Precise Automation Required for Pick-and-Pack Machine

Using

By David Greenfield, Editor-in-Chief

Hamrick Manufacturing is well-known in the packaging industries for its end-of-line equipment, such as case sealers, packers, and erectors, as well as pick-and-place machinery and specialty equipment. The company works with several automation suppliers to create its equipment, so when a customer wanted a machine developed to pick and pack a variety of di erent protein powders in containers with intricate and delicate labels, Hamrick realized this new machine would require precisely controlled automation to protect the labels and allow for fast and easy changeovers between di erent products.

This customer runs “about 20 di erent SKUs on this line," says Je Eckstein, controls engineering manager at Hamrick. "They could run one product for a week or two straight, then they might run three di erent ones in a day. They wanted to speed up the process and remove any sort of operator error during changeovers” by automating the process. The customer’s fillers run 40+ bottles a minute, so any delays in changeover add up to a lot of bottles not being processed.

To create this pick-and-pack system, the first item on Eckstein’s list was to find powerful, compact servo motors for it. He reached out to Shaltz Automation, a supplier of Mitsubishi Electric equipment, and found the HG-KR23K servo motors to be a good fit for this new design with their 3000 rpm and 2.0 newton-meters of torque. The motor’s dimensions are 60mm x 77.1mm x 76.6mm (WxHxD) and it weighs 0.91kg. The torque level of the HG-KR23K is twice what Eckstein was expect- ing from a compact servo motor.

The HG-KR23K servo puts motion control logic within the drive itself, taking the load o of the PLC and simplifying programming.

Sizing of the motors was critical, because we’re “putting them inside of a 17-axis mechanical assembly that really didn't leave much room for motors," says Eckstein.

The new machine also uses Mitsubishi Electric FR-E800 VFDs (variable frequency drives) and an EtherNet/IP amplifier. The FR-800 series feature auto-tuning with induction and permanent magnet motors, can switch between multiple Ethernet protocols without the need for additional cards, can operate in ambient temperatures from -20°C to 60°C (-5 to 140°F), and the control card is conformal coated to withstand harsh environments.

The EtherNet/IP amplifier is another important component of the new machine’s design as it allows a non-Mitsubishi controller to work seamlessly with the Mitsubishi motors and drives.

"The thing that I really like about the EtherNet/ IP integration between the PLC and the Mitsubishi Electric drives is that all the motion control is done inside the drive,” says Eckstein. “All the behind the scenes work that it takes to make a servo go from point A to point B, plus how fast it gets there and how quickly it slows down—the math, the algorithms and the programming—it all gets taken care of inside the servo drive. That means the PLC can be non-motion rated, so we could go with a much less expensive PLC."

The use of Mitsubishi Electric motors and drives on this new machine deliver greater accuracy, says Eckstein, as well as greater output “because the motors are less likely to fail." Plus, the new machine will dramatically reduce changeover time from 30 minutes to 40 seconds, according to Eckstein.

"[For this machine] we just standardized on Mitsubishi Electric components," Eckstein notes. "And the machine that we ultimately developed has enough precise control to softly place each package. It's extremely gentle."

Read about an OEM’s head-to-head test of servo vs. pneumatic actuators.

Listen to this podcast discussing the di erences between standard and inverter duty motors.