Pfankuch Machinery, based in Ahrensburg, Germany, is a leading manufacturer of friction feeder systems for inserting leaflets and products into sales packaging. An embedded smart servo drive from Metronix (part of the Apex Tool Group in Sparks, MD) has allowed Pfankuch to increase the speed of its latest friction feeder — the SmartFeeder — by 50% while also doubling the positioning accuracy. This offers a massive gain in productivity for the many users of this type of packaging equipment in markets including pharmaceutical, and food and beverage processing. At the same time, the new embedded drive minimizes the hardware costs of the upgrade for Pfankuch, because the drive was adapted for the application, providing a stripped-down product suitable for OEM integration that eliminates numerous expensive components.

A smart embedded drive provided an increase in performance for friction feed packaging machines.
Pfankuch upgraded the control hardware as part of an exercise to improve the performance of one of its most popular friction feeders in the mid-range sector of the packaging equipment market. The upgrade project targeted the motion control element of the packaging machine, as the basic mechanical structure of the SmartFeeder is reliable. Before the upgrade, the general-purpose friction feeder offered an insertion capability that performs real-time registration and inserts items at up to a maximum speed of 100 items/minute, to a position accuracy of nearly 2 mm. The motion control hardware used to achieve this was a brushed DC motor and a relatively simple drive that was designed and manufactured in-house at Pfankuch.

Pfankuch wanted to improve speed and precision as much as possible, while also changing the motor type to a brushless AC servo to eliminate maintenance and help speed acceleration times. Crucially, the electronics upgrade had to be achieved without increasing manufacturing costs by more than a small margin in order to keep the machine price-competitive in its market segment.

The key factor in the upgrade was finding a suitable servo drive. Most servo drives tend to be offered as complete packaged products, and these are far too expensive. However, when the packaging OEM approached Metronix about a drive from its smart DIS-2 range for decentralized applications — which offered an ideal control platform for the single axis in this feeder — Metronix adapted the drive for embedded use to reduce costs and simplify integration. This made the upgrade project feasible. Metronix also provided engineering support to help Pfankuch implement the changes to the motion control subsystem.

Metronix’s smart embedded drive mounted inside Pfankuch’s new friction feeder.
The optimization exercise involved stripping out all non-essential components from the DIS-2 drive. This included eliminating the casing and expensive system-level connectors. Metronix then added application-specific connection and mounting, and made some modifications to the drive’s firmware to optimize performance. Metronix’s resulting brushless AC servo drive solution increases Pfankuch’s friction feeder insertion speed from 100 to 150 items/minute, while simultaneously doubling positioning resolution to 1 mm. The embedded drive also provides Pfankuch with a CANopen port to provide a platform for future enhancements of the feeder. The packaging machinery OEM also has the option of adding daughter boards later, which could provide additional fieldbus interface options such as EtherCAT or Profibus.

One of the key ways in which the Metronix drive improves the speed of the friction-fed insertion cycle is through local control intelligence embedded in the DIS-2 drive, which both performs the control calculations more rapidly, and employs a more sophisticated positioning algorithm that adjusts drive speed much more often to enhance registration resolution.

The feeding speed and precision positioning performance of Pfankuch’s new SmartFeeder system was improved by such a large margin that it competes with high-speed feeder systems in applications that do not require multi-axis control. This higher-performance product category typically includes a powerful dedicated motion controller or PLC, and tends to cost at least twice as much as standalone friction feeders. In addition to improving performance, Pfankuch has also made a number of improvements to the feeder to simplify operation and use; one of the most important is a very easy means of changing the friction belt to suit different insertion applications.

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