A rotary gear motor, or gear box as it’s often called, has helped increase the cycle and fill speeds of KHS-Bartelt’s new RPM-ST (stacked-turret) horizontal form/fill/seal pouch machine.
The TPM rotary gear motor, from alpha gear drives, combines a brushless AC servo motor with a low-backlash, high-precision planetary gear head. The complete alpha gear unit is about the size of a basketball, though cylindrical in shape, and weighs less than 82 lb. It’s mounted beneath the main drive system of the 10-station turret, so it takes up little space.
“It drives the indexing-motion turret,” explains John Barrett, KHS-Bartelt’s mechanical engineering manager.
Without the gear motor, “there could be an inconsistent index at each station,” says Randy Uebler, the equipment maker’s director of engineering and operations. “Potentially, the other mechanisms that are working in unison with it could crash. The gear motor provides accuracy, and it’s hooked directly to the turret.”
KHS-Bartelt delivered the first of its next-generation RPM machines late last year, says Rick Manning, director of sales, pouch packaging. It’s being used to fill beef jerky packs. Right now, the third machine is being built at the company’s Sarasota, FL, facility. “The initial machine is running 24/7 at 60 to 62 cycles per minute,” says Barrett.
That’s a considerable improvement over the 45 mechanical cycles/min of the previous RPM machine, whose first generation was built in the late ’80s. Barrett says the main servo control system for the six-axis machine is from Bosch Rexroth’s Electric Drives and Controls Div. It controls motion, timing, and position functions. The single-axis gear motor communicates with the Bosch Rexroth system through a Sercos loop, relaying information such as torque, position, and speed.
“We’ve used alpha gear drives before for other applications,” says Barrett. “So when we were developing this machine we asked them to look at this application and recommend a unit that could fit the space we needed and handle the demands of our customer. We’ve had zero issues with it.”
For KHS-Bartelt, says Manning, the gear motor allows for “a reduced amount of repair and replacement parts. All of the line shafts, bearings, and older-style drives or motion parts are no longer required, and that creates dollar savings.”
Uebler says that while the customers wouldn’t likely point to the gear box specifically, “they do recognize that it contributes to the overall efficiency and reliability of the machinery.”
