Extreme Machine: Compact Precision Robotics
Not just a cartoner or a case packer, this complete end-of-the-line packaging system sits within 300 sq ft.
Steve Scheiber for Control Engineering -- Control Engineering, 4/1/2007
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What's extreme? According to Control Engineering subscribers, a robotic packaging machine that's small, nimble, and easy to use and adapt, while ensuring safety. When Rockwell Automation wanted to highlight the creativity of its machine-building customers, it asked Control Engineering, Control Engineering Europe, and Design News readers to select the ultimate “extreme machines.” Eight contestants (four from North America, and four from Europe) appeared in October 2006 issues of all three publications, and readers were asked vote. The North American winner is Schneider Packaging of Brewerton, NY.
What makes an ultimate “extreme machine?” In evaluating the candidates for this year's competition, readers were asked to look for a combination of utility, precision, and practicality. In the case of Schneider Packaging's entry, they also apparently appreciated a machine that occupies a limited amount of factory floor real estate.
Automated control requires sophisticated mechanical apparatus that can provide precise movements to accomplish the designated task. Greater capability, however, often means big machines that take up lots of room. In addition, many robot manufacturers expect operators to interact with their robots through the conventional teach pendant and to enter the safety enclosure for routine tasks, such as supplying a labeler with rolls of labels.
Break the mold
Schneider Packaging Equipment takes a different approach. It provides machine configurations that improve productivity while simplifying the process. For this application, the company created an end-of-line robotic handling system for “K-cups” from a premium coffee roaster that occupies a miserly 300 sq ft. The sealed plastic cups of ready-to-brew coffee go in one end, and a pallet of labeled cases comes out the other. Aside from replenishing packaging supplies, humans enter the safety enclosure only to remove the completed pallets. Even that limited level of intervention could have been avoided by carrying the pallets out on a conveyor, but in this case the customer preferred the manual approach.
Operators stack carton and case blanks and supply the labeler from outside the enclosure because stopping the line to enter the enclosure is time-consuming and expensive. K-cups come in on a conveyor at 280 cups per minute. Two side-by-side timing screws count the appropriate number for a carton and feed them into a hopper. A Rockwell Automation Ultra-3000 servo with MPL motors operates the timing screws. The machine opens a carton and, when the hopper is full, dumps the cups into the carton. To save space, Schneider developed a rotary cartoner, operated by another Ultra-3000.
A series of air cylinders controlled by a Rockwell Automation ControLogix processor then pushes on the carton sides and bottoms to settle the K-cups so the correct number will fit. This complex “settling” step must account for the cups' harmonic responses to avoid throwing them from the carton.
The machine applies hot-melt glue to seal the carton and presents it to a laser date coder and a label applicator. The carton then travels down a very short conveyor to the combination robotic case packer and palletizer.
Cartons accumulate in the proper pattern for a case. The machine opens a case blank so that a Fanuc R2000 robot can lift a layer of cartons and place it into the case, repeating the step if the instructions call for more than one layer. Another hot-glue application allows sealing the case, after which the machine spits it out.
The same robot then picks the case up and presents it to the labeler. The entire labeling assembly resides outside the safety enclosure, permitting operators to service and supply it without shutting down the line. It performs its task through a small cutout in the guarding fence. Many automated processes of this type require a separate labeler if the customer wants to label more than one side of the case. In this situation, however, the robot presents a side for labeling, then. if another label is needed, turns the case and presents it again before placing it in the correct location on the pallet.
Simple operation
According to Pete Squires, vice president of Schneider Packaging Equipment, “One of this system's biggest attractions is its simplicity. All 'canned' robots come with a teach pendant, the interface through which it gets programmed. With most robotic integrators, operators [also] interact with the robots through the pendant. Since most companies don't want their operators to double as robot programmers, we lock the pendant away. The operator interacts with the robot using a touchscreen interface on the machine. Everything is integrated with the ControLogix controller, which runs the show.”
Squires admits that providing so much functionality in a robotic system and cramming it into such a small space presented a considerable challenge. It wasn't only a cartoner or a case packer, but an end-of-the-line packaging system. Also, the company never had constructed a rotary cartoner before. It met the challenges by inventing new functions when necessary and re-configuring proven functions into a modular design—and delivered it all in less than 5 months.
“It's a very complex machine,” says Squires. “But that's par for the course for us. When a customer asks us 'How many of these units do you have in the field?' our answer is often, 'This is the first one.'”
Steve Scheiber is a contributing editor at Control Engineering, sscheiber@aol.com.
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