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Single Robot Packs and Palletizes
One-Stop Operation Saves Floor Space and Cost
By Design News Staff -- Design News, April 10, 2005
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| Several pieces come together in the combination packer and palletizer (CP-P) system and take less floor space than the two separate systems. |
When a customer with floor space constraints required packing and palletizing, Schneider Packaging found a solution by combining the two activities. Typically, one machine does the case packing and another does the palletizing and each one has a robot. Since a single robot could handle the production rates, integrating functions proved to be the right solution.
Schneider engineers designed the Robotic Case Packer-Palletizer (CP-P) to provide as much functionality as possible with a single robot. The CP-P loads, labels, scans and palletizes cases in about two thirds of the floor space. In addition to the reduced the footprint and system cost, the unit provides flexibility for future product changes since the robot can be reprogrammed for different products and different cases sizes. Key components of the system include:
1- Case erector
2- 5-axis robot
3- Case Sealer
4- Touch screen operator interface
To start the process, an attendant manually loads blanks in the case erector magazine and places an empty pallet inside the robot cell. Product transfers onto the Schneider infeed conveyor in single file for collating into the proper pack pattern. The robot positions the accumulated product in front of the load station for case loading.
The case erector automatically selects a case from the magazine and erects it for case loading. The robot then picks cartons from the infeed conveyor and loads them into the erected case. After loading, the case proceeds through the flap folding and sealing stations for sealing with a pressure sensitive tape applied to the top and bottom. The finished case is then discharged.
The robot swings back into action and picks up the sealed case to check for open flaps using a photoelectric detector. If the flaps are open, the robot stops and alerts the operator. If the flaps are closed, the robot takes the case to the labeler/scanner station. This station labels the case and then scans it. If the labeling is correct, the robot takes the case and passes it in front of an ink jet printer, and then places the case onto the pallet in the appropriate pallet pattern. If the scanner could not read the label, the case is presented to the operator behind the fence for operator inspection, while the robot waits for the operator to inspect the case.
When a unit load is completed, a flashing beacon signals the operator. The system pauses so that the forklift operator can safely enter the cell, remove the full unit load, and install another empty pallet for the next cycle. An Allen-Bradley Logix controller co-ordinates the operation of the robot with the case erector in the cell and the taping machine as well as the bar code reader. A PanelView 1000 provides the touch screen operator interface and simplifies changeovers. While it sounds rather straightforward, there are two process elements that provide the core technology: the robot (see sidebar) and sophisticated tooling to enable the robot to pick up a variety of products.
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| Between the incoming product and the completed pallet, the packer and palletizer process has six key steps. Quality control in the process includes scanning the labels and photoelectric detector inspection of sealed flaps. |
Custom Tooling
The end of arm tooling (EOAT) for the robot required a custom solution. A single robot had to pick up smaller products, put them into a case without incurring interference, and at the same time, handle the entire case. If the packaging assembly was going to provide two functions in one continuous operation, the EOAT had to be able to handle both small product and the large case without changing the tooling.
By evaluating the products, the number of units to be picked, and how they would be packed, Schneider engineers designed a tool that implemented both mechanical positioning and vacuum suction. Eight suctions cups on the EOAT provide the pick and place capability for products. The custom designed EOAT is flexible enough to pick up and pack various size objects, including boxes, bags, bundles, bales, cans, bottles, and jars. Mechanical fingers keep the objects inline and handle the larger cases.
Increasing Throughput
The machine handles pallet sizes of up to 48-inch x 48-inch and unit loads up to 72 inches high. Production rates for the CP-P depend on several factors, including the product itself, the number of products per case, and pallet patterns. However, the CP-P unit can handle single or multiple conveyors. Schneider engineers designed the system for future expansion by analyzing the rates and reach of the robot. Adding a second line to the cell is well within a single robot’s ability to handle the process.
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| The custom end of arm tooling (EOAT) consists of a combination of eight vacuum pickups and mechanical fingers to maintain position of the stack during placement in the carton. The robot arm can pickup a payload up to 80-kg (176.4-lb.). |
ARMED AND READY
The key to movement within the system is a 5-axis, high-speed robot, Motoman SP80X, designed specifically for palletizing applications. One of the required features was a programmable robot that could run multiple programs. The XRC 2001 robot controller has this programmability as well as standard network options for connection to the programmable logic controller.
In the CP-P, the robot first performs the case packing program and then it executes the palletizing program when the cases come out of the sealer. The robot handles an 80-kg (176.4-lb.) payload capacity, with a maximum horizontal reach of 2,046 mm (80.6 inches) and a maximum vertical reach of 3,194 mm (125.8 inches). The unit’s 360-degree work envelope can service multiple infeed conveyors and a single pallet loading station.
