Servo system speed production

By Edited by Jack Mans, Plant Operations Editor in Automation on August 31, 2008

When you're in the business of providing sauce packs and cups for major fast-food suppliers, speed is of the essence. Stop and consider how many condiment packs are produced in a given week to serve the market.



Mullins Food Products, Broadview, IL, develops, manufactures and packages the condiments found in many leading fast-food restaurants. Its product line ranges from ketchups, mustards and barbecue sauces to mayonnaise, salsas and other dressings and blends. The company produces a large volume of packets, so any speed improvement in the packaging line can lead to noticeable results. With this in mind, Mullins examined its entire production process and identified specific areas where speed and efficiency could be improved. One area immediately identified for improvement was in the way it packages its dipping-sauce cups into larger cases for shipping. The final packing area of the line largely determined the overall speed of the line.

Servo-driven pick and place The case packer picks up 50 cups during each cycle and places them into the shiping case. It packs 250 cups 
(five layers) into each shipper and places a slipsheet between each layer

To better meet its customers' demands for 1-oz cup products, Mullins decided to commission a new case-packing machine capable of quickly picking and placing the cups in cases for distribution. It purchased a high-speed, three-axis case packer made by Soleri Design/Automation, Inc. (www.soleridesign.com) equipped with a high-performance servo system from the Electric Drives and Controls group of Bosch Rexroth Corp. (www.boschrexroth-us.com/brc). As another option, Soleri Design/Automation also offers a robotic style three-axis case packer with a smaller footprint.



Designed to accelerate speed across the entire production line, Soleri's case packer and its Rexroth components integrated seamlessly with an upstream, previously installed cup-filling machine from Winpak Lane, Inc., (www.winpak.com). With this integration, Mullins significantly accelerated the overall speed of its cup line.

After filling, the 1-oz cups travel down the production line toward a case-packaging area, where 50 containers are picked up with a suction head that orientes them and places them into the shipping case. While one group of cups is being placed in the shipper, a separate pickhead places a paperboard slipsheet between each layer of cups to add strength and to ensure the cups are not damaged during shipment. Each case contains 5 layers, providing a total of 250 cups/case.

The machine is driven by Rexroth intelligent IndraDrive digital servo drives and Rexroth MSK servo motors. The high-performance servo drives offer many advanced features, including distributed intelligence to all the loops in the drive, which frees up the controller to calculate and execute the pick-and-place path planning. The drives also provide a 230- to 480-volt alternating current, auto-ranging input voltage, absolute feedback to eliminate homing and a built-in SD memory card for laptop-free replacement in minutes. The compact design of the drive amplifiers allows the use of standard 12-in. cabinets for a smaller machine design.

In additon to increased production, waste has been significantly reduced.

A key component of the system is the high-performance Rexroth motion and logic controller that resides upstream on the Winpak cupmaking machine. This compact, rack-based system synchronizes all of the servo motions and controls on both the Winpak cup machine and the Soleri case packer. As a result, the speed of each machine directly corresponds with the tempo of the other one. For example, if the Winpak machine ramps up its production to 65 cycles/min, the Soleri case packer will seamlessly adapt to handle the volume.



To help with the control specifications, Soleri relied on its 10-year relationship with its local Rexroth automation distributor, Applied International Motion (www.aimotion.com [AIM]).

When discussing possible specifications with Soleri, AIM's Dan Dal Colletto determined the most beneficial architecture from the Rexroth family of electrical, mechanical and pneumatic product lines. AIM helped Soleri by coming up with an optimal electric-controls architecture, as well as a ball-screw unit for vertical actuation. As a result, Soleri was able to use smaller servos, keeping the machine footprint to a minimum, while still achieving the overall speed increase it was seeking.

The compact design of the drive amplifiers allows the use of standard 12-in. cabinets for a smaller overall machine design.

“The Rexroth control components simplified the entire process,” says Richard Soleri, the equipment company's owner. “With its high-quality components and applications-engineering support, it helped to optimize the system for what Mullins wanted to achieve.”



It didn't take long for Mullins to reap the rewards of the Soleri case packer. In an industry governed by speed, the Soleri machine immediately produced a sizeable increase in cycle speed, according to Mullins maintenance manager, Larry Coons.

“In terms of calculating production, we are ultimately measured by cycles/minute, and with this case packer, our throughput times have accelerated nicely,” says Coons. “Prior to the installation of the Soleri machine, we maxed out at around 58 to 60 cycles/min. We're now running at least 70 cycles per minute; about 17 percent faster production. The case packer has provided exceptional performance for us. We will eventually convert more case packers to servo technology, because we've witnessed such a significant increase in production.”

Production volume isn't the only thing that improved. Coons says that package and product waste have improved also. With the servo system, the machine is moves slightly slower while the cups are enroute to the shipper, but faster on the return to pick up more cups. This controlled action reduces lost or damaged products; a number that Coons says has dropped by nearly 10 percent.

With the successful installation of its Rexroth-equipped Soleri case packer, Mullins is pumping out sauces and condiments much faster, and has the ability to go even higher. So the next time you're eating at your favorite lunch stop, don't hesitate to request another cup of sauce. Mullins Food Products will help ensure there's always more available.





More information is available: Bosch Rexroth Corp. 847/645-3600. www.boschrexroth-us.com/brc. Applied International Motion, 909/593-7304. www.aimotion.com. Soleri Design/Automation, Inc., 805/494-1187. www.soleridesign.com. Winpak Lane, Inc., 909/386-1772. www.winpak.com.



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