As the oldest company in the United States commercially making pocket bread, Teeny Foods, Portland, ore., holds the patent on this increasingly popular bread. Bet after 30 years, the company outgrew its first production facility.
The solution was to move into a new plant with updated automation controls. After only a few months the new facility allowed the company to double its production of pita bread and to make a more consistent product. The plant now bakes up to 20,000 pieces per hour.
"We simply outgrew our old facility," said Rick Teeny, president of Teeny Foods. "We needed more space, but we also wanted to improve our production process."
Company goals were to reduce product imperfections, increase production, improve process control and reduce the number of employees while maintaining high quality standards. "At the new plant, we added variable-speed motor control and integrated the controls with OEM equipment so we could communicate on one network to coordinate production throughout the plant," Mr. Teeny added. "In the long run, the new system will dramatically reduce our cost per piece."

Production Process
Vital to this improved productivity was equipping the company's separate sheeting and baking/cooling production lines with Allen-Bradley Bulletin 160 Smart Speed Controllers to regulate AC-Motor speed on the production conveyors. The compact motor controllers allowed variable-speed operation to help match process requirements, such as longer baking or cooling times, that are critical for product formation and proper baking. Because Teeny Foods bakes more than 200 different flat bread variations, it is very important for the company to reliably match requirements in all areas of production."
The sheeting line takes raw, bulk materials and formulates sheeted products, ready for baking. Each formulation has a slightly different dough thickness and shape. Large chunks of dough are manually transferred from the mixing station onto the sheeting line where they are converted to specified thickness and width.

Speed is Critical
This section is where accurate speed control is especially critical, because if the dough is not the right thickness, it will not bake correctly. The conveyors and process devices on the sheeting line are tied into a DeviceNet network that allows Teeny Foods to monitor and control the line as well as communicate between devices. Allen-Bradley 160 SSC controllers synchronize the speed of the conveyors and rollers for the appropriate dough thickness and weight before it reaches the cutting station, located near the end of the line.
After it is cut, dough is placed on specially designed trays to be proofed. Here again, precise conveyor speed is important to synchronize transfer of the dough from the conveyor onto the trays. Precise speed coordination and conveyor control reduces dough wastage.

Oven Line
After proofing according to product needs, the dough trays are loaded onto the oven line. The dough is then transferred from the proofing trays onto the oven conveyor.
Baking is the most important phase of Teeny Foods' production. Without proper control of baking time and temperature, the bread's pocket won't form, and the loaf may be undercooked or burned. Here again, the speed controllers regulate how fast the product passes through the oven, thus improving quality and reducing product waste.
The speed at which the product is transferred onto the oven line is another important consideration and depends on the type of product being baked. Teeny's pizza bread is larger than its pocket bread and requires a slower conveyor transfer speeds. If a product is transferred onto the baking line at the wrong speed, it will either stick to the tray or be transferred unevenly, thus spoiling it.
This precise speed control is especially important in the production of the deep-dish pizza crusts because, this product must be removed from a circular baking pan. On this baking line, a vacuum pulls the crust from the pan and places it on one conveyor, while the empty pan is taken away by another conveyor.

Spiral Cooling
Conveyor speed of the two-story spiral cooling rack, made by I.J. White Co., is controlled by an Allen-Bradley 1336 AC variable-frequency drive. The rack can hold up to 6,000 pieces of pocket bread at once. Spiral travel times are 20 minutes to cool and 30 minutes to freeze pocket breads.
"Some of our products need to be cooled, and some must be frozen," said Jim Georgioff, engineering manager at Teeny Foods. "If a large thermal mass goes in, a certain amount of heat must be removed. The variable-frequency drive acts as a timer, determining how long each product stays in the cooling rack to achieve the desired product temperature."

Small Size
Teeny Foods wanted to minimize plant-floor clutter and to place the timing devices as close to the lines as possible. Therefore the small size of the controller was a primary reason they were selected. Measuring 2 1/2 in. wide and 5 in. high, as many as 24 controllers fit into a single cabinet, reducing space and wiring requirements.
"There controllers give us an end-rail mounted drive that is tiny," said Tom Hatch, with C-Tech Services, the systems integrator who worked with Teeny Foods on the upgrade. "With circuit protection and an E-stop interlock relay, the package for the total installation is only 4 in. wide by 12 in. high. With most drive packages, that space wouldn't house the basic drive, much less the supporting equipment."
Mr. Georgioff likes the fact that one controller can handle two motors. "We had some motor coordination problems in the past caused by slack in conveyor lines where they make 180° turns," he said.
In the Teeny Foods plant the most difficult line segment to coordinate was the pan conveyor that brings empty pans back to the sheeting line after the product is transferred to the baking line. This conveyor includes two large "S" curves that allow a lot of slack. The controllers coordinate conveyor speed and reduce the amount of slack at the curves.

Better Process Control
To improve process control, Teeny Foods installed DeviceNet communication protocol to coordinate and communicate with plant floor devices. With this setup, the bakery has been able to integrate production on all three of its lines, simplifying and standardizing the process control. From production offices, plant personnel have access to information about all 34 motor controllers at once, including status, speed, current level and heat sink temperature.
"Process control is very important, especially with varying recipe requirements. We like to watch the line for bottlenecks or other problems to reduce product losses," said Mr. Georgioff.
The bakery also discovered that if line problems occur, the DeviceNet communications system makes them easy to diagnose and repair.
Teeny Foods was able to get the new plant up and running quickly because the communication package was easy to install and program, greatly reducing the wiring needed to connect the 34 controllers. Down time was only three days including time spent moving to the new location.

Even More Control
To further improve process control, three PanelView operator interface terminals were installed. All three have the same screens and run the same program so that if one malfunctions, the process can still be controlled and monitored from another.
Because the new controllers are working so well, the company plans to upgrade its packaging line with additional Bulletin SSC controllers to maintain speed control and to integrate this line into the the system.
This assortment of tiny control devices has helped Teeny Foods' new plant to achieve its huge goal to increase production and create more consistent products.