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Package handling: robot palletizing installation for Kelly-Moore Paint

Package handling: robot palletizing installation for Kelly-Moore Paint
Paint cans


pdx1004paint1A new $1.5-million, two-robot palletizing installation at Kelly-Moore Paint Company Inc., San Carlos, CA, saved $1 million in labor last year for an ROI of 66 percent. The robots serve four paint-filling lines; two identical lines run 1-qt and 1-gal plastic cans at 25 cans/min and two other identical lines run 5-gal buckets at 40 buckets/min. “We were manually palletizing all of these products, but this was very labor intensive,” says plant manager Keith Hussinger. “In 2008, we decided to investigate an automatic palletizing operation. We didn't have room for mechanical palletizers, so we settled on using robotic units.”

Kelly-Moore is the largest employee-owned paint company in the U.S., with approximately 163 retail stores, two major manufacturing facilities in San Carlos, CA, and Hurst, TX. that produce nearly 15 million gal of paint per year.

Kelly-Moore looked into several vendors, but settled on FKI Logistics (now Intelligrated Inc.). “They weren't the pdx1004paint6lowest-cost vendor,” says Hussinger, “but we were very impressed by all of the upfront details they offered. They provided at least five design iterations for us to look at, and they were very professional.” Intelligrated provided complete system integration for the project, including product infeed conveyors, a pallet dispensing and handling system and a loaded-pallet take-away system.

Kelly-Moore has two robotic-palletizing cells; one for the pair of gal/qt lines and one for the pair of five-gal lines. The gal/qt cans are loaded onto trays before being conveyed to the palletizer, four gal cans/tray and nine qt cans/tray, while the five-gal buckets are conveyed individually.

Tray packers

As part of the project, Kelly-Moore installed two Model 170 tray packers from A-B-C Packaging Machine Corp. on the two gal/qt lines. The machines are installed in left- and right-hand configurations, so one line attendant can easily refill the tray magazines and glue reservoirs. No lifting is required to load stacks of tray blanks into the low-level extended magazine, and a conveyor moves one stack at a time into the machine, where the stack is raised to the infeed level.

Cans are conveyed from the filler to the side of the packer, where they are accumulated in lanes—two wide for the gal and three wide for the qt. At each loading cycle, a conveyor with chain-mounted flight lugs pushes the top tray blank into the forming section of the machine, where the front flap is folded up. The lugs then push the tray into the loading section, where the back flap is folded up and a load of cans is pushed onto the blank; four gal cans or nine qt cans.

At this point, the front and back flaps are extending out past the tray, and the side flaps are still flat and also extending outward from the tray. A harmonic-motion drive transfers the tray through the hot-melt glue applicator from Nordson Corp., which sprays the glue onto the end flap extension. In the next machine zone, the side and end flapspdx1004paint12 are folded around the product load by steel folding arms that securely square and seal each tray, for tight-pack trays that palletize well. The trays are then conveyed to the palletizer.

The packers are controlled by Allen-Bradley PLCs from Rockwell Automation. Safeguards switch the packer to standby mode if the tray or product supply is interrupted and resume normal operation when the supply returns.

Unique end effectors

The paint cans/buckets from each pair of lines enter the palletizing cell dedicated to those size containers on two parallel conveyors, and the containers from each conveyor are palletized on a pallet dedicated to that conveyor. Thus each filling line can run a different product. The robot swings from one conveyor to the other to pick up the cans and place them on their respective pallets. For this project, Intelligrated selected Model EPL 160 robots from Motoman Inc. Designed specifically for palletizing, these four-axis units feature internally routed air and I/O signal lines between the base of the robot and the end-of-arm tool to virtually eliminate cable and hose wear. This improves flexibility and minimizes downtime.

The end tools for the two robots are both vacuum-activated, but otherwise are very different. The gal/qt unit, which picks up three cases at a time, utilizes an end tool from Swedish supplier Tepro Machine & Pac System AB. This tool, which uses a blower to generate vacuum, is a large foam-covered plate that features a series of valves in the plenum that shut off if they are not covered by the cans being picked up. Thus, the vacuum is applied only to the area where cans are present. This combination of a strong vacuum generator and a directed vacuum application provides a very strong lifting capability that can handle the heavy load of cans. Another feature of this tool is a vacuum arm that swings in against the tray and holds it in place when the robot is lifting the load. This is required because the top vacuum only holds the cans, so the tray would fall off if this arm was not present.

The bucket robot, which picks up three buckets at a time, has a more-standard end effector from Intelligrated that uses a compressed-air venturi to produce the vacuum. This effector required its own design because the five-gal buckets have a small port in the top through which tinting color can be added to the contents.

To ensure that this port would not be opened inadvertently during palletizing, it was necessary to make sure that the vacuum would not be applied to the port. Intelligrated accomplished this by designing a 2-in. wide ring with raised lips on the end effector that would contact the lid of the bucket and shield the port from the vacuum.

The palletizing installation includes a pallet-dispensing system with a magazine that holds 20 to 24 pallets. When the controller calls for a pallet, the entire stack is lifted. Fingers come in below the second pallet from the bottom, after which the bottom pallet is lowered onto the conveyor and conveyed to the robotic cell that needs it.

When a pallet is completely loaded, it is transfered onto a cross conveyor that transports it to a stretch wrapper.


PC-based control

pdx1004paint_chartThe entire palletizing operation is controlled by a Motoman NX100 PC-based pendant controller that features a Windows® CE programming pendant and fast processing, easy-to-use INFORM III programming language. Advanced motion- control provides high-performance path accuracy and vibration control, while dual-channel safety features include enhanced E-Stop functionality, integrated speed monitoring and manual brake release for the robot. The NX100 eliminates the need for a separate PLC, providing significant cost savings and decreasing system complexity.

The NX100 teach pendant features a unique cross-shaped navigation cursor that reduces teaching time by 30 percent. Other features include a full color touch display, compact flash slot for easy backups and an optional online troubleshooting guide for expert system maintenance. Most operator controls are located on the pendant, allowing the NX100 control cabinet to be mounted remotely.

“Intelligrated has been great,” says Hussinger. “They assisted with the installation and startup and also provided onsite training for our operators. We run the systems constantly, and the uptime from maintenance blew away my expectations. They have local representatives who are always available, and their service has been superb. We had a mishap that damaged some equipment, and a service man flew out here from St. Louis on a Friday night and was in the plant Saturday morning.”

More information is available:
Intelligrated Inc., 513/701-7300.
A-B-C Packaging Machine Corp., 727/937-5144., 502/267-4200.
Motoman Inc., 937/847-3200.
Nordson Corp., 770/497-3700.
Rockwell Automation, 414/382-2000.
Tepro Machine & Pac System AB, +46 560-27270.

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