Rosemont, Ill. — Seljan Co. Inc. had a problem: A massive amount of black liners for trash receptacles that needed a massive amount of trimming.
Combine that with employees who might be newer, and undertrained, and the numerous shapes of the liners, and Seljan was experiencing quality problems along with some injuries at its plant in Lake Mills, Wis., said Dru Laws, senior vice president of Seljan's plastics division.
The solution: Seljan developed its own finishing robot that could handle many different sizes.
Now Seljan wants to sell them to other rotomolders, Laws said in a presentation at Rotoplas.
The system uses a six-axis Yaskawa robot mounted on top of the structure which hangs down. A pneumatic fixture has four linear actuators that open and close to secure the liners, and can handle different sizes. Seljan purchased the robot and actuators, assembled it and did the programming.
“This is what I'd call a smart robot talking to a smart fixture,” he said.
Another version could have two fixtures on a turntable.
Trimming the liners had become a big challenge at Seljan, one faced by other molders.
“We have a labor shortage going on in the United States, and Seljan is not immune,” he said at Rotoplas.
Also, he said, employee turnover “has resulted in some undertrained staff. I see some heads nodding so I know it's not just a ‘Seljan problem.'”
Laws said Seljan can make 100,000 trash bin liners a year, in oval, round, square and other shapes. Employees trim each one, and sometimes have to cut out hand-holds on the side.
“We will mold, in advance, lots and lots of liner shells, and then all we have is a lot of liners lying around,” he said.
Seljan's rotomolding operators had to “scalp” the liners, a cutting process, to be able to stack them up.
“That initial scalping process was where most of our accidents were,” Laws said.
Now with the robot, operators can remain at the rotomolding machine and pass the liners to another employee, who sets them up in the trimming station, Laws said.
Laws said when Seljan officials first decided to have a trimming robot, they contacted automation companies for advice. But he said the experts preferred overengineered systems, and asked “stupid high” prices. So Seljan started a unit called Advanced Integration Technologies AT, to build its own. It is working well, and Seljan leaders decided to sell the rotomolding-specific finishing robots to other rotomolders.
Laws said router and adjustable fixtures cost the company about $150,000 — and that's the price point Seljan will sell one for. A router robot and the structure alone runs about $100,000.