Servos Serve Up Filling Success
PC-based servo controls help dual-lane f/f/s machine maximize filling speeds and achieve easier changeover.
*Reprinted Courtesy of Packaging
In the process of developing its Delta Q16 form/fill/seal machine, engineers at Evergreen Packaging Equipment (Cedar Rapids, IA) decided to design it around servo technology from Bosch Rexroth (Hoffman Estates, IL) to achieve both faster carton filling speeds as well as easier changeover. Machine speeds have jumped from 200 cartons/min in older models to the current 300 cartons/min on the Q16. Shown for the first time in Chicago at the World Wide Food Expo in 2001, the machine is equipped with eight linear servo actuators, seven rotary servo motors, PPC controller, and SERCOS open architecture modular digital drives, all from Bosch Rexroth.
"A lot of the functions are similar to previous generations," says John Petesich of Evergreen. "But we designed this one with servos in mind from the beginning. We made a lot of changes and enhancements, speeding up the machine from many of our previous designs. That’s one of the main reasons we had to go with servos."
According to Petesich, one of the servo motors is what Evergreen calls the main drive. It runs a main shaft that operates some of the mechanical functions that go into forming the carton for filling. Most importantly, the servos help coordinate the motion between the indexing conveyors, the fillers, and the carton lifts.
"It coordinates that motion so they all move in time with each other to help us maximize the filling speed that we are capable of on that machine," Petesich says.
Bosch Rexroth's technology was necessary, he says, because of its central controller and fiber optic motion network that allows operators to carry out real-time control and adjustment of the servos as needed.
"The ease of being able to change motion profiles has been a big help to us," Petesich says. "Where we once would put in fixed metal cams for some of the functions that the servos are now performing, we can now fine-tune them and tweak them to different product types, whatever the carton size. We can have a much bigger matrix of profiles that we can use instead of having a fixed hardware cam."
On older machines, operators would have to slow down production to run certain products and certain carton sizes. The new control technology allows different profiles that enable operators to run the machine at maximum speed for all product types and carton sizes.