Tension-control retrofits among most popular

Goal still to boost performance of existing machines.

By Managing Editor Melissa Larson -- Converting Magazine, 7/1/2004 2:00:00 AM

While most converting machines are designed and built to last for decades, there's little that can't be improved upon with judicious upgrading and retrofitting. That's particularly true for web-handling situations, from printing to slitting and rewinding, where tension control has failed to keep up with customer quality demands, or where web-handling problems are causing line downtime.

Tension-control upgrades are among the easiest and fastest ways to breathe new life into older converting equipment, and they can yield immediate benefits in efficiency, print quality, and reduction in operator "tweaking," as the following success stories illustrate.

No tweaking necessary

Manufacturing beverage carriers from 13 mil LDPE presents it own set of converting challenges, but also some of the same concerns as any other web-handling operation—among them tension control.

ITW Hi-Cone, headquartered in Itasca, IL, dominates the market for can and bottle six- and eight-pack carriers. The company was able to increase productivity on one of its winder lines by retrofitting tension transducers and a customized automated tension-control system with flying-splice sequencing control circuitry for a four-shaft three-roll splicing rewind. The supplier of the tension control equipment was Dover Flexo Electronics, Inc., Rochester, N.H.

"We needed a tension-control solution that could run by itself, without constant knob-tweaking by the operator," says Steve Jones, Hi-Cone's corporate electrical engineer. The retrofit was installed in 2000 at the company's Charleston, IL, plant, one of three whose operations Jones oversees. Dover Flexo engineers worked with Hi-Cone's Charleston plant maintenance staff to install the tension transducers and tension controllers.

As the rolls exit the slitter station, dead-shaft idler rolls equipped with Dover Flexo Model C tension transducers installed on the shaft ends communicate with SteadyWeb tension controllers mounted on the turret control cabinet.

By allowing the machine operator to unload full rolls and load empty cores onto the free shaft of the rewind turret without ever stopping the machine to do the roll hangouts, routine downtime at the rewind is also eliminated.

"From our perspective, our engineers at DFE found this special automated splicer/ controller project to be an extremely interesting challenge," says Mark Breen of Dover Flexo. "Up until this time they had only ever developed a splicer tension controller for a dual turret rewind. The four-shaft rewind represented an extreme modification in terms of sequencing logic complexity, so we were all relieved when our engineers pulled it off."

"For an investment of about $60,000, we have an efficient tension-control system that does not require operator intervention," says Jones. "We also have received fewer customer complaints about inconsistent tension on wound rolls. We are considering similar systems for our other two plants."

Success with concentric circles

Astor Chocolate Corp., Lakewood, NJ, a 50-year-old candy maker who took its wrapper and label printing in-house about five years ago, needed better tension control to take the next step in narrow-web printing quality.

"We actually started looking for a press that could meet our demands in terms of printing tight register high quality four-color process," recalls printing director Tom Rouze. "Meanwhile, I received an email regarding a tension-control system webinar from MAGPOWR. I was so impressed with the presentation and the answers to concerns I had that a demo was set up ASAP.

"The system was adapted relatively easily," Rouze continues. The retrofitted Cygnus tension-control system was installed on the converter's 10-in., eight-color Mark Andy printer. "I was very impressed that MAGPOWR technical support walked me through, step by step, after-hours to make the necessary adjustments to be up and running the next morning so I wouldn't lose more production time than I had to.

"Armed with the basic knowledge to make adjustments, we were up and running the next morning." Later, in-house training for press operators enabled them to make fine-tuning adjustments.

"After one week to the day an order came in that would truly test the system," says Rouze. "It was an eight-color job, with four process and four spot colors. The customer's logo consists of concentric circles made out of process colors.

'Anyone who's been around awhile knows that trying to register concentric circles is one of the hardest types of registration to hold on any press. And as if that weren't enough, it's printed on a clear, 1.6 mil heat-sealable polypropylene, and we used a 1- mil self-wound polypropylene overlaminate.

"With a trap of only .005 in. in the circles of the logo, this proved to be a new challenge in itself. The general trapping tolerance for printing on paper is .007 in. and we were about to use a smaller trap on not just any film but OPP."

Press suppliers and outside consultants alike advised Astor that printing on film with such registration requirements would not be possible without substantial modifications to the press itself.

Rouze chose to remain optimistic. "For a few weeks when we printed on film we stuck to jobs of three colors with little to no registration," he recalls. However, he found that the new tension-control system made even such challenges as the eight-color concentric-circle job possible.

"This system has reduced set-up time and makeready waste dramatically," concludes Rouze. "When we start printing the start-up waste is just over the web length of the press at run speed. There are jobs now that run faster, with little-to-no registration adjustments for the length of the 7000-ft. roll. Our tension-control system from MAGPOWR was well worth the investment."

Bidding adieu to web breaks

Lofton Label, Inver Grove Hts, MN, is committed to quality products and on-time delivery. Managers believe accuracy is a key ingredient to quality output.

So when a label rewinder began to threaten delivery times, Lofton Label managers knew they must take immediate action. Tension problems resulting in perforation breaks were costing them time and money. Supervisors tried restraining the dancer arm, but even this failed to prevent web breaks. The converter was forced to reduce web speeds to prevent further breakages, and the slowed production wasn't meeting their goals.

Lofton Label needed a solution that would allow them to run at full speed and maintain the proper tension during accelerations, roll size changes and other disturbances.

To minimize tension variations and keep the dancer arm in a controlled running position, they turned to Nexen Group, Inc., Vadnais Hts., MN, for help.

Lofton retrofitted its label rewinder with Nexen's RSD200 Dancer Position Controller, a system that reacts quickly to tension changes during machine starts/stops, and handles rolls of varying sizes without readjustment. Once the RSD200 was installed and tuned to the unique characteristics of Lofton's label rewinder machine, it required no furthertuning.

Today, both plant managers and operators continue to be pleased with the results of the RSD200 system.

The new system provides Lofton with a stable dancer arm for the rewinder. Productivity has improved significantly, with the ability to run the line at higher speeds. Machine operators praise the system's ease of use and find the calibration extremely simple.

Lofton Label managers are now able to run their difficult jobs at full speed without the worry of web breaks. With all the functionality of this system, Lofton can easily maintain its commitment to quality and customer satisfaction.

"The Nexen RSD200 Dancer Controller has allowed our company to increase run speeds for our label rewinder, resulting in a 25 percent productivity gain. Operation is extremely simple and calibration is easy, because there is no need for operation adjustments. Currently we have the RSD200 on one of our three machines, but in the future our operators want this product on all our machines," says Steve Gaughan, Lofton Label's maintenance supervisor.

Making a retrofit pay off

In the four years Converting has been interviewing converters and suppliers about their successful retrofit projects for these July reports, a few common themes have emerged. Chief among them is this:

Retrofitting is not a shortcut. The same due diligence and homework needs to be performed in choosing a supplier and laying the groundwork as if the converter were building a brand-new line or buying a new machine. That means that some or all of the following questions should be asked:

• How long has your company been doing this type of retrofit?

• Can I get a list of references?

• What type of warranty do your offer?

• What level of technical support can we expect?

• How will you work with my maintenance staff?

• How will you train my operators?

• Do you have technical staff available by phone to help with problems?

• Can I get parts overnight if I need them?

Here are some other things to keep in mind as you plan your successful retrofit:

Business has ticked upward for machinery builders. Where one to two years ago they may have been quick to quote on your retrofit request, they may be a bit more busy quoting on new machines. Be patient.

Keep your overall goal in mind. That is, match the retrofit to the desired result. Is it greater accuracy? Higher speed? Better overall efficiency? If feasible or desirable, discuss it internally, then keep the main goal in mind as you discuss your retrofit options with suppliers.

Don't forget safety upgrades. If guarding, automatic shutoffs, controls, etc. are required as part of the overall upgrading of your machine, your retrofit vendor will advise you, but you should also consider any optional safety feature that will let your personnel operate the machinery more safely.

Also, keep in mind that the upgrades will by their very nature change the way your operators approach and interact with the machine and its guarding and surroundings. Be sure they are trained on the upgraded machine as if it were new.

Avoid overkill. Lastly, beware of paying too much for that last percent of improvement in speed or accuracy. Reducing waste from 2 percent to 1 percent can cost as much as it did to reduce waste from 50 percent to 2 percent.

Here, as in many other retrofit situations, is where it can be valuable to have a supplier you can trust to tell you where your money is well spent, and where it's wasted.

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