Maximizing Process Productivity By Streamlining Wrapper Infeed In Frozen Pizza Manufacturing

In a four-billion-dollar-a-year packaged pizza market, one would expect to see a sophisticated, broadly-based technological system in place for the processing of this product. In many aspects of the manufacturing cycle this is the case, but the majority of pizza manufacturers are plagued with difficulties in the assembly downstream, specifically with wrapping and the infeed therein, that is causing major headaches for product producers as they are being pushed to their processing limits of production necessitated by accelerated competitive influences.

According to the National Frozen Pizza Institute, 2003 supermarket sales of frozen pizzas in the U.S. was $3.3 billion. This does not include refrigerated and shelf-stable pizza and pizza products, which represent another 7% of packaged pizza sales. With an average sales growth increase of 6% a year, the packaged pizza market is continuing to expand, and frozen pizza represents not only the largest segment of the packaged pizza business, but one of the fastest growing segments of the entire frozen food category. This level of growth attracts manufacturing players who want a piece of the pie, or better stated the pizza, and so the frozen pizza manufacturing market is becoming increasingly saturated with competitive players.

This has taken its toll on the manufacturing process line of many frozen and raw pizza manufacturers. As the demand for production has increased, and the competitive pricing issues have become tighter, the implementation of automated systems needed to facilitate the increased demand has not kept pace with the growth in orders. The result is production snags, slowdowns, and stops of the process line, and not surprisingly an upped defect ratio of pizzas in production. This is showing up mostly downstream in the assembly cycle with wrapping and the infeed system which supplies it.

"Just about all pizza manufacturers have problems with throughput on production." Says Dave Larson, Technical Support with Sig Doboy, Inc., the industry leader in automated process wrappers. "This is an incredibly competitive business. Manufacturers are looking to cut costs anywhere they can, which includes the wrapping and packaging processes."

"When downstream equipment is running inefficiently, not keeping up with the assembly flow, it does not leave the pizzas any place to go." Says Larson. "Resulting in an accelerated pizza traffic jam, slowing of the process line, or the stopping of it altogether. And, an inevitable increase in damaged pizzas."

"There is actually quite a difference between packaging processes from one pizza manufacturer to another." Larson continues. "Some wrap their pizzas frozen, others wrap them raw and then freeze them after they have been bagged. As many as 50% of all frozen pizza manufacturers still hand-feed their pizzas into the wrapper."

That equates to $1.6 billion annually worth of frozen pizzas that are manually fed into a wrapper. This is astounding when you think of it, that the majority of frozen pizzas manufactured in the U.S. are being in-fed into wrappers manually. Not only is this labor intensive, it allows the introduction of human error in pizza-placement registration which brings about product defects and process slowdowns. But even worse, it limits the rate at which pizzas can be wrapped.

Sig Doboy's wrapping machines are capable of handling up to 170 12-inch diameter pizzas per minute, and as many as 300 fun-size ppm. This would certainly be considered industry-standard high-speed production. But factually, this exceeds the infeed process capability of manufacturers, both hand-fed and automated.

So, even if a manufacturer has a high-speed wrapper, its production is modified by the rate of infeed. Hand infeed will never achieve a rate of 170 12-inch pizzas per minute, let alone 300 fun-size.

Many manufacturers are using automated infeeders on their line that do not have the capability of supplying the wrapper with an adequate volume infeed of frozen pizzas, enough to realize any substantial benefit in process speed.

Usually the situation is more so that the automated infeed itself is incapable of effectively managing the product flow. And incapable of properly registering the pizzas in the exact position for the wrapper to execute a successful completed wrap cycle. The result is product damage, jam-ups on the production line, and sometimes shutdown of the assembly all the way back to the start of the line. The money lost in damaged product is nothing compared to the overall loss in man-hours, and loss of revenue because of process downtime.

"Pizzas are a difficult product to wrap", says Todd Eckert, Packaging Program Manager at Shuttleworth, Inc., a manufacturer of custom infeed conveyor systems for the food processing industry, and specifically for frozen pizza applications. "They have a lot of loose ingredients on them that tend to shift around and fall off, and their extended shape requires very careful handling to keep from damaging them."

"When running at high speeds, such as 120 pizzas per minute, most infeed systems cannot maintain proper indexing with the wrapper." Eckert says. "You then get missed flights, or pizza shingling. The problem is that the registration of pizzas gets messed up. The pizzas coming out of the freezer have a relatively uneven bottom, which causes the pizzas to shingle as they travel on conveyor surfaces back-to-back. Any frozen food product that has a low profile such as waffles, pancakes, hamburger patties, cakes and pies have a high capability of shingling."

Shuttleworth has developed a conveyor infeed that solves this problem. Their Servo SmartFeed conveyor accepts random input from the production freezer of pizzas and sequences them with proper spacing between the flight chain fingers to feed the wrapper. Low line pressure throughout the continuous motion accumulation area allows for proper product placement with the correction zones going into the flight pins of the wrapper.

Should the wrapper need to stop or slow, then the conveyor can continue to take production from the line for a period of time instead of stopping. A low-pressure accumulation buffer absorbs irregularities in the production flow, and provides a smooth, even flow on the line.

"Shuttleworth's Servo-SmartFeed operates in four speed-registration zones to manage the pizzas optimally:" Eckert says. "(1) the first zone accepts the pizzas from the freezer, then conveys them at two to three times case feet per minute; (2) the second zone closes the gaps between the pizzas, running the product back to back; (3) the third zone increases the spacing between the pizzas equal to the pitch flight on the wrapper; (4) and the fourth zone positions each individual pizza into the gaps between the flights. The Servo-SmartFeed is in synchronization with the wrapping machine due to encoder feedback from the wrapper. A sensor identifies each product location, and then the conveyor will either accelerate or decelerate the product to place it into position on the flighted infeed of the wrapper to be wrapped."

The length of the Shuttleworth Servo-SmartFeed is determined by product rates and sizes, and can be integrated with many different wrappers and packaging equipment, including Sig Doboy. The machine is custom made for each application, and can handle between 50 and 250 pizzas a minute.

A key component of Shuttleworth's Servo-SmartFeed system is their Slip-Torque technology for creating low back pressure. This utilizes the coefficient of friction between the individually-powered rotating roller shafts and the loose fit rollers, to control the drive force of the product. The size and weight of the product determine the driving force and roller selection. When product stops on the surface of the conveyor, the segmented rollers beneath the product also stop, generating low back-pressure accumulation, minimizing product damage.

"Shuttleworth just recently installed a Servo-SmartFeed for Amy's Kitchen frozen pizza assembly line, in Santa Rosa, California." Eckert explains. "Amy's Kitchen makes pre-packaged vegetarian frozen meals. The company manufactures over 50 million meals a year, and they produce a lot of pizzas. Roasted vegetable pizza, pesto pizza, mushroom and olive pizza, rice crust cheese pizza, and spinach pizza represents some of their frozen pizza line-up. They have a very high volume operation and wanted to double their wrapping capacity."

"We were looking to resolve difficulties that they were experiencing with their original wrapping equipment, which was a high-speed, highly efficient wrapper." Eckert says. "But like most everybody else in the frozen pizza industry, their wrapper was limited by rate of flow from the feeder, and literally limiting their production flow by 50%. They were using a pneumatic plunger-type of device to time-release the products into the wrapper. This was causing pizza shingling, product damage and process-line slowdowns. The integration we did with our Servo-SmartFeed and Sig DoBoy's wrapper solved the difficulties."

By balancing the flow of product going into the wrapper, the volume of throughput was increased and product damage was reduced considerably. Turning this manual operation into a hands-free line eliminated excess labor costs. These are some of the benefits to be gained by using a state-of-the-art infeed system with a wrapper.

Some frozen pizza manufacturers will choose to stay the status quo, and continue to infeed their pizzas by hand, or with antiquated, inefficient and problematic equipment.

As this pizza manufacturing theatre continues to become more aggressively crowded and competitive, those with the most efficient and streamlined process capability will be in a better position to capture market share, and realize more attractive profit margins.

For more information on Shuttleworth and their Servo-SmartFeed and Slip-Torque conveying system technology, please contact Todd Eckert at 260-359-7850; Fax 260-359-7810; 10 Commercial Road, Huntington, IN 46750; email t.eckert@shuttleworth.com; or visit their web site at www.shuttleworth.com.

Contact Sig DoBoy, Inc., and Dave Larson in their Technical Support Department, by calling 715-246-6511; Fax 715-246-6539; 869 South Knowles Avenue, New Richmond, WI 54017; www.sigdoboy.com.

To reach Amy's Kitchen please contact Bert Pires, Manager of Engineering, at 707-578-7188; Fax 707-578-7995; 2227 Capricorn Way, Santa Rosa, CA, 95407; www.amyskitchen.com.