Flexo press builder uses servos to demo hi-res printing
WHEN YOU put on new eyeglasses or contacts for the first time, everything seems almost unnaturally clear and crisp, and you realize what you’ve been missing. That’s what it's like looking at labels put out by Mark Andy Inc.’s new XP5000 narrow-web flexo press. The resolution is almost painful.
So what allows an approximately 50-year-old web printing machine manufacturer to suddenly push its resolution to ±0.003 in. from the more typical ±0.005 or ±0.006? Ironically, it’s good old attention to detail, really listening to customers, and a new application of increasingly affordable servo technology.
|CRYSTAL CLEAR LABELS|
Joel Panhorst, print services technician at Mark Andy, shows how Rockwell’s ControlLogix software and Kinetix drives hold color print registration to ± .003 in. on his firm’s XP5000 narrow-web label printing press at Automation Fair 2005.
James Wachtel, Mark Andy’s senior controls engineer, reports that users had asked it to incorporate servos in its presses because the technology reportedly could help boost printing registration control and improve resolution. For printers’ own clients, this means sharper images that can set them apart from their competition, particularly those putting labels on wine bottles. A servo-controlled press also allows quicker print-run set up and less media and substrate waste, which can be a huge, mounting expense for printers doing many short-run jobs, sometimes as short as 10-15 minutes.
To fulfill these needs, Mark Andy’s engineers and staff took about one year to develop the XP5000, which incorporates Ecodrive servos from Bosch Rexroth and PanelView and RSView operator interfaces and ControlLogix PLCs from Rockwell Automation.
“It used to take a printer three or four press lengths, typically 150 feet of material, to get through their press just once during set up,” says Wachtel. “XP5000 keeps this process very simple. The operators interface walks the user through set up, and basically tells why and where to fix problems 1, 2, 3 or whatever before starting to print. This simplifies the whole process, which helps users take advantage of it.
“When I used to do consulting with printers, they said that keeping a new machine simple will help users embrace it. A complex machine may be very elegant, but operators won’t use it because they usually don’t have the time to understand it.”
In addition, XP5000 uses a Sanyo Denki motion controller programmed with Mark Andy’s patented algorithms. “Most motion controllers have canned algorithms and built-in registrations for tuning on or off. We decided to write our own algorithms because we felt they could respond quicker and hold tighter,” explains Wachtel. “This can help smooth the printing process and find burps, so the operator can adjust errors before they get worse, and then not have to chase as many areas on the press.”
XP5000 also is Internet-capable with a secure firewall and password verified through Mark Andy’s server and its virtual private network (VPN) connection. “This means I can sit at my desk or wherever, log onto any of our presses, and troubleshoot them remotely. Anything I could do while physically at the operator station, I can do remotely via the Internet. Once you’re authenticated by the VPN, it’s like you’re there at the machine,” says Wachtel. “In fact, one of XP5000’s beta users noticed that his print color was ‘walking away,’ and we saw remotely that the RPMs weren’t in synch. We found that one printer station was pulling 10 times as much torque due to a loose coupling, and so the whole problem was solved in 40 minutes from shutdown to restart, and saved me from having to take an airplane trip.”
Not content to rest on its accomplishments, Wachtel says Mark Andy is toying with the idea of adding high-resolution web cameras to allow remote press inspection. “The big thing we had to do was to wait for servo prices to go down, and they still aren’t as inexpensive as big AC motors. So there are some things we may do with AC motors, or we could go all servos in the future, which would help us handle increasingly lighter films,” he says. “Servo-based presses have fewer gears than machine-driven presses, so there’s less chance for wear. More intelligence in the press allows better preventive maintenance and monitoring, and better recordkeeping means we know how long every motor has been running and when each needs lubrication. This preventive maintenance means users can run longer if the components are still okay, and schedule repairs around jobs, instead of interrupting them.
“The reason for all of this is to make better quality presses for our customers, and so we can better serve their needs.”