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Article | August 11, 2014
Lightweight robot arms case-pack eggs at 15,000/hr
Italian egg suppler installs four robot arms to case-pack different size cases that accommodate volumes from 96 eggs to 1,400 eggs, eliminating labor-related issues and improving its operational efficiency.
A fourth-generation, family-owned company, Cascina Italia SpA is one of the leading Italian suppliers of eggs and egg products. Located in Spirano, Italy, the company’s egg production facility processes up to 2.5 million fresh eggs per day. To survive and thrive in this highly competitive market, Cascina is committed to creating high-quality processes—from the production of feed for its hens to the packaging of its products.
Says Ruggero Moretti, Facility Manager of Cascina Italia, “Our company joined the egg sector 15 years ago to complete the agricultural chain managed by our group, which has been working in the milling and feed industry since the 1920s and has stood out ever since thanks to the high-quality products it produces. We have applied the same philosophy to the egg sector. Our strategic objective is to focus on quality and innovation through technology as the way to obtain that quality. This is a complex challenge in a market that often suffers from low profit margins because of the variations in cost of raw materials…and the cyclical impact that different regulations have on the egg production chain. For these reasons, operational efficiency for us is not a luxury, but fundamental to guarantee the survival and growth of our company.”
At its egg processing facility, Cascina packages up to 1.5 million whole, fresh eggs per day, operating 24 packaging line output stations; another production line handles egg products destined for the food and confectionery industry. On its whole egg packaging lines, automatic packaging equipment fills plastic cartons with eggs that are then packed into cases of various sizes, depending on customer requirements.
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Until recently, cases were packed manually—a highly repetitive, non-ergonomic, and time-consuming task. To eliminate these labor-related issues and improve upon its operational efficiency, Cascina installed four UR5 six-axis robot arms from Universal Robots, supplied by Italian distributor Alumotion, on four of its packaging lines handling products for large-scale distribution. While three of the lines are flexible—handling 96-, 144-, or 192-egg case sizes—the fourth is a dedicated line that packs cases with 1,400 cartoned eggs.
Among the features that attracted Moretti to the UR5 robot arm were its light weight (18 kg), its compact design, and its ability to operate without safety guarding. “It was important for us to be able to install the robot in areas with limited space to retain the full flexibility we need to be able to react to the demands of the market,” he says. “This allows us to produce more than 220 commercial options in different formats, depending on the type of packaging required. Being able to install one or more robots on our production line, without having to sacrifice the other stations because of a robot’s size, was a basic requirement for us, and Alumotion’s expertise enabled us to achieve this tough objective. The fact that the robots from Universal Robots are also able to work alongside our human operators without us having to install specific protective barriers—a unique feature of these robots—turned out to be the key for us.”
During operation, a case-erecting machine integrated with the UR5 erects the box, and the robot picks cartons filled with 10 eggs from a conveyor leading from the carton packer and places them into the open case at 15,000 eggs/hr. Programming for each case-packing station is customized to meet the specific needs and level of automation required. Each robot waits for a signal that indicates that a filled carton is in place, with signals double-checked and filtered to avoid false positives. Once the case-packing process begins, the robot places the cartons into the boxes in layers, from the bottom up. A force control feature on the robot ensures that the eggs will not be broken if something goes wrong during the process.
Explains Fabio Facchinetti, Alumotion Head of Technology, “In this specific application, we made the most of the abilities of the UR5 robot in terms of its extension so that it could reach the entire work area and carry out its movements quickly, but at the same time delicately—absolutely necessary for packaging eggs. With little space available to install the robot on the existing production line, we optimized every route based on the robot’s position to ensure that there was no interference with the operators, enabling them to work on the output station next to the one where the robot is working at the same time.
“We also designed and built the pneumatically controlled gripper for handling the egg cartons in a way that will ensure safety, without having to install protective barriers in line with regulations.”
Confirms Moretti, “Safety is of course essential, and with the innovative technological solution adopted in the robots that enables them to stop on their own at the slightest touch, combined with the adoption of a gripper that has no dangerous elements, we have been able to install a robot into our facility in compliance with all necessary safety standards.”
Ease of programming is also a benefit for Cascina. The UR5 robot is programmed on-site via the Universal Robots user interface—the Polyscope GUI—available on the touchscreen panel; no offline activity is required. The system’s teaching mode allows the user to move the robot arm by hand to program complicated movements on the fly. “This makes it very easy to design and apply the special filling trajectories that let the robot put the eggs into the boxes with a high speed and very low clearance,” say Universal Robots. “For example, the program that fills the box with 1,400 eggs into nine layers (six placing positions per each layer) required the creation of 54 special trajectories, and we were able to do this in just one day.”
To coordinate functions with other machines on the packaging line, the UR5 communicates by way of Ethernet and Modbus/TCP. All stations are monitored by the production manager, who can change the size of the eggs, the package label, and the quantity of eggs per each carton according customers’ needs.
Once the cases are full, the robot signals for the case to be conveyed away from the station, and a new, empty box takes its place. Because all four filling stations release their filled cases onto the same downstream conveying line, it is necessary to synchronize the stations in order to avoid collisions. The logistics that handle the release priorities are implemented in each robot into a parallel thread. While the main program takes care of moving the eggs, this thread checks that no upcoming cases are approaching and counts the boxes that are entering a critical portion of the downstream line close to the point where the case-packing station is placed. When the thread decides that a box can be released, it informs the main program, and the releasing process begins.
With the installation of its first four robots, Cascina is sold on automated case packing with the UR5. Says Moretti, “We are convinced that the collaborative robot solution is extremely useful for facilities like ours that have constraints on flexibility, available space, and budgets for investment, which make traditional robotic solutions difficult to implement. The results obtained so far are excellent—so much so that we expect a return on our initial investment in less than a year, with the additional advantage of having further refined and improved the quality of our packaging processes.”
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