Pickles palletized robotically

Aliment Putter's Food, Inc., Sainte-Sophie, Quebec, a well-known eastern Canadian producer of a wide variety of pickled-vegetable products, found itself in a bit of a production pickle. Its manual end-of-line palletizing operation was limiting its processing capacity, particularly during its peak season between July and mid-November, when Putter's typically runs up to 12,000 cases/day, while operating one 10-hr-plus shift, five or six days a week. “Even with three people palletizing, we couldn't take product away as fast as we could produce it,” says Putter's owner and president, Alvin Goodz. “Cases weigh up to twenty pounds each. Stacking them onto pallets for shipment is a backbreaking, physically demanding job that was just killing our employees. People were quitting left and right. Nobody wants to work that hard. It was time we bought a robot, so we did, and we've been very happy with it.”

In September 2005, Putter's implemented a four-axis Model SP100X palletizing robot from Motoman, Inc. (www.motoman.com) into its operation. “People always worry that robots will eliminate jobs, but this robot has actually helped create more jobs in the plant, and we've been able to hire more people as a result.” Goodz says. “The palletizing robot works all day long and doesn't break a sweat. It never misses a day, gets tired or takes coffee breaks. It also never asks for a pay increase. It's wonderful.

“Our employees are happier. They're not strained or stressed, now that we have the robot. It creates a better, happier atmosphere. We can now take product away as fast as we can produce it. The palletizing robot does a physically demanding job that people don't want to do, and, as a result, we've actually been able to hire more people for the processing line and increase production, because the robot can handle it. Consequently, our unit cost has gone down.”

Established in 1948 with only two or three employees, Putter's is a family-owned business that now employs 50 to 60 people during peak season, when it produces primarily pasteurized (cooked) products that do not require refrigeration, such as dill, gherkin and bread-and-butter pickles; hot banana peppers; sweet pimentos; and sauerkraut.

Putter's also does a lot of transformation work during the off-peak season. The transformation process involves removing products from barrels, where they have been soaking or fermenting in brine solution, and packing them into jars of various sizes. Off-peak, the company employs about 30 people and produces nearly the same volume per shift, but it processes more of these unpasteurized (uncooked) products that do require refrigeration, such as original (kosher-deli style) dill pickles, dill tomatoes, pickle relish and deluxe mix.

All products produced by Putter's are approved kosher. They also are Canadian Food Inspection Agency (CFIA)-certified, as well as U.S. Food and Drug Administration (FDA)-approved. In addition, Putter's is currently undertaking the stringent process of obtaining Hazard Analysis and Critical Control Point (HACCP) certification.

The company's products are distributed under the Putter's Food label to retailers and wholesalers in Canada and the U.S. and are also sold under eight to 10 private labels. Sales are split about 50/50 between Canada and the U.S., Goodz says.

Putter's packages the company's 18 different products into 500- and 750-mL, 16-oz and 1-, 2- and 4-L jars. It uses seven different sizes of corrugated cases, with dimensions ranging from 6.75 to 12.625 in. wide by 12.25 to 17 in. long by 5.75 to10 in. high. All of the cases come with dividers, some of which are loose, while others are preglued into position. Jars are machine-labeled and packed into cases by hand, after which the cases are sealed with tape prior to being palletized.

Cases of product enter the robot cell via a single-lane, powered infeed conveyor. Sensors on the conveyor indicate that the cases are in the proper location and are ready for robotic pickup. The four-axis Motoman SP100X robot has a 220-lb payload and a 360-deg work envelope with a 129.6-in. reach and a repeatability of ±0.02 in.

The XRC 2001 robot controller provides overall control of the robotic palletizing cell, but Motoman integrated a low-cost Zen controller from Omron Electronics, Inc. (www.omron.com/oei) to run the conveyor photoeyes and gate system as well as the operator pushbutton stations. Changeover between product types is easy. The operator simply selects a different program using the robot's teach pendant, and the system is ready to run the next batch.

The palletizing robot is equipped with a custom-designed, multifunction gripper that uses a single-zone vacuum device along with a pneumatically actuated mechanical side plate to securely hold and transfer the cases, regardless of their size or weight. “With the setup we have that uses both vacuum and side-plate grippers, the robot will never drop a case,” Goodz says. “Someone would have to turn off the air hose. It wouldn't be the robot's fault.”

The robot gripper picks up the smaller, lighter cases, which weigh eight to 38 lb each and palletizes them at a line rate of 10/min. The robot palletizes the tall, narrow, 20-lb cases, which contain two 4-L or 1-gal jars each, two at a time. Even though the robot carries a 40-lb payload each pick cycle, the palletizing rate for these heavier cases is twice as fast (20/min). The line rate is faster with the 4-L jars because it takes less time to fill and label the larger containers than it does to fill and label multiple smaller jars.

The robot stacks the cases onto wooden pallets located in one of two palletizing stations called Side A and Side B. Each pallet layer for the various products contains 10 to 21 cases, and the stacking patterns vary. The robot does not palletize mixed loads of product at this time. Products run in batches, and only one type of product is packed on a pallet. Full pallets are removed by forklift and are replaced with empty pallets, while the robot continues to palletize cases in the other station. Full pallets are shrink-wrapped in another area of the plant prior to shipment.

Putter's provided the workcell guarding for the cell. The guarding includes safety fencing and light curtains to protect personnel from entering the robot's work envelope during operation. Yaskawa Motoman Canada (www.motoman.com) provided the robot solution and systems integration and also did the initial programming.

“Programming the cell presented a little bit of a challenge due to the height variances in the wood pallets and the fact that the floor in the robot cell is not level. There is about a one-inch slope from one side of the pallet stations to the other,” says Bruce Clifford,the YMC senior application technician who did the initial programming. “If these pallet variations or facility issues had caused any real problems, we could have added a sensor to the gripper to check the height of the pallet prior to stacking the first layer, but it was not necessary.”

Says Goodz, “My son, Howard Goodz, the company's production supervisor, handles any programming touch-ups we need. He studied and learned the basics, and he's gotten pretty good at it. We didn't take advantage of Motoman's formal training classes, but they are probably a good idea. In fact, I think everybody should take a programming course before they buy a robot to see if they can handle it.

“This was our first robot, and it's been a good experience. We're still learning what the possibilities are with the robot. What we have is a relatively low-cost, basic system, but it has the flexibility to allow us to add a second infeed conveyor as well as automatic pallet feed and product feed, so it is a solution that can grow as the company grows. The Motoman robot has been very reliable. It just keeps working. At the beginning, when we were first getting up and running, we called for a little technical help. Once we got it up and going, we've never had a problem with the robot. The actual financial payback will take a couple of years or so, but in terms of peace of mind, the robot has already paid for itself.

“We're currently thinking about getting another Motoman robot to put the jars into the cases. We're especially interested in automating packing of the four-liter [1-gallon] jars that weigh ten pounds each. Case packing these large jars by hand is exhausting, and it puts a lot of strain on the operators' arms and wrists, especially at the line speed that we run. This packing application will be a good one for a robot, especially since it will be packing the two large jars into cases that already have preglued dividers.”