Extreme Machine: Compact Precision Robotics
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.
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.
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, firstname.lastname@example.org .
Extreme sausage making also garners a prize
The European winner of the “Extreme Machine” contest was food machine manufacturer Stork Townsend B.V. located in Oss, The Netherlands. Its QX family of co-extrusion sausage makers takes raw meat as feedstock and produces finished smoked sausages ready for shipping in a continuous operation with 80% labor savings.
So, what is so “extreme” about a sausage maker? For one thing, its size is massive: 10 m (33 ft) wide, 6 m high, and up to 30 m in length make it the largest of the machines in the contest, and very large by any standards. It is powered by 60 variable speed motors, controlled by Rockwell's PowerFlex variable speed drives, and 18 servomotors, which are controlled by ControlLogix and CompactLogix controllers in conjunction with Kinetix 6000 multi-axis servo drives. The entire control system is tied together with an EtherNet/IP network. The main control cabinet for the machine is about 6 m long.
Another extreme is the high degree of automation. A single operator can virtually run the entire machine, from start to finish, greatly reducing labor costs. This also means no human contact with the meat product, which minimizes the opportunity for contamination. The operator tells the machine what size of sausages to make, and the machine synchronizes all processes, from smoking to packaging to sizing the casings. The company claims labor is reduced by 80%, resulting in a cost savings from 0.12 Euros to 0.40 Euros per kilogram of finished sausage.
Stork Townsend probably made the biggest advance in sausage making when it invented the co-extrusion process in the 1960s. With this concept, meat dough is continuously extruded into a sausage shape and liquid collagen (a natural protein derived from animal skin) is sprayed onto the meat. The collagen forms a gel on the surface which begins to harden into a casing as the newly made sausage rope passes through a brine solution. Stork Townsend says this process can make designer casings to suit customers' taste.
The rest of the process is a material handling operation. The sausages are dropped into baskets that carry them through the pre-drying process, then smoking followed by post drying. The smoke is in liquid form, sprayed onto the sausages. The sausages then enter a packaging stage, where high-speed machinery vacuum packs them. A dedicated ControlLogix system with Kinetix 6000 servo drives manages the six-axis packaging system. Sausages are cooked inside the packages, cooled, and stored for shipment as ready-to-eat (RTE) products.
The whole operation takes one hour, from the start to the finish, to process 2,200 kg of meat.
When Jan Vissers, manager of electronic engineering, began working at Stork Townsend over 30 years ago, the control system consisted mostly of electromagnetic relays. “I was very fortunate that Rockwell launched the Integrated Architecture solutions just at the right moment , when Stork Townsend was in need for such a complete integrated solution.”
Since then, when the company added ControlLogix and HMI in combination with RSLogix5000 and RSView Studio Development software, it has added low voltage switchgear, Intelligent Motor Control (which provides diagnostic data), PowerFlex drives, and Kinetix servo controllers to their systems. Networks used include SERCOS and well as Rockwell's DeviceNet, ControlNet, and EtherNet/IP. Vissers reports that nearly 90% of machines now ship with Rockwell Automation controls.
After two years working with the FactoryTalk Enabled Architecture, Rockwell Automation says Stork Townsend has achieved “the highest possible transparency between controls, HMI, and motion control.”
Michael Babb is editor of Control Engineering Europe . He can be reached email@example.com.