It's the Little Things That Count

Doctoring systems have several interconnecting elements that lead to successful print jobs.

March 2008 by Chris Mc Loone

multipage

The evaluation and approach turned out to be accurate. By incorporating the Soft Blade into its process, this W/S Packaging facility has realized a $350,000 cost savings during the last three years.

Clear Lam Packaging, Elk Grove Village, Ill.

MDC began working with Clear Lam Packaging to resolve its scoring issues in 2006. When Daetwyler initially went into the Clear Lam plant, the presses were developing score lines on three to five rollers per month. Because Clear Lam was printing high-end graphics with high anilox line screens and low volumes, the company was printing with thin ink films to achieve optimized graphics. The process to troubleshoot and diagnose the proper solution began by altering many of the variables, along with Clear Lam’s respective suppliers. MDC and Clear Lam investigated anilox rolls, end seals, and doctor blades as either individual or as a combination of factors that were magnifying the vulnerability of the anilox roll scoring. Upon initial consulting with Clear Lam’s pressroom technician, MDC found that the company’s presses were in great shape. All decks were within the OEM specifications and the washing systems worked correctly. At this point it became evident that the doctor blade was a much more crucial element in the process, so Daetwyler set out to develop a solution. Over time, MDC has performed numerous doctor blade tests within the flexo printing market. It discovered that while magnets and filters are necessary for keeping the inking system clean and free of debris, this variable alone will not prevent excessive blade wear and contamination from the steel. MDC’s answer to the problem was its Soft Steel doctor blade.

This solution quickly eliminated the high costs caused by the press downtime required to perform roller changes and the negative effect it has on the print quality, not to mention the soaring expense of replacing rollers. The positive news is that by using the Soft Steel doctor blade, Clear Lam removed the blade as a variable to scoring issues. To that end, Clear Lam celebrated a ­score-free 2007.

Doctor blade holders

Doctor blades themselves are not the only components to look at. Sometimes it’s not the blade itself that is the problem, but the apparatus holding it.

The Fres-co System USA, Inc. ­Telford, Penn., plant had presses using heavy 61 3/4˝ long manual screw-clamp doctor blade holders that required lots of time, caution, and difficult lifting and handling. They also required 3˝ wide doctor blades plus backer blades. There were some print problems associated with flat contact angles related to the excess flexibility of the blade/backer combination relative to the requirements of the cylinder (size), ink parameters, and line speed. The Allison Systems wedge-lock™ holder replaced the “heavyweights” and after a significant time in service, revealed the following:

• The specialized wedge-lock™ blade clamping clamp-locking system is fast, effective, and easy to use, and it doesn’t “wrinkle” the blade. The “Quick-change” feature lets Fres-co replace coated-tip “longer-life” blades with “standard” steel blades, eliminating some cylinder wear on its jobs.

• The lower holder jaw incorporates an easily replaceable but durable O-ring seal strip to avoid ink contamination of the holder jaws, and the jaws easily slide apart to facilitate inspection and cleaning when needed.

• No backup blade is required. An effectively shaped nose piece provides the right stiffness with a lower cost 1 1/2˝ wide doctor blade alone.

• The nose piece pre-angles the blade to the cylinder for easier setup/positioning as needed for a clean wipe on the press.

• The Allison holders are significantly lighter than the originals, are much easer to handle and install, and have proven durable in service.

• Because the payback on these custom holders was real and there was value added in production, Fres-Co is looking to retrofit an additional, but different, press with Allison Systems custom blade holders.

Staying competitive

Properly maintaining your doctoring systems will help ensure quality print jobs 100 percent of the time, which will keep you competitive. “For us, the conversion to the doctored system was a simple decision,” says Ron Engebos of Fox Converting, Inc. “In order to be competitive in today’s market you need to consistently supply your customers with a quality product at a fair price. The doctoring systems provide you with the ability to supply these. The doctored systems greatly enhance the quality of your product in that they control the amount of ink to the printing plates.

“With a consistent supply of ink, the press operators are not over- or under-impressing the plates, creating excessive plate wear and inconsistent print images. This allows you to consistently produce high-quality products over a longer period of time. At the same time you are controlling your costs [since] the life expectancy of your plates will increase, your ink consumption becomes more predictable, and your waste is reduced. When the difference in the marketplace can be pennies, this certainly gives you an edge.” pP

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