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The perfect pita packer

The perfect pita packer
Marginal Column

July 2015


Kangaroo Brands Inc. packages seven types of sandwiches in cartons of four different sizes. To achieve both quick changes from one product to another and a high throughput rate, the company uses a packaging machine featuring Rexroth automation.

When Kangaroo Brands Inc., located in Milwaukee, Wisconsin, USA, began offering pita bread and sandwiches, they were packed individually, by hand, with no mechanical support. But large retailers like Walmart soon became aware of the tasty snacks – and order receipts showed a month-by-month rise. “In serving the larger retailers and club stores, we had to begin packaging our pita sandwiches in different count cartons,” said Justin Rice, Kangaroo plant manager. The company uses four different carton sizes, with capacities ranging from four to 14 sandwiches.

Responding to the rising complexity and number of cartoning cycles, Kangaroo Brands decided to invest in an automated cartoning system. It was to make the change between different carton sizes both quick and effective. In addition, it was to be installed in limited space, without any interruption in production. It was with these specifications in mind that Rice turned to Ultra Packaging Inc. “We have a long-standing relationship with Ultra Packaging and have purchased other machines from them, so when we decided to automate cartoning we took their Veronica machine into consideration.”

Less cabling, lower costs

Ultra Packaging had designed this seven-axis machine for applications requiring great flexibility and quick changes of formats. The Veronica erects cartons from flat paperboard blanks, moves them to the stations where they are filled by staff members, and then closes and glues the cartons. The IndraDrive Mi platform made by Rexroth is responsible for smooth, trouble-free processing. Each axis in the machine is moved with its own integrated drive. These units comprise a Rexroth servo motor with the drive electronics integrated into the motor housing. In this way, the drives can be installed directly in the machine itself and no longer require any space in the control cabinet. This also lowers both the cooling requirements for the cabinet and the parts costs for the machine as a whole. A single cable handles both power and communications, running from the power supply in the control cabinet to the first IndraDrive Mi. From there it is daisy-chained to the other IndraDrive Mi units.

“By using Rexroth’s IndraDrive Mi concept, we reduced our linkages and other machine components by 60 percent compared to prior models,” explained Bob Stockus, vice president at Ultra Packaging. “Our cabling costs have gone down about 40 percent and our time for field wiring alone has dropped 40 percent.” At the heart of the machine is an L25 motion-logic controller, which governs synchronous movement at all the axes. The IndraMotion MLC is a highly developed automation platform offering a wide range of non-proprietary interfaces. The Veronica cartoner uses Sercos III to ensure precise and efficient synchronization of the servo drives as well as control of various machinery functions.

Quick carton changes

In the course of the process chain at Kangaroo, an inclined conveyor belt moves the sandwiches, having been packed in two flow wrapping machines, to the height of the conveyor belt for the Veronica. There, members of staff stand at eight packing stations and lay the sandwiches in the boxes which were previously erected by the machine. Once a carton is full, it is closed by the Veronica. According to Rice, one of the key reasons for choosing this machine was the simplicity of making the change to a different carton size. “During a typical work week, we may perform 16 to 18 carton changeovers for various customers. It typically only takes 10 to 15 minutes to do, and we’ve trained four different associates to use the touchscreen Human Machine Interface (HMI) to do the changeover.”

These controls, using the Rexroth VCP 35 terminal with a 10-inch color screen, are based on the L25 motion-logic control unit. IndraWorks is used to program it. This allows the operators to control not only the Veronica itself, but also the conveyor belts that move the products along. Thanks to the modular design of the IndraDrive Mi, new axes can be added to the machine with minimum effort. Another reason for choosing the Veronica was its compact footprint, since the space available in the production building at Kangaroo is limited. That is why Ultra Packaging integrated the controls for the conveyor belts into the controls for the Veronica.

240 sandwiches per minute

The automated packaging process has made it possible for Kangaroo to increase its output significantly. Today, about 240 sandwiches per minute are packed in cartons that differ in dimension. “And if Kangaroo needs to increase throughput in its cartoning processes, the Veronica has the capacity,” Stockus said. “It leaves a lot of room for future growth.” The investment has already paid off for the company. “By adding the Veronica, we were able to reduce operating costs by 150,000 dollars per year,” says Rice. “The solution has been performing at or above our expectations and production targets are consistently met. The Veronica cartoner, with the Rexroth drive and control platform, is an effective approach to meeting the requirements of our rapidly changing production environment.”