Maximizing efficiency in high-speed multipack shrink wrapping

The latest technology in high-speed shrink wrapping allows vertically-oriented multipacks of bottles, cans, canisters and jars to be automatically wrapped directly after filling while in an upright position, without any manual intervention. 

The popularity of multipacks is universal. Once found only in club stores, multi-item packaging is ubiquitous wherever packaged goods are sold. The reasons for this are obvious – combining several items in a singular package has multiple benefits to manufacturers, retailers and consumers. Consumers can capitalize on special packaging promotions for a reduced cost per item, purchase different forms of the same item in one variety pack, and they provide convenience in carrying several items. For manufacturers and retailers, multipacks promote a larger unit of sale, keep products cleaner, help prevent package pilferage, and reduce environmental impact by using less secondary packaging.

Multipack packaging exists in a number of formats including paperboard baskets, paperboard overwraps and cartons, corrugated fiberboard boxes, high-density polyethylene plastic handles, six-pack rings and shrink packs. The demand for shrink wrapping multipacks has particularly grown in application as a way to reduce the amount of packaging material needed, both to cut packaging costs and to better achieve sustainability initiatives. But shrink wrapping multipacks of vertically-oriented containers such as bottles, cans, canisters, jars, boxes and aerosols poses significant challenges for manufacturers.

Inefficiencies in Shrink Wrapping Vertically-Oriented Containers for Multipacks

In a conventional multipack shrink wrap set-up for wrapping vertically-oriented products, once the containers are filled, they must then be laid down on their sides on a conveyor and manually turned so that their logos are facing in the same direction and/or their barcodes are hidden. The only practical way to hold the items together to keep them from rolling while being wrapped is to use a chipboard carrier tray or "boot". They are then fed through a horizontal shrink wrapper which applies a polymer plastic film, and when heat is applied it shrinks tightly over whatever it is covering. 

Because the manual manipulation of the products is done off-line, many manufacturers prefer to send out the individual containers after filling to contract packagers and have them orient the products and shrink wrap them into multipacks. In essence, the manufacturer fills the containers, sometimes wraps them, boxes them, palletizes them, ships them to a contract packager who takes the individual containers out of the boxes and puts them on a conveyor along with a carrier tray, orients the positioning of the containers so the logos and barcodes are in the proper position, then shrink wraps them in multipacks, boxes, palletizes and sends them back to the manufacturer for distribution or to an external distribution center.

This method not only adds additional costs, labor and time to the packaging process, but also necessitates the use of added packaging materials from the carrier trays and film for double wrapping. Add to this the increased consumption of energy for additional transportation and the double wrapping and cartoning, making for a very inefficient system.

Packagers have been in need of a way to shrink wrap these vertical-product multipacks without the added labor and expense from conventional horizontal shrink wrapping systems.

New Technology Enables Upright Product Positioning

The latest technology in vertical shrink wrapping eliminates these problems.  Most critically, they can automatically wrap multipacks of products such as bottles, cans, jars or canisters directly from the fillers with the product standing upright. With no need for manual re-orienting of the products prior to wrapping, containers can now go directly from filling to wrapping to cartoning to distribution in-line, without interruption. Additionally, carrier trays are no longer required to position the individual containers for shrink wrapping with this latest technology.

One such system, the patent pending 914 Orbital Vertical System® (OVS) from Texwrap (www.texwrap.com), which designs and manufactures fully-automatic shrink wrapping systems, not only automatically wraps containers while in vertical positions, but the wrapper trims the film underneath the package, where it is hidden from view. This offers many more packaging opportunities for packaging designers, and does not compromise product presentation on store shelves. Using an exclusive patented mechanism, it cuts and trims away the film in one action to create a full bottom trim seal, instead of the traditional lap seal, to enclose the product.  This makes a very secure and attractive package for store display. 

The sealing is done with a servo orbital-motion head. It eliminates the need for the head to move with the product while the seal is being made. The head moves in an ellipse, without the back and forth motion of typical sealing heads, which dramatically increases the throughput speed of the wrapper.

The servo-technology was designed from the ground up to integrate servo-motors, PLC controls and the mechanical elements of the system. The servo-controls give precise product and film control which allows high-speed wrapping with precision print registration. The result is a fast, reliable and flexible wrapper with minimal moving parts and maximum performance, capable of wrapping 150 three-container multipacks per minute while using the least amount of film possible.

Automated Container Orientation

To make this new vertical shrink wrapping technology even more effective, a multipack of vertically-oriented products can be automatically arranged with the labels facing precisely in the same direction while standing upright, before shrink wrapping.

Texwrap uses high-speed camera technology to scan each item as it enters the system. Camera data is transferred to the controller, resulting in exact movement information to obtain the desired final product orientation. Servo-driven gripper wheels spin each container to this position resulting in precisely aligned labels for a strong point-of-sale visual presence. This makes a very attractive and functional multipack. 

This system is also flexible enough to orient multiple UPC codes in a variety multipack.

Hiding Barcodes

An important function in packaging of multipacks is to cover the barcodes of the individual cans or bottles, so that the package can be identified as a multipack and not as individual units.

The servo-precision of this new vertical wrapping technology ensures that the individual container barcodes can be covered by printed film.

Because this wrapping technology does not require a carrier tray to hold products in place while wrapping, in applications where the carrier tray was also used to hide bar codes from individual containers, the packager can now use printed film to correctly identify the unit as a multipack.

Focus on Flexibility

This latest technology in vertical shrink wrapping enables a significant leap in performance for those companies desiring to streamline their packaging lines.  Reduced labor, material usage and operating costs. Faster cycle times and higher throughput.

But this new technology also affords manufacturers a wide latitude of flexibility to design and set-up shrink packaging lines to custom fit their specific requirements for wrapping vertically-oriented products. A capability that can, possibly for the first time, make their vertical-product packaging lines a showpiece of efficiency and ROI.

Jim McMahon writes on packaging automation. His feature stories have appeared in hundreds of industrial and high-tech publications throughout the world and are read by more than 5 million readers monthly. He can be reached at jim.mcmahon@zebracom.net