By Peter Graham
Trends in manufacturing show a greater need for product diversity in addition to shorter run times.
But until recently, manufacturers and packaging companies looking to change a production line from one product SKU to another were faced with manually intensive machine adjustments and positioning that took hours if not days to complete. As a packaging automation supplier, we wanted to find a simple solution to reduce the excessive downtime for our customers, thus increasing their productivity.
Our initial thoughts were that we would build a solution to add to customers' existing machinery, but it ultimately required more than that, and finally was implemented as a retrofit to any machine that requires adjustments, provided the existing equipment contains or is compatible with up-to-date electronic components.
Our machine adjustments previously were made by air motors and hand cranks, but we chose to switch to servo motors because of their level of controllable positioning. The design of the servo motors provides a simplistic mechatronic solution for an industry that's technology-driven. However, we had a "wish list" the servo motor had to comply with to provide a safe and reliable product customers could justify spending additional money on, and in order to receive a healthy ROI:
- Low-voltage motor power (24 V, with no additional wireways required)
- Compact footprint
- Absolute position encoder, maintaining positional awareness over power cycles
- Integrated drive/amplifier in motors (eliminating the need for additional panel space)
- Seamless communication with existing I/O systems
- Independent motive and control power supplied (easy integration to existing safety systems).
We worked closely with Festo Canada's team to co-create the system solution, even making a trip to Festo's global headquarters in Stuttgart, Germany, to make sure we could create a viable option that manufacturers would buy into.
Festo engineers in Germany and Mississauga, Ontario, took their stock 24 V, dual-power CANbus MTR-DCI servo actuator, and modified it by adding an absolute encoder and DeviceNet chip. Switching from CANbus to DeviceNet eliminates the need for a hardware interface between the network and PLC. The benefit of an absolute encoder and integrated drive/amplifier provides Edson the ability to eliminate additional panel space on existing casepackers.
Six months later, Festo completed the Servo Adjust motor, and shipped it to our technology facility for system integration and testing on our SR3600 casepacker. In addition to the technology integration, we developed the software for the system.
The new solution enabled Edson to create an automated machine adjustment system with 100% position repeatability, high accuracy within <1 mm, and reduced startup scrap. Production line changeovers now take minutes instead of hours (view a quick changeover at www.ControlDesign.com/changeover). One touch of the HMI screen can initiate all servo motors to begin automation, making it easy for even inexperienced operators to perform tasks. "This provides us with the competitive advantage we were looking for in today's market," says Bob Krouse, Edson's operation manager. "Our customers understand the cost savings and believe in the quality products we supply."
We commercially launched the Servo Adjust system in October 2010 at Pack Expo in Chicago, and have since found significant interest in retrofitability to existing production lines. This is offering us greater business opportunities within new markets. Edson also continues to develop new innovations with Festo, improving on existing technologies.
Peter Graham is controls engineer supervisor at Edson Packaging Machinery (www.edson.com), Hamilton, Ontario, a machine builder that provides automation solutions for the packaging industry.