This application was featured in Control Engineering's cover story.
To re-establish a laminator’s typical production rates, a company chose to complete a partial retrofit of the controls technology on the machine, which is an adjunct system to the main press. New controls added an estimated 10 years to machine lifespan, avoided $70,000 in parts costs, and increased output by 75%, among other benefits. This is part of the Control Engineering March 2015 cover story.
An industry supplier of flexible packaging—used by medical, pharmaceutical, consumer products, and food companies—recently began experiencing issues with the laminator component of one of its flexographic printing presses. The unreliable laminator, which has its own controller and human machine interface (HMI) operator screen, severely limited the entire machine’s production capabilities. Machine life was extended an estimated 10 years, output increased 75%, and $70,000 in parts costs were avoided.
To reestablish the machine’s typical production rates, the company chose to complete a partial retrofit of the controls technology on the laminator, which is an adjunct system to the main press. The laminator received a new motion logic controller and HMI platform.
Challenges Point To Retrofit
The company uses the flexographic, 25-year-old printing press, to print on poly film for items such as fertilizer bags and chocolate chip bags. The mechanics and existing servo drives and accompanying servo motors on the six-axis laminator were able to perform at the levels required; however, the controller electronics had become obsolete over the years and experienced intermittent issues that often slowed or halted production for extended lengths of time.
The company decided to proactively find a solution before the problem got worse, which could have necessitated a costlier and more complex solution as well as lengthier downtime. During consultations, some companies recommended a full retrofit or even a full machine replacement. However, the packaging manufacturer wanted to avoid major unplanned upgrades because those would require more investment and increased downtime.
We needed a retrofit solution and "it was a unique challenge for us," said Paul Szeflinski, engineering manager at VMRA. "It’s not often that we see such old drives and motors still in use. We wanted to reuse as much as possible, because the mechanics were still good and because it was the most cost-efficient option. The fact that we had very little time and that all the work had to be done on-site added to the challenge, especially since the machine is three stories tall."
The company worked to determine if the existing equipment could be reused. From there, it was recommended that a partial controls retrofit of the laminator and an incremental upgrade of equipment, which would require less downtime and would be less expensive.
Older Machine, New Components
The specific aspects of the partial retrofit solution were decided through teamwork between VMRA and the automation vendor.
The first step was to replace the control platform. While the controller was still in good working order, the computer terminal screen to which it was connected had become almost unreadable from age, which in turn made the overall system unreliable.
A new controller and HMI were selected for operator control on the laminator.
To handle the signal conversion between the older existing analog servo drives and the newly installed motion logic controller, VMRA incorporated a housing component into the controls platform. Located in the control cabinet with the drives, the housing for control section provides the physical framework where an individual drive system control card, or section, could be inserted to provide the analog conversion for the master encoder signal between the drives and the motion logic control (MLC). The controller also performed signal conversion, instead of purchasing and installing an extra drive to provide this functionality.
To complete the upgrade, a faster input/output (I/O) card compatible with the MLC replaced an older I/O card that was used with the prior controller. The upgrade to a faster I/O card enabled these components to operate at maximum efficiency.
In total, the controller, HMI and I/O card for the laminator were upgraded. With these modifications in place, the system now has a complete controls architecture that can effectively communicate with all the existing servo drives and motors.
Greater Output, Longer Lifespan.
The process was fast and required little downtime; the retrofit was completed and the machine was back up and running within a week. And because the newer technology takes up less space than the older equipment, adjusting the control cabinet was easy, too.
In the end, the retrofit was exceedingly successful and provided significant cost savings. Szeflinski estimated that the company saved some $70,000 in parts alone by opting for a partial retrofit rather than a full retrofit.
"The retrofit helped our client protect its existing investment in the equipment," Szeflinski said. The retrofit is already paying off. The manufacturer wanted the machine to function for at least another two years. Instead, it will be usable for at least another decade, and the new controls platform is expected to last at least another 20 years.
The retrofit also boosted output. The machine in its new state had a material output of 800 to 900 ft per minute. With its ongoing issues, production had been down to about 400 ft per minute. Now, it’s back up to approximately 700 ft per minute, close to its original output and a 75% increase from its previous output capability. It also has improved reliability, reduced maintenance costs, and provided an overall boost in performance.
The company plans to continue performing incremental upgrades to the machine, and the new hardware allows for that.
Workers are looking into putting a remote secure connection on the machine, which would enable capabilities like remote backups. This upgrade, which is compatible with the MLC, would cut down on travel time as well as safeguard against a system failure. This function was unavailable with the original controller that the printing press previously used.
There are four other laminators with similar setups that automation vendor would like VMRA to upgrade in the near future. "A partial retrofit is an ideal solution for companies using legacy equipment," Szeflinski explained. "When done properly, it protects investments while keeping production rates high, with very little downtime."
Controller retrofit summary, benefits
Replaced outdated controls platform with modern motion logic controller
Added a housing for controls to ensure communication between older drives and new controller using existing automation bus
Upgraded HMI to newer graphical interface with touchscreen capacity
Replaced older I/O card with newer high-speed I/O card
Added 10 years to machine lifespan
Avoided $70,000 in parts costs
Increased output by 75%
Improved reliability, reduced maintenance
Required minimal downtime for controls retrofit
Saved space in control cabinet with newer technology
Supported comprehensive, efficient code for motion control.