A leaner, faster production process with zero defects and Just In Time (JIT) inventory management is an elusive manufacturing goal for most manufacturers.
Water Heater Innovations is one step closer to achieving that goal in the production of its all-plastic, electric water heaters, thanks to a customized foam roll cradle that speeds the production process, delivers labor and storage savings, and reduces product inventory needs.
Water Heater Innovations, an affiliate of Rheem Manufacturing Company, has turned to Rollguard, a company best known for its protective packaging solutions for paper and film rolls, to solve a production challenge.
Located in Eagan, Minnesota, Water Heater Innovations manufactures Rheem Marathon® all-plastic water heaters, which are popular with electric utilities. Until recently, the company was experiencing a small glitch in its production process that was costing time, space and ultimately money.
“As part of our manufacturing process, we do what is called filament winding, where glass fiber impregnated with a resin is wound around the water heater bladder, or liner,” explained Glen Bayer, senior manufacturing engineer, Water Heater Innovations. “The tanks are then put on hangers and hung in a curing oven in order to create the strength needed to withstand the water pressure.”
“Previously, when we took the tanks out of the oven, we would stack them on top of each other in preparation for the next step in the process, which is inserting them in the plastic outer jackets and filling the space between jacket and tanks with insulating foam,” said Bayer. “If the tanks weren’t completely cured when we stacked them, contact with each other could bind them together. When we tried to separate them, the tanks could be damaged or, at the very least, have a small indentation. Neither outcome satisfied Rheem quality standards.”
The company looked at several solutions, including lengthening the curing time and storing the tanks separately, but neither proved feasible. So Bayer searched the Internet for new ideas and discovered Rollguard, a leader in recycled-fiber, foam and plastic roll cradle protection for cylindrical and rolled objects.
Noticing the shape similarities between the water heater tanks and some of the cylindrical products that Rollguard cradles are often used to protect during shipping and storage, he contacted the company. Rollguard, part of Great Northern Corporation and based in Appleton, Wisconsin, was eager to help Bayer solve his challenge.
“Rollguard was great to work with,” said Bayer. “Their team, led by Account Manager Gary Lawell, came to the plant, analyzed our needs and produced several sample cradles that we could place our cured tanks in so they wouldn’t come in contact with one another.
“The one that worked the best was an expanded polyethylene cradle, which they customized for us,” added Bayer. “These yokes (we call them yokes because they look like oxen yokes) are perfect for our needs. The tanks never touch each other, and they don’t stick to the yokes.”
Lawell said he felt confident from the start that Rollguard’s variety of cradles contained the answer to Bayer’s needs. The characteristics of the long-life reusable polyethylene cradles were the logical solution.
“The long-life reusable cradle’s durable construction gives a superior memory capability that allows it to retain its shape longer and be used over and over again, while delivering protective functions that are superior to EPS or other foam cradles on the market,” agreed Rollguard General Manager Rob Swannell. “That makes this cradle ideal for operations that would benefit from highly durable, long-lasting cradles for their internal storage and handling of materials.”
The cradles can be easily custom-fabricated with no upfront tooling costs and in any quantity to accommodate nearly any size, shape or storage configuration, added Lawell. “In Glen’s case, durability, strength and customization were key.”
Bayer estimates that the Rollguard cradles save about four labor-hours per day that Water Heater Innovations employees previously spent separating the water tanks that had become stuck together and moving the tanks around.
And, because the cradles are designed to fit on standard-sized pallets, they are freeing up additional space in the factory. With each tank securely nestled in a cradle, they can be safely stacked in a way that uses less floor space than before.
“We used to have to stack them in a log-pile formation on oversized pallets that had to be custom-built,” said Bayer. “The pallets were about twice as long as standard pallets and they had a really heavy roll bar built around them to contain the tanks. The pallets were really bulky and difficult to handle, so we were limited in what we could do with them.
“We now generally put two layers of tanks on a standard-sized pallet, but we can go as high as three,” added Bayer. “Single-sided cradles are screwed to the pallet and then we use double-sided cradles on top of the tanks.”
Bayer said he believes the cradles will also help improve cash flow and inventory control by making his production process leaner.
“Finished goods are our most expensive inventory,” he explained. “Because our customers have so many individualized needs such as labeling and wattages, it’s difficult for us to carry every finished product in stock for ready shipment. It takes about five days from the time we blow-mold a liner to when we have a finished water heater boxed and ready to ship.”
Bayer said that by using the Rollguard cradles, he is now able to store more completed tanks that can then be turned into finished goods to order in less than a day.
“We are projecting more than a 50-percent reduction in our finished goods inventory,” he said. “We expect to see a significant improvement in customer service and delivery time.”
Now, nearly a year since first implementing the new cradles, Water Heater Innovations has approximately 300 Rollguard cradles in use, all of which have held up very well, Bayer said. With an estimated annual production of 60,000 Rheem Marathon water heaters, ranging in size from 15 gallons to 105 gallons, each cradle has withstood considerable action.
Most importantly, since Water Heater Innovations began using Rollguard cradles, the company has not experienced tanks sticking to each other.
Many customers view the all-plastic Rheem Marathon water heaters, produced by Water Heater Innovations, as best-in-class. With no metal in the water tank, there are no corrosion issues. Now, with the help of Rollguard cradles, the production of these innovative water heaters includes a best-in-class manufacturing process.