Automating Pan Handling
Feb. 1, 2012
by Shane Whitaker
For wholesale bakeries wanting to minimize safety risks to employees, pan handling represents an area to reduce several worker safety hazards. Whether it’s working around hot metal objects that can cause burns or lifting and moving pans repeatedly that risks repetitive motion injuries, manual pan handling can be a precarious task.
Many bakeries have increased their SKUs, thus making the job more difficult to move pans on and off lines or to store and retrieve them without assistance of automated equipment. “I think a bakery is in need of an automatic pan storage/retrieval system when there are multiple pan types involved and multiple changeovers required,” said Frank Achterberg, president, Capway Systems. York, PA.
As bakeries increase line speeds with larger pans, they risk greater chances for workers to sustain back injuries, according to Billy Rinks, national sales account manager, Stewart Systems, Plano, TX.
Larger plants operating around the clock may gain the most from automated pan handling systems. However, Charles Gales, manager, automation sales, Weldon Solutions, York, PA, said, “even smaller bakeries with only occasional pan changeovers can benefit from automation by keeping their employees focused on higher value-added tasks than moving 20 to 30 pans per minute.”
Most automated pan systems have a return on investment of three years or less, added Roland Lomerson, vice-president of automation, AMF Bakery Systems, Richmond, VA.
Minimizing pan damage
The greatest benefits from automated pan handling systems include less worker fatigue, faster rates and less damage to pans and their glazing, according to Mr. Rinks. “These three factors are the basis for determining return on investment,” he said. “It differs from bakery to bakery, but a good rule of thumb would be two to five years based on how much automation is done.”
Stewart manufactures pan stackers/unstackers as well as conveyors to move pans from point A to point B. Its stackers/unstackers can include features such as fully recipe-driven machines to light curtains for personnel safety. Bakeries can setup the stackers/unstackers to either interface with manual pan trucks or automatic storage and retrieval systems. Additionally, Mr. Rinks noted Stewart’s machines include inverter-controlled motors for soft starts and stops to gently handle the pans.
The Capway RoboCap features a gantry-style robot that unstacks, stacks, stores and retrieves pans all within the same unit. “The advantage is that only one system is required for all the operations required,” Mr. Achterberg said. “The large gripper allows multiple pans to be picked up at one time, therefore reducing the cycles the robot has to perform.”
By stacking and unstacking the pans vertically, Capway’s system handles pans gently and does not touch or damage the coatings in the pans, thereby extending pan and pan coating life.
AMF currently offers two types of automated stackers/unstackers, and third is under development. The company’s mechanical system uses a flighted AC-driven vertical elevator, and an electromagnetic tool picks each pan. This system typically is integrated with a hand truck storage system, according to Mr. Lomerson.
AMF’s other technology features an articulating arm robot to pick and place multiple pans at a one time. Soft touch tooling in which magnetic contact points are cushioned offers gentle handling. “Each of the magnetic contact points are programmable using a pneumatic release technology,” he said, noting that it can be integrated with automatic storage and retrieval systems or pan trucks.
Scheduled for release this fall is AMF’s Servo Swing Arm system that uses the same soft touch tooling as the robot technology but at a fraction of the size. “The servo movements provide for precision picking and placement of the groups of pans and, like the robot system, eliminates the potential for any pan damage,” Mr. Lomerson noted. “It is extremely quiet and can adapt to a variety of configurations and elevations.”
Stacking pans upside down provides a mechanical advantage because the lip of the pans can support heavier weights than the pan pockets can and contamination is less of a concern, Mr. Rinks said. Accordingly, many bakeries push to handle the pans upside down. While this method is being implemented in some newer bakeries, the challenge is how to do this in existing bakeries. Stewart’s stackers/unstackers can handle pans upside down; however, this change could require slight modifications to the machines.
In addition to reducing damage to pans, such methods create taller stacks, which will decrease the required floor space for storage.
Smaller and more efficient
Space is at a premium more than ever in bakeries. Because RoboCap stores pans internally, it does not need pan trucks. “This allows higher stacks because they do not have to be moved after stacking, so less floor space is required,” Mr. Achterberg said.
RoboCap’s greatest benefit is that it automatically meters the line, he noted. “It adds and removes pans based on the line requirements,” Mr. Achterberg said. “It allows easy changeovers without the need to move heavy pan trucks around and the possibility they might fall over and hurt someone.”
Bakeries continue to look for greater production from a single line, according to Ken Mentch, vice-president of sales and marketing, Workhorse Automation, Oxford, PA. “In an effort to meet these new production speeds, pan rates, pan sizes and pan weights increase with the demand, which in turn prompts bakers to look for better pan handling solutions,” he said. “Our latest system handles 27-lb pans. This is a pan that cannot be manually stacked or unstacked at the required production speeds of 30 pans per minute.”
Workhorse introduced a Dual Gantry stacker/unstacker system, which provides reliable, gentle, accurate high-speed pan handling for all bakery pan and lid needs, according to Mr. Mentch. “The Gantry stacker/unstacker integrated with our Multi-Level storage and retrieval system and pan inverter cleaner provides the customer a complete on-demand system, which is seamlessly integrated together by a user-friendly, intuitive Allen-Bradley control scheme,” he said.
Weldon’s E300 pan shuttle incorporates the latest electronics into its new design, according to Mr. Gales. “Positioning lasers are now incorporated into all axes of motion, and the E300 control system has the ability to adjust speed automatically to satisfy real-time bakery requirements,” he said.
In addition, Mr. Gales claimed that the pan shuttle line handles the wide range of pans used in the industry and has the ability to service more than one production line at one time.
Maintaining these assets
Because bakeries have ever more equipment to maintain, one of the biggest challenges becomes avoiding unplanned downtime. To this end, Weldon focused its automated pan handling equipment design and development efforts on anticipating potential fault conditions and expediting corrective actions.
“Should a component need to be replaced, getting the system back in operation quickly is of the utmost importance,” Mr. Gales said. “Equipment design has evolved to the point where failure-prone devices have been eliminated or located in an easy-to-replace position. Examples on the E300 pan shuttle include a floor-level electrification system, externally mounted electric cable reel with quick-connect plugs, wireless communication to the transfer vehicle, and lasers to improve speed and positional accuracy.”
The company’s man-machine interface screens employ icons that allow the operator to intuitively address production issues. “Maintenance screens with 3D drawings that clearly show equipment, along with sensor locations and status, are provided to simplify troubleshooting,” he added.
Mr. Rinks said that bakeries must maintain new equipment from the early stages onward. “The new machinery will run well and will seem like it does not need any maintenance, but it should be on a preventive maintenance schedule to prevent future problems along with having the proper spare parts on hand,” he added.
Mr. Mentch noted that one of the remaining challenges with pan handling equipment is operator and maintenance training. “Bakeries today face a difficult scenario with the frequent turnover of operators and maintenance personnel, and keeping the new employees properly trained about the pan handling equipment can be difficult,” he said. But at least learning how to operate these systems won’t be the backbreaking labor required when manually moving pans on and off the lines.