Automation increases speed and accuracy for modified atmosphere packaging

Hyde and Hyde, Inc., Corona, CA, supplies salad components to the fresh-cut produce industry and offers custom packaging and copackaging to its customers. In August, 2008, the company installed a Model PB-1000 servo-driven, 4-wide, modified-atmosphere packaging (MAP) machine from Orics Industries, Inc. (www.orics.com) to run trays for a major fresh-produce supplier. The machine deposits products, such as cranberries, meat, cheese and nuts, as well as a sealed cup of salad dressing, into cavities of the trays, which are sealed in a modified-atmosphere chamber. These trays are shipped to the produce company's plant, where they are matched with a bowl containing fresh-cut produce to provide a one-step meal.

Automation is key

Key to the operation of the Orics PB-1000 system are a number of automation components from Festo Corp. (www.festo.com/us). “We have been working with Festo components for many years, and our customers are pleased with Festo's components because they are durable, easy to use/operate and are affordable,” says Orics president Ori Cohen. “Other suppliers did not offer all of the features and benefits that Festo offers. They provide us with one-stop shopping.”

Orics uses Festo CPX manifolds with DeviceNet nodes, DGPL rodless pneumatic cylinders, DGO magnetically coupled rodless cylinders, DNC rodded ISO-standard cylinders and DSM-CC rotary actuators with hydraulic shock absorbers. It also uses Festo VAD vacuum generators as well as vacuum cups, height compensators, fittings, shock absorbers, sensors and cylinder mounts.

Festo CPX manifolds with the Device Net nodes are responsible for the communication to the host PLC and eliminate Orics' need to hard wire the I/O components on the machine. This reduces labor costs by as much as 70 percent and provides easy installation, service and expansion of I/O modules, manifold bases and valves. The embedded CPX controller enables decentralized or stand-alone control and provides complete diagnostics for fast error detection and easy service.

To start the machine operation, empty trays are vacuum-denested from 4 magazines and drop onto rails. Pushers then move the 4 lanes of trays through the machine. The vacuum for the denesting procedure, as well as for other operations of the MAP machine, is supplied by Festo vacuum generators.

Three weighing systems
The next station in the system is the weighing operation, which weighs the products to be deposited in each tray. The system incorporates 3 weigh stations in series, each of which weighs one product. Each station consists of a 14-head rotary scale system supplied by CombiScale (www.combiscale.com). The Orics MAP machine incorporates an Allen-Bradley PLC from Rockwell Automation, Inc. (www.rockwellautomation.com) and a digital touchscreen with a menu-driven operator interface.

The system maintains in memory the recipes for all of the products that run on the weighing system, as well as the operation parameters of the MAP machine, and the operator can recall them at a touch. When an operator selects a product to be run, the unit automatically sets the operating parameters. The screen also can be actuated to display the settings currently in use, causes of operating problems and maintenance requirements.



Fourteen weigh buckets on each station
The three CombiScale weighing systems are mounted in-line above the MAP machine. Product to be weighed is dumped into floor hoppers, and inclined conveyors deliver it to the weighing systems. On each weighing system, a funnel at the top discharges the product onto a dispersion table that transfers the product to 14 feeder buckets.

These, in turn, move the product by vibration to the weigh buckets. The weigher's computer then selects a combination of buckets (generally 3 or 4) that cumulatively equals the closest weight to the total product weight without being under that weight. The selected buckets then open and discharge their contents down the discharge chute.

The easy-to-use computer-controlled operator interface provides a clear display of charge weight as well as various statistical data. The interface is located on the first floor next to the MAP machine, so the operator can interact without climbing up to the scale. The scale also is designed for easy sanitation by featuring simplified cleaning. Product contact parts are easily removed without tools.

The product from each scale travels down a chute and is diverted into 1 of 2 buckets, each of which, in turn, discharges into 1 of 2 buckets on the next level. These discharge into 4 buckets that deliver products into the trays. When product has been delivered to all 4 trays in the row, that row of trays is pushed to the next station, while the next row of trays is pushed into the weighing zone. The system incorporates 30 Festo DSL-CC rotary actuators to open and close the buckets. Orics also uses Festo DGO actuators to lift the trays as product is being deposited.

Vertically reciprocating arm places cups in trays  

The next station after weighing is the placement of filled and sealed cups of salad dressing into the fourth cavity in each tray. A worker manually places the cups on a rotary table that delivers them onto a conveyor that carries them into the filler/sealer.

Two Festo DGPL rodless cylinders move an arm with vacuum cups over the cups of salad dressing on the infeed conveyor. The arm is moved downward by 2 Festo DNC rodded cylinders and picks up 4 cups. The arm then rises and moves over the trays, where it descends and places the cups in the proper cavities.

The filled trays are pushed into the next zone of the machine, while the arm with the vacuum cups travels back to its starting position to pick up the next group of dressing cups.

The trays are then pushed, one row at a time, into the MAP heatsealer. After a row of trays are in the chamber, it is latched closed, the air is evacuated and the chamber is flushed with a specific computer-controlled, constant-flow gas mixture that is tailored to the products being run.

Next, film is heat-sealed across the tops of the trays. The film is die-cut as it is sealed, and waste is automatically collected on a quick-release drive. The chamber is then opened and the 4 trays are lifted and pushed onto a discharge conveyor.

Outstanding suppor

t

"Festo's service and technical support have been outstanding,” says Cohen. “Its district sales engineer, Bill Uihlein, is very knowledgeable, very creative and is always there for us. The Festo products are reliable and provide us with the precision we require for our equipment, and the catalog and the information provided on the Festo website are user-friendly, detailed and organized.”