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New motion-control solution saves a 'bundle'
January 29, 2014
8 Min Read
Recognized as an industry leader for more than 30 years, Omega Design Corp. (www.omegadesign.com) manufactures a broad range of high-quality container-handling and packaging-equipment systems. The list of equipment produced by the Exton, PA-based company includes plastic bottle unscramblers, puck unscramblers with container placement, shrink bundlers, stretch banders, tray shrink-packaging systems, wraparound case packers, secondary orienters, canister-desiccant feeders and specialty equipment. The wide range of markets served by Omega equipment is equally noteworthy, with installations in the pharmaceutical, personal care, healthcare, cosmetic, food, beverage, dairy and chemical industries.
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One of the company's flagship products, the Classic Series shrink bundler, has gained a particularly good reputation. Hundreds of units have been sold and are operating throughout the world. This pneumatically driven, PLC-controlled machine was designed for automatic shrink or stretch packaging of glass, plastic and metal containers, as well as boxes and cartons, into predetermined bundle configurations. The design of the Classic series helps to eliminate the high cost of paperboard boxes and creates a more efficient, secure package, which lends itself to further automation down the line, such as case packing.
In the spirit of constant improvement, Omega continually sought to enhance the performance of the Classic shrink bundler. After incorporating several machine upgrades, which resulted in a 50-percent increase in output, the company focused on the product pusher, a pneumatically driven actuator that literally pushed the product into the film or other packaging material. Inherent in this pneumatically driven actuator was excess play and uneven motion control, resulting in increased setup time and maintenance.
But that was just the tip of the proverbial iceberg. With many of Omega's customers increasing their demands for unique packaging, the company needed to accommodate an increase in alternative package designs, sizes, materials and configurations. Meeting this demand was difficult with Omega's current pneumatic system, because the uneven motion control produced inconsistent product flow through the pusher area. This could cause the products to become misaligned, creating a machine stoppage that resulted in downtime and a loss of profits.
"Frequent changeovers on a packaging line often require you to stop production for retooling, sometimes taking up to several hours. We needed an intelligent, yet cost-effective, solution that could handle a variety of packages," says Devendra "Win" Shendge, a product-development specialist with Omega Design.
Additionally, Omega needed to reduce the amount of air being used in the existing version of the machine. "The more air we can take out of this or any of our machines, the better," says Shendge. "Air can be expensive, and the existing actuator system used quite a bit of it."
Omega needed an actuator that would produce higher speeds, yet would have intelligent motion-control capabilities to accommodate a broad spectrum of product dimensions. The company also needed a solution that would require little or no maintenance, and one that would greatly reduce the use of costly air, as well as the occurrence of air leaks.
In a quest for a new solution, Omega engineers contacted numerous suppliers and scanned the design trade magazines, before coming upon an advertisement for Kerk Motion Products (www.kerkmotion.com), a leading manufacturer of non-ball lead screws. After discussions with applications engineers and a thorough examination of the company's offerings, Omega saw tremendous promise in the Kerk RGS(TM) (Rapid Guide Screw) 10000, a new screw-driven slide that offers exceptional linear speed, accurate positioning and long life, in a compact, value-priced assembly.
While the RGS is not an actuator, Omega, relying on its penchant for innovation, used the RGS 10000 as the centerpiece of a new assembly. Omega's product development engineers worked with Kerk to incorporate a servo motor and a few additional components, to create a revolutionary new intelligent motion solution that would replace the existing pneumatic system. The easy insertion of the RGS 10000 made the unit even more attractive. "It was a simple swap-out," said Shendge. "Kerk's RGS was retrofitable to the unit we were already using, easily meeting the machine's space constraints."
The length and speed of the Kerk RGS is not limited by a critical screw speed, allowing high RPM and linear speeds, even over long spans. Standard leads include 0.100, 0.200, 0.500 and 1.00 in. of travel per revolution. With Kerk's wide range of available leads, speeds over 60 in./sec (1.5 m/sec) are possible, rivaling belts and cables, while offering positioning accuracy, repeatability and axial stiffness.
The Kerk RGS includes a precision aluminum guide and carriage and is driven by a precision rolled-stainless-steel lead screw. The moving surfaces include Kerkite(R) high-performance polymers running on a Kerkote(TM) trifluoroethylene coating. The RGS has a unique, compact profile that provides exceptional torsional stiffness and stability for its size and weight. The integral mounting base allows support over the entire length if desired. The Kerk RGS 10000 also comes standard with a wear-compensating, anti-backlash driven carriage.
Using Kerk's RGS 10000, Omega Design has succeeded in producing a new machine with benefits for both Omega and its customers. The new bundler demands less maintenance and requires less labor to maintain. Omega has also realized significant cost savings, as less labor is needed to assemble the machine, and it has fewer components. No longer will Omega or its customers need to stock various sensors and pneumatic parts, which have been replaced by the intelligent actuator.
"Before, it was just a continuous motion at zero to fifty in./sec," said Shendge. "Now we can accelerate or decelerate the machine. This is critical, because when you're dealing with the unusual shapes and heavier mass of some products, you can't just thrust them through the machine at top speed. You can damage the machine as well as the product." Additionally, changeover time between products has decreased, since the machine can be programmed to adjust to various products through recipe-driven settings that are specific for each product's handling needs. Thus, it can accommodate alternative package shapes. "Plus," says Shendge, "we can take the feedback from this intelligent motion and use it to improve the overall operation of the machine."
Shendge also says that, in the original testing, the RGS 10000 was generating 150 lb of force, while the original air cylinder only produced 80 lb. Omega first purchased an RGS 6000, but it was too small to do the job, so Omega asked Kerk for a bigger unit. Kerk explained that a bigger unit did not exist at that time, but it was in the process of tooling up for the RGS 10000.
"We told Kerk to start making it fast, before the PACK EXPO show, where we were exhibiting the Classic," recalls Shendge. "Kerk met our deadline, and we were able to get the RGS 10000 into one of the bundlers at the show. So we actually purchased the very first one."
We can take the feedback from this intelligent motion and use it to improve the overall operation of the machine.
Omega wasn't the only company impressed with the results. "At the PMMI PACK EXPO show, Omega had the Classic shrink bundler with the intelligent pusher on exhibit for the first time. A manufacturer of personal-care products saw the machine at the show, and installation of their new machine should occur in the next few months," Shendge says. "We had quoted them with the original actuator, but they liked it more with the Kerk unit."
Shendge also indicates that Omega has received a number of requests for RGS 10000 upgrades to existing bundlers. In fact, he says that Omega has provided several quotes for upgrades from the tradeshow inquiries alone, where the RGS 10000 was introduced. Multiple upgrade installations for existing users are planned in the near future. "We're still in the evaluation phase, but I suspect that the RGS 10000 will be standard for the Classic SL-18," he says.
Upgrades to Omega machinery do not stop at the bundler's pusher unit. Kerk is currently designing a new actuator that features a round shaft. According to Shendge, Omega is considering the use of these new actuators to replace the remainder of the pneumatic cylinders on the machine.
"We look forward to continuing our relationship with Kerk, and incorporating additional intelligent motion control solutions into our equipment," explains Shendge.
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