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At its mill in St. Jérôme, Qué., Rolland Inc. has added automated roll wrapping and handling as a way to reduce paper loss and labor costs. A previous project had moved sheeting operations to an offsite facility, opening the finishing floor to a more efficient layout. However, roll wrapping was still done manually at a level below the production floor, and all rolls had to be taken by clamp truck to a lowerator for final, manual wrapping.
In 1998, a Rolland team was assembled to reorganize the mill layout and to make equipment changes as a way to eliminate two-floor operations and the lowerator as a production device. The team began looking for ways to automate roll wrapping and handling that would improve efficiency and reduce inventory levels, labor content, and human error in wrapping and labeling of finished paper. Also, automated roll delivery would reduce manual handling costs and associated product damage.
Rolland's AGV places a paper roll onto the infeed position of the roll wrapping line.
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In short, the Rolland team wanted to replace manual, multi-level operations with an automated system's approach to handling and wrapping. Their project was undertaken at a mill where numerous short runs of a wide variety of paper widths (8 in. to 80 in.) and diameters (20 in. to 60 in.) made automation seem impractical. However, careful engineering analysis and the appropriate equipment, including an automatic guided vehicle system (AGVS) and newly configured wrapping line, proved to make the project one that reduced product damage, paper machine overruns, labor cost-per-ton, storage requirements, and maintenance costs, as well as providing other intangible benefits.
INEFFICIENT WRAPPING OPERATIONS. Rolland, which is now a member of the Cascades Group, was founded in 1882 and is a producer of specialty uncoated fine papers and high-end deinked pulp. Before the roll wrapping and handling project was undertaken, Rolland employed five clamp truck operators on the first shift. The work was accomplished with three men on second shift and two on third shift when production was reduced and rolls were only stored and not wrapped.
On first shift, three operators worked on the main floor trucking rolls to the lowerator for wrapping and then to the offsite sheeting facility or to the lower floor storage and shipping dock. On the lower floor, there were two clamp truck operators-one removing the product from the lowerator with infeed responsibility to the manual wrapping operations and another clamp truck driver moving rolls into and out of wrapping roll storage.
All the repeated clamping of the finished unwrapped rolls created a condition where a high percentage of production ended in waste. Adding to the waste was eccentricity caused by storing the rolls on their bilge for too many hours during the night. Between 1/8 in. and 1/2 in. of each roll was removed prior to wrapping because of damage.
Another problem the mill hoped to address with automation was control of finished product. When an order was in the process of being filled, the paper machine operators routinely made more product than was required by the customer because they didn't have good information on how much finished paper had been wrapped. Too much time, manual data exchange, and damage risks prohibited efficient production runs.
At the wrapping line, rolls are individually deposited and centered on a roll kicking station by the AGV.
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A NEW SYSTEM. With the new roll wrapping and handling project, it was hoped that production runs could be shortened. The idea was that, with automation, the weight of first quality, wrapped product for a particular order could be transmitted in real time to the machine operators. This would then let them know how many more tons to make and, therefore, when to end the papermaking process.
An AGVS was included in the project, which encompassed moving the wrapping line to the first floor, utilizing the space opened by the previous project, and placing the roll wrapping line adjacent to two of the four paper machines. It also involved bringing in newly configured automated roll wrapping equipment.
The AGVS includes an automatic guided vehicle (AGV), along with a host computer to queue orders, manage traffic, and receive remote inputs from programmable logic controllers (PLCs). The AGVS was incorporated to reduce manpower for the trucking of the rolls from two paper machines to the wrap line. The AGV had the additional benefit of carrying the rolls on roll-shaped forks to eliminate damage previously caused by the clamping of the rolls.
Further, the AGV would be used as a just-in-time delivery tool so that when rolls were produced and presented to the AGV system, it would immediately deliver the product to the wrap line. This would avoid costs associated with repeated product handling by clamp trucks (and the ensuing damage), labor for operation of the clamp truck, maintenance of trucks, and floor space for storage of inventory. It would also result in better mill ergonomics by eliminating the danger associated with clamp truck operations.
It was determined that the best use of the AGV would be to have it carry "sets" of parent rolls grouped together in their largest configuration. This would reduce the number of AGV moves per hour.
Mentor AGVS of Cleveland, Ohio, the North American distributor of vehicles produced by Rocla Robotruck of Jarvenpaa, Finland, supplied the AGVS. By working closely with the Mentor group, Rolland was able to coordinate the supply of a single, laser-guided vehicle to transport roll sets to the newly-configured roll wrapping line.
The vehicle, which is battery powered and based on the required throughput, is able to automatically recharge its onboard batteries when not delivering rolls. This opportunity for charging takes place at a home position that is located near the two paper machine pickup stations that are remotely located.
The vehicle has an industrial laser mounted on the top of the vehicle mast that rotates six times each second and is able to navigate using triangulation principles-taking reflections from stationary targets located at the perimeter of the travel path. This laser guidance required that nothing be installed on Rolland's mill floor. Targets were simple reflective strips mounted on available stationary surfaces to provide positioning accuracies of +/- 1/2 in.
At any time before, during, or after commissioning, Rolland was able to simply change the AGV's path by modifying values in the software tables in the vehicle's central, onboard processor. Changes in this system have been made by sending email changes to the mill maintenance personnel to download.
Since the AGV is driverless, safety was a paramount concern. Onboard safety devices include eye-level emergency stop push buttons that let operators stop the vehicle if necessary, non-contact sensors to slow the vehicle when objects are detected within the programmed distance, and mechanical bumpers that, if tripped, activate the emergency stop circuit and require a manual reset to make sure obstacles are understood and removed from the path. Also, if the vehicle strays from the pre-determined path by more than two inches, the central, onboard processor will stop the vehicle and signal an error.
In addition, warning horns and flashing lights signal operators when the vehicle is nearby, and fail-safe brakes are held off electrically and spring on in the event of a power failure.
MORE EFFICIENT OPERATIONS. The AGV communicates via spread spectrum radio with a Windows NT-based stationary operator control station located near the roll wrapping line. The stationary controller takes inputs from bar code information through a PLC link as each roll comes from the paper machines. The PLC inputs also indicate how many rolls are to be grouped together for transport.
All rolls are picked up and deposited from floor-level, so there are no conveyors or other equipment mounted above the mill floor. At the new wrapping line, rolls are individually deposited and centered on a roll kicking station. This four-directional centering permits close spacing of the rolls on the wrap line and, thus, higher wrap line throughputs.
Because the rolls vary in diameter from 36 in. to 60 in., the AGV had to be equipped with automatic, adjustable roll forks. These contoured forks are powered by onboard hydraulics and controlled with sensors that stop the forks from traversing inward when the roll is in close proximity. Product damage is avoided, because, when in proximity, the mast lifts the roll gently off the floor for transport.
After the project was completed, the mill ended up with only two operators working with roll wrapping and handling on the first shift, and sometimes less on second and third. No industrial truck operators currently handle rolls between any of the four paper machines to the roll wrapping line, although one person still trucks rolls for the offsite converting facility.
Rolland's project was completed in approximately seven months. Results included the initial annual savings in labor and reject or waste paper. For the entire project, the return on investment came between two and three years, and, for the AGV subsystem, less than two years. In addition, less paper machine overruns and reduced inventory storage requirements were realized. The elimination of the noise and danger from lift trucks was an intangible, as were the improved logistics of locating all finishing to a single floor. Also, the AGV has required less maintenance than the trucks and has been less damaging to the mill floor due to better weight distribution from bigger tires over a larger footprint.
Michael Urban is vice president of Mentor AGVS, Cleveland, Ohio. Jocelyn Riopel is project engineer of Sandwell Engineering, Montréal, Qué.
ACKNOWLEDGEMENTS. The authors would like to acknowledge Michel Charbonnea, general manager; Robert Birch, director of purchasing;  and Real Bordeleau, manager of engineering at Rolland Inc., St. Jérôme, Qué.
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