Guide screw key for packaging upgrade

Rapid guide screw helps maker of high-quality container handling and packaging equipment increase flexibility of shrink bundlers.

Omega Design makes high-quality container handling and packaging equipment.

The list of equipment produced by the Exton, Pennsylvania-based company includes plastic bottle unscramblers, puck unscramblers with container placement, shrink bundlers, stretchbanders, tray shrink packaging systems, wrap-around case packers, secondary orienters, canister desiccant feeders and specialty equipment.

The markets served by the equipment covers the pharmaceutical, personal healthcare, cosmetic, food, beverage, dairy and chemical industries.

One of the company's flagship products, the Classic series of shrink bundlers, has gained a particularly stellar reputation.

Hundreds of units have been sold and are in operation throughout the world.

This pneumatically-driven, PLC-controlled machine was designed for automatic shrink or stretch packaging of glass, plastic or metal containers, boxes or cartons into pre-determined bundle configurations.

The design of the Classic helps eliminate the high cost of cardboard boxes and creates a more efficient, secure package, which lends itself to further automation down the line, such as case packing.

Omega wanted to enhance the performance of the shrink bundlers.

After incorporating several other machine upgrades - resulting in a 50% increase in output - the company focused on the product pusher, a pneumatic-driven actuator that literally pushed the product into the film or other packaging material.

Inherent in this 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.

This was proving to be a difficult proposition with the current pneumatic system, because the uneven motion control produced inconsistent product flow through the pusher area, and could cause the products to become misaligned, creating a machine stoppage.

Stoppages result in downtime, which translates to a loss of profits.

"Frequent changeovers on a packaging line often require you to stop production for retooling, sometimes taking up to several hours", said Devendra Shendge, Product Development Specialist with Omega Design.

"We needed an intelligent yet cost-effective method that could handle a variety of packages".

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 our machines, the better", said 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.

It also needed a method 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.

Omega engineers turned to Kerk Motion Products, a manufacturer of non-ball lead screws.

After discussions with applications engineers and a examination of the company's offerings, Omega saw promise in the Kerk RGS (Rapid Guide Screw) 10000, a screw-driven slide that offers linear speed, accurate positioning and long life in a compact assembly.

While the RGS is not an actuator, Omega used it as the centrepiece of a new assembly.

Omega's product development engineers worked with Kerk to incorporate a servo motor and a few additional components, to create an intelligent motion product 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 retrofittable to the unit we were already using, easily meeting the machine's space constraints".

The length and speed of the RGS is not limited by critical screw speed, allowing high rev/min and linear speeds, even over long spans.

Standard leads include 0.254, 0.508, 1.27 and 2.54cm travel per revolution.

With Kerk's range of available leads, speeds over 1.5m/s are possible, rivaling belts and cables while offering better positioning accuracy, repeatability and axial stiffness.

The RGS includes a precision aluminium guide and carriage and is driven by a precision rolled stainless steel lead screw.

The moving surfaces include Kerkite high performance polymers running on Kerkote TFE coating.

It has a compact profile that provides torsional stiffness and stability for its size and weight.

The integral mounting base allows support over the entire length if desired.

It also comes standard with a wear-compensating, anti-backlash driven carriage.

Using the RGS, Omega has produced a machine with benefits for both Omega and its customers.

The bundler demands less maintenance and requires less labour to maintain.

There have also been cost savings, as less labour is needed to assemble the machine and there are fewer components.

"Before it was just a continuous motion, 0-130cm/s", said Shendge.

"Now we can accelerate or decelerate the machine".

"This is critical, because when you're dealing with some of 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, and thus accommodate alternative package shapes.

"Plus", said Shendge, "we can take the feedback from this intelligent motion and use it to improve the overall operation of the machine".

Shendge also said that in the original testing, the RGS 10000 was generating 68kg of force, while the original air cylinder only produced 36kg.

Omega first purchased an RGS 6000, but it was too small to do the job.

Omega asked Kerk for a bigger unit; one did not exist at that time, Kerk explained, 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", said Shendge.

"Kerk was able to meet 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".

Omega wasn't the only company impressed with the results.

"At the show, Omega had the Classic shrink bundler with the intelligent pusher on exhibit for the first time", said Shendge.

"A manufacturer of personal care products saw the machine at the show, and installation of the new machine should occur in the next few months".

"We had quoted them with the original actuator, but they liked it more with the Kerk unit".

Shendge also said Omega had received a number of requests for RGS 10000 upgrades to existing bundlers, and provided several quotes for upgrades from the trade show inquiries alone.

Multiple upgrade installations for existing users are planned soon.

"We're still in the evaluation phase, but I suspect that the RGS 10000 will be standard for the Classic SL-18", said Shendge.

Upgrades to Omega machinery do not stop at the bundler's pusher unit.

Kerk is designing an actuator with a round shaft.

Omega is considering the use of these 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 into our equipment", said Shendge.

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