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Whether it’s a printing press machine or a packaging and filling machine, motion control suppliers have just what it takes to create the right solution.
Packaging and labeling, especially in the food industry, is a fast-paced and constantly changing landscape. Amid the cluttered shelves in grocery and convenience stores, manufacturers vie to attract consumers’ eyes to their products. That means using increasingly decorative and highly graphic labels and innovative packaging shapes. At the same time, shoppers today expect more nutrition and other information on labels than ever before.
Fig 1: The ELS-D inline printing press from PCMC is outfitted with servomotors and control equipment from Rockwell Automation.
These market realities put pressure on packaging machine designers. It means that label printers must be ready for changes every day, and their printing presses need to be versatile enough to turn out multiple types and sizes of labels and packaging. Printing presses also must run at high speeds, while allowing operators to quickly and easily program machines to change from one product to another.
One example of the need for adaptable printing presses is the lowly ketchup bottle. Ketchup packaging has evolved from bottles with simple labels to highly graphic sleeves shrunk over eye-catching containers. A similar story holds true for nut snacks and pet treats. Other products once packaged in large bags now come in resealable pouches, with attractive graphics printed on the package.
One company, the Paper Converting Machine Company or PCMC, was tasked with delivering a new printing press, named the ELS-D. Engineers at PCMC needed to improve its performance while converting the control platform to better meet specific customer requirements. Namely, their customers wanted a flexible machine that was capable of fast, easy and frequent product changeovers throughout the day. The machine should let operators input a new recipe quickly and easily without changing machine parts each time.
PCMC machines are standardized on one platform so end-users only need to train their staff on one platform. Standardization on a common control platform also allows engineers at PCMC to re-use application code from one machine to another, reducing development and troubleshooting time. This common platform also allows PCMC to share engineers across project teams so when one area is particularly busy, engineers from another area can easily be brought in to help.
The PCMC engineers replaced the traditional plate gear drive system with dual Allen-Bradley® MP-series™ medium inertia servo motors, enabling precise motion control and fast product changeovers. The addition of servo motors to the press allowed for an infinitely variable repeat so operators can easily command multiple product changeovers throughout the day, each with the touch of a button. The motors also can withstand high-pressure and caustic wash-downs, making them more reliable than the previous gear drives.
The engineers integrated the MP-series servo motors with Allen-Bradley Kinetix® 6000 and 6200 servo drives to allow easy speed and position adjustment. An integrated display computer with a Windows embedded operating system, touch screen and RSView® Machine Edition human-machine interface software lets you easily select a specific print-repeat size for each type of package label.
The machine also uses an Allen-Bradley ControlLogix® L73 programmable automation controller, or PAC. The ControlLogix L73 features an integrated platform for motion and machine control and a single programming environment, which among other benefits reduces the number of spare parts to maintain.
The new system allows operators to more easily operate and maintain the machine than with the previous gear drive system. Now the controls and drives platform is familiar to customers, as well as PCMC engineers and service technicians.
Unlike the previous gear drive system, the ELS-D inline printing press can print any print repeat size between minimum and maximum with a simple numeric input on the operator screen. The previous mechanical gear drive system required the customer to print a repeat by changing the machine gearing, which limited the amount and type of products able to be printed on the press. Now the customer can use the servo-driven printing press for food and beverage product labels as well as pharmaceutical labels.
“Gone are the days when package printers can purchase one machine for each type of product label,” said Mike Jarmuskiewicz, new product development leader with PCMC. “With an increasingly competitive environment on store shelves, manufacturers need to make many different variations of one product type. The ELS-D inline printing press can handle any type of label and quickly change from one label to another multiple times per day.”
Equally important is the ability to pre-program different product changeovers. This significantly reduces waste when an operator is setting up each print job because the machine is already programmed for a certain web width and material length. “The operating system also allows the operator to recall a print job from earlier in the day or the day before, which saves time and reduces material waste,” Jarmuskiewicz said.
Packaging and Filling
Packaging machine builders continue to develop new technologies that boost product throughput and lower costs for their customers. One such technology, recently developed by Cloud Packaging Equipment Co., is designed to ensure both fast and accurate filling of pouches and cartons. For speedy and precise carton movement, the carefully designed cartoning portion of Cloud’s new system relies on a pair of MXB belt-driven actuators from Tolomatic Inc.
The Performa SP packaging system is a horizontal form-fill-seal (HFFS) pouch machine that makes plastic bags out of a flat roll of plastic film, then fills the bags with product and seals them. The system can process up to 4,500 pouches per minute.
At the end of the Performa HFFS process, a transfer wheel allows an exact count as filled pouches are dropped into cartons. Pouches follow a carton as it indexes to complete the desired count. When one carton is filled, pouches start dropping into the next unfilled carton.
The higher speed of the new machine also required a new carton staging and feed system, because the actuators used in the carton staging and feed timing are critical to ensure accurate and consistent package counts per carton.
Key components of the cartoning system include two actuators, one for the initial positioning of each carton and another to move cartons through the fill zone. Cloud engineers received help in choosing these actuators from Flow Products Inc., a Chicago-based Tolomatic distributor that develops and sells hydraulic, pneumatic and electromechanical equipment.
The design team initially considered ball-screw actuators for the system, but eventually determined that belt-drive actuators were a better choice because the belt-drive units needed to meet the application’s thrust and acceleration requirements were much smaller and more cost-effective than ball-screw actuators with similar capabilities.
Once Cloud engineers decided to use belt-drive actuators, the next step was choosing an actuator for the system. The engineers initially considered actuators produced by several manufacturers. While there were similarities among all these actuators, Tolomatic units stood out because of their larger input shafts, oversized pulley bearings and consistent repeatability. Tolomatic’s MXB belt-driven actuators deliver consistent position repeatability of ±0.002 in. (±0.5 mm). A calibration process in which initial position error is determined and then eliminated through programming ensures precise positioning accuracy.
Fig 2: A cutaway view of the MXB belt-driven actuators shows the inner workings of the actuators.
“I was surprised that a number of manufacturers use extremely small input shafts and bearings for this application,” said James Sybeldon, a senior project engineer at Cloud involved in the design of the new packaging technology. “I felt more comfortable with the Tofihe servo motor in our machine was capable of delivering.”
The engineers thought the Tolomatic MXB-P guided belt-drive electric actuator was a good fit for the Performa SP based on a few key features including a rodless design that takes up less space than rod-style actuators, lightweight aluminum construction optimized for rigidity and strength, and a profiled rail bearing system to reduce friction and extend actuator life.
In Cloud’s cartoning system, one MXB-P actuator, with a 16-inch stroke length, positions each carton at the starting point of the fill zone. The other actuator, with a 25-inch stroke, feeds the carton at the precise speed required to ensure that it contains an accurate count of pouches as it exits the system.
Fig 3: The bottom view of the Performa SP packaging system from Cloud Packaging Equipment Co. shows the pair of MXB-P belt-driven actuators from Tolomatic Inc., that drive the cartoning portion of the machine.
On the Performa machine, the MXB-P actuators work with servo motors to provide both the speed and positional accuracy required by the cartoning system. The servo drives also allow carton size and fill count to be changed through programming, which is quicker and easier than making mechanical changes to linkages or conveyor sections. “With programmable servo drives, we can develop a set of motions that work for a particular product, and then save that information so the system can set itself up the next time we run that product,” said Sybeldon.
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Rockwell Automation
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