Stability and strength
March 1, 2015
by Charlotte Atchley
Pans are the basic must-have in a bakery. They’re like the flour of equipment. Pans are such a ubiquitous part of the production line that sometimes they seem to get lost in the noise of everything that needs automation and attention. However, ignore them in a bakery, and bakers run the risks of incurring a lot of unnecessary costs replacing damaged pans prematurely.
“As pans and lids age, or get seasoned, through thousands of passes in a bakery line circuit, they can get warped, bent or otherwise drift out of original dimensional specifications,” said Jerry Barnes, vice-president of business development and marketing, Baker Thermal Solutions and Stewart Systems, subsidiaries of the Middleby Corp., Elgin, IL. “Glazing wears off, and oils bake on the surface.” And that’s just typical wear and tear pans incur from normal use.
Two types of damage endanger pans. The structure of the pan can be bent or bowed from running through equipment and conveyors. The second is damage to the glaze or coating on the surface that provides non-stick properties. To protect their pans and make them last longer, bakers have turned to automated pan handling and innovative pan design. Robots provide gentler handling and smoother transitions than manual methods. New stacking strategies built into pan design now improve the stability of pans for storage, and the materials and coatings used to build pans are getting stronger and more scratch-resistant.
“Bakers realize that pans are an investment, and the better you take care of your pans, the better your return on investment,” said Steve Schwartz, president, Bakeware Coating Systems, Camden, NJ, and Anaheim, CA.
How pans move through the plant and are handled throughout often put them in the danger zone. These days with production moving faster and faster, human operators can’t always keep up with older systems without being rough on the pans. “Pan handling systems of today are far easier on the pan than the old stackers from 15 to 20 years ago,” Mr. Schwartz said. “People realize you’re not just dropping them anymore.”
That’s in part thanks to robotics that mimic the gentle touch of human hands but can move much faster. “We grip that pan with fingers that emulate a person’s, but the robot clips onto the pan and sets it down in the stack,” explained Bob Harringon, vice-president, sales, Capway Systems, Inc., York, PA. “The movement is a smooth transition. You don’t have to worry about the system keeping up like with manual systems where the pans can fall off the conveyor if the operator can’t keep up.”
Today’s robots can not only keep up with production but also move pans with smoother, gentler motions, ensuring minimal, if any, damage. Much of this has to do with the capability to handle multiple pans at once.
“We could be handling four, six, eight or 10 pans at a time for each machine movement, so it greatly reduces the amount of motion of the pan for stacking and unstacking,” said Kenneth Mentch, sales manager, Workhorse Automation, Oxford, PA, describing the company’s robotic gantry pan and lid stacker/unstacker.
The ability to handle multiple pans at one time enables the stacker/unstacker to match the higher production speeds while still maintaining gentle movements, saving the pan’s integrity. “Today’s faster line speeds are pushing the limits of the conventional design’s ability to handle pans properly,” said John Keane, engineering product Manager, AMF Bakery Systems, Richmond VA. “Handling multiple pans at once has an appeal in minimizing the impact the automated systems have on the pans.” The company’s PALSUS unit was designed for that very purpose. The result is quieter and more gentle handling.
To accommodate throughput while also providing softer movements, Stewart Systems implemented servo technology. Servo motion profiling replaces the vertical air cylinder of the stacker/unstacker, according to Mr. Barnes. This allows closed-loop high speed positioning at faster rates. “Moreover, the servo-electric cylinder can encompass S-curve motion profiling for fast moves with gentle starts and stops,” he said.
Today’s production rates can pose their own threat to pans. As production lines speed up, if and when pans collide and jam, the damage will be much worse at high speeds just as it would be in a high-speed car accident. To slow things down without losing throughput, Frank Achterburg, president, CBF Bakery Systems, York, PA, suggested running the pan the wide way, with the long edge forward. “This reduces the line speed, but not the production rate, and then you can double up on the pans,” he said. CBF Systems also tries to eliminate areas where pans can accumulate. With fewer places for traffic jams, pans are less likely to collide, and if they do, reduced speeds ensure it won’t be disastrous for the pans’ structural integrity.
Storage is another point in the facility where pans run the risk of being damaged. “Obviously, how the pans nest into each other is critical in terms of the wear and tear on the pan itself, specifically making sure weight is distributed evenly along the borders between pans,” Mr. Schwartz explained.
Pans are designed to nest within one another for easy stacking and storage. “Often, the majority of pan damage and stress occurs in the pan stacking and storage operations since the bottom pan of a stack needs to support a significant weight,” said Jason Tingley, vice-president, American Pan, a Bundy Baking Solution, Urbana, OH. However, the way pans are stacked conventionally places the weight of the stack on the cups of the bottom pan.
Workhorse Automation’s system turns pans upside down before storing. Instead of supporting the stack’s weight on the cups, this approach puts all of the weight on the reinforcing band around the pan’s edge. “That provides a lot more support to the pans and less damage to the bottom of the cups,” Mr. Mentch said.
Once stacked, it’s also important for those stacks of pans to be stable to prevent any toppling. Workhorse Automation’s robots create a more stable load by stacking the pans in layers instead of traditional pillars. A conventional stacker/unstacker will stack pans by pillars, and then a conveyor groups those pillars together to create a full load of pans ready for storage.
“With the robot, we’re building the whole load by layers, putting all five pans in the first layer down, then all five pans of the second layer, and then the third and fourth,” Mr. Mentch said. “We’re building a much more stable load by building it by layer vs. pillar.” This way, in case of a partial load, there isn’t a singular stray pillar of pans being moved around. By building a load by layers, a partial load is lower to the ground, minimizing the opportunity for toppling.
Designed for strength
Automation can move pans smoothly, quietly and gently throughout a plant and store them in safest way possible, but even the design of the pan itself can increase its resistance to the inevitable wear and tear of daily use in a bakery.
Pans typically come to the baker with a non-stick coating, and after a set number of bake cycles, that coating must be replaced to ensure optimum release effectiveness. Lengthening the time between re-coatings saves bakers time and money, another benefit of automatic handling.
Metal-on-metal contact can scratch the surface of the coatings, hindering its non-stick abilities. “There are coatings that resist metal-on-metal contact, and that’s one of the places where we’re investing a lot of R&D,” Mr. Schwartz said. Bakeware Coatings’ 230 series of pan coatings was developed to stand up to pan abrasion due to mechanical wear.
Beyond the coating, pans are being made to endure the amount of stress placed on them by automation. “Understanding and developing the correct pan design is very important because there are many options that can affect pan life, product characteristics and the overall throughput of the bakery,” Mr. Tingley said. According to American Pan, high-strength steels, reinforcing ribs and gussets, and inverted and moated bun pan designs can all add strength and durability to a pan. The company’s ePan pans are constructed of high tensile strength aluminized steel to create a stronger pan that is 35% lighter and cools up to 17% faster than traditional pans.
“The pan designer should thoroughly understand the unique bakery environment and storage system to offer the best and most durable pan design,” Mr. Tingley said.
Other adjustments in size and mould arrangements on bun pan or size and strap configuration of bread pans can also decrease oven gaps between pans, increase throughput and reduce line speed.
At the end of the day, the pan is the vehicle that carries the product through the bakery from start to finish. To ensure it gets from point A to point B in the best shape possible, the pan itself has to be in the best shape possible. With proper automated handling and pan design, bakers can achieve that while maintaining the throughput rates their customers demand.