes, a 2.9 m long arm (9.5 feet) for greater reach, and shorter cycle times to boost performance. The robot works along accurate paths, regardless of speed.
The robot has an end of arm tool that works as a mechanical gripper. The gripper consists of a fork that goes underneath the product and a pressure plate on top to securely hold the load in place. The gripper also has pallet gripping fingers and a pallet stack height sensor. This enables it to pick and place pallets.
The S4C controller with touch screen panel PC provides all control functions for the robot. The PC panel guides the operator through all standard procedures, system configurations and error events. The intuitive interface is very easy to operate. The built-in soft PLC provides the communications with all components and the user interface. It takes care of the administration of peripherals. It also includes special concern for customer obstructions and excellent error handling in the event of non-picked boxes, pallet transfer and handling problems, and process control.
PalletWizard is a PC based software package that defines the products, patterns, and loaded pallets and then automatically generates robot programs. The acceleration and speed of robot movements when handling a certain product can also be individually set. PalletWizard can be used off line and can be used while the FlexPalletizer is running.
The FlexPalletizer utilizes ABB’s PalletWare software. PalletWare executes modules generated by PalletWizard, to which it is directly linked. The sophisticated PalletWare software compensates for variations in box sizes with on-line tuning and can handle multiple placing. PalletWare supports a large number of pallet stacking patterns and different patterns can be used for different layers. Ready-made functions ensure that the robot can handle changes of pallets, slip sheets, tier sheets and top covers.
PalletWare allows the user to handle single or multiple products simultaneously. Several products can be taken from an infeed conveyor at the same time and then placed on the pallet one by one or several at a time.
For more information about robotic applications for palletizing – or any of a full range of other material handling applications – you are invited to contact IBT Engineering Services.