By Joe Morrissey, Conflex
The Renaissance period spanning from the 14th to 17th centuries was a period of rebirth—cultural enlightenment and learning—in western Europe. These days, the term is applied to everything from government to education, and most certainly to technology.
Our company, Conflex, a builder of shrink-wrapping machines, has undergone what many of us refer to as a renaissance. In 2005, Conflex began its own rebirth by substantially redesigning each machine in the product line and continued redesigning machines through the end of 2007. The company’s Modular CW and ServoFlex lines have undergone a complete mechanical and electrical redesign (Figure 1).
Conflex wrapping machines are tailored to the food, consumer goods, electronic media and printing industries, among others. Typical applications for our machines include wrapping for frozen foods, bulk packaging for club stores, CD and DVD packaging and the packaging of household products and toys.
Figure 1: The ServoFlex line had a complete mechanical and electrical redesign and now performs better, is more flexible to program and can teach operators how to use the machine with automated instruction.
Most of our builds are standard machines for the particular industry, but we also develop custom infeeds that connect to our machines to offer customers different ways to feed their product into our machines.
The ServoFlex wrappers use a DC motor to drive the infeed portion of the machine and all three servo motors follow the speed of this motor. The film feed and vacuum belt are run off a servo. Servo motion is well-suited for exact bag sizing—particularly for print registered applications. The discharge belt is driven by a servo that runs either faster, slower or the same speed as this vacuum belt so the individual packages can either bunch or pull away from each other. The last servo moves the seal head back and forth in a flying saw fashion. The seal head matches the speed of the discharge belt and then places the seal in an exact location by sensing the gaps between packages.
With our company motto—“Flexible people make flexible systems” —in mind, we sought a controls system that could deliver true application flexibility to customers in these diverse industries. Over the past five or so years, our customers had been asking our industry’s machine builders for increased flexibility, faster changeovers and easier operation, troubleshooting and remote connectivity capability.
“All of Conflex’s customers demand user-friendly machines with intuitive interfaces,” adds Mark Lorenz, Conflex electrical applications engineer. “New technology is a critical factor for us. Tough competitors in our field also are promoting the latest and greatest technologies, but ease-of-use also is a must-have.”
Choose Action, Not Buzz
When servo technology started generating a high level of industry buzz in the early 2000s, Conflex was one of the first companies to successfully incorporate it in shrink-wrapping machines. Today, as open, PC-based control and industrial Ethernet technologies make a similar commotion in our industry, Conflex is at the forefront to actually do something with it.
In particular, the ServoFlex film seal wrapper has been through dramatic changes since its previous incarnation. “The old ServoFlex design used numerous intelligent drives that handled the automation and motion control aspects of the machine,” says Lorenz. “The required programming time for multiple drive controllers really irritated us. This was a three-servo system, and each axis had a controller that had to be individually programmed.” The drives weren’t equipped for Ethernet connectivity either, which hampered needed networking requirements.
Adding or removing I/O further complicated the problem. “If even a single I/O point failed in the intelligent drive system, we’d have to replace entire boards,” adds Lorenz. “It also was very expensive to replace the drives themselves whenever we had a failure. It became apparent that to be flexible and better manage our controls, we needed a new solution.”
In late 2005, we had made what we thought was our final decision on a new platform from a major automation and controls vendor. “It was an acceptable motion controller with PLC functionality but didn’t have all the programming and design flexibility we hoped for,” recalls Lorenz. “We just accepted that we had to put more time and effort into the design than was ideal.”
We planned to order our controllers the following Monday. Don Seicther, Beckhoff Automation’s Wisconsin regional sales manager, called us the Friday before and explained how the Beckhoff product line might be able to help us.
We learned about Beckhoff’s DIN-rail-mounted embedded PC and IEC 61131-3-compliant automation and motion control software. “The solution turned out to be exactly what we were looking for and allowed us to create our ideal electrical controls system,” says Lorenz. “We were impressed enough that we decided to make a major course change at the last possible minute. With the perfect technological match with the openness and flexibility we wanted, the Beckhoff system costs much less than the other vendor’s system.”
We considered using standard PC components, but we didn’t consider them industrial enough, and we would have had to use several suppliers to get all the needed components.