An Insurance Policy to Proper Printing
Much research and development has gone into the design of modern doctor blades and systems, and knowing what is needed is the most important factor in choosing the correct blade.
AUTOMATION. SIMPLICITY. PARTNERSHIP. These three elements are important to the converter involved in any aspect of the printing process, and doctor blades are no exception. "Fundamentally, the job of the printing doctor blade has not changed over the years. A doctor blade must remove excess ink from the ink transfer process without causing other problems," said Paul Sharkey, president, FLXON Inc. "What has changed is that more and more printers realize the doctor blade really does matter and that it is not a commodity."
If some converters still need to be sold on the importance of doctor blades to the overall printing process, some doctor blade suppliers offer suggestions and hints to choosing the right doctor blade, and offer some insight into the future of the doctor blade industry.
What to know
There are a number of factors that make selecting the right doctor blade a difficult proposition, says Perry Lichon, president, Retroflex Inc. "Through the years we have learned that no single blade material or tip configuration is best suited to all applications. This seemingly inexpensive piece of consumable can easily make or break the end user's profitability," he said.
"Imagine. A multi-million dollar printing or coating line having its performance being controlled by a thin strip of material that costs pennies per inch," Lichon added. He said a good way to research which blade is right for specific printing processes is to ask the supplier for samples of a variety of different blade materials.
"Printers need to partner with their blade, roller, and ink companies to solve their printing issues," said Tony Donato, blade application engineer and trainer, Benton Graphics Inc. "As the buyers of packaging become more demanding and the timetables keep shrinking when new products are needed, the converters are forced to turn to their suppliers to assist them within product and process development," he added.
Choosing the right blade material is almost as important as choosing the right blade manufacturer. The mechanics of the blade needs to be within specific tolerances to ensure proper positioning, which is essential to preventing ink leakage, ensuring a long blade life, and saving the anilox roll from unnecessary wear and tear.
"The doctor blade must be machined to the most exacting straightness and flatness tolerances to ensure the press operator can meter ink effectively with the lowest possible pressure settings on the doctor blade," said Anthony Foley, president, Converting Solutions Inc.
New technologies and trends
Although doctor blades have not dramatically changed in the past few years, there are some minute differences that, when added together, make a stronger, better product.
Bobby Furr, flexo services manager, Max Daetwyler Corp., said his company is focusing on "remedy blades" for common issues that converters and press operators deal with on a daily basis in the pressroom. First and foremost on this list, said Furr, is roller scoring. To combat this problem, Daetwyler has developed an anti-scoring blade with a nickel-based material that is resistant to corrosive inks and lacquers and protects the contact zone from oxidation. Another area Daetwyler is focusing on is the use of UV inks, which have a tendency to spit. Daetwyler has introduced "The One Step Blade," that is a non-spitting blade to be used with UV inks.
To help converters continually improve in this critical area of printing performance, doctor blade suppliers are introducing improvements at a steady pace. Below are some examples of those new products.
Prevent ink spitting, increase blade life
Converting Solutions Inc.
888-274-9906
Xcalibur X-99 is a unique doctor blade product that offers some distinct advantages to the flexo converter. This blade is chemically coating with a proprietary coating that enhances the performance of the doctor blade, prevents unwanted ink spitting with UV ink systems, and offers extended life in applications where abrasive pigments are found in the ink. Blade wear is very slow and predictable without the fear of anilox scoring.
Reverse angle system
Retroflex Inc.
www.retroflex.com
Retroflex's enclosed Reverse Angle Doctor Blade Systems (RADBS) are custom designed for retrofit to virtually all flexographic printing presses and gravure coaters. Most Retroflex systems are designed to fit to existing drilled and tapped holes, reducing installation costs, and providing a cleaner appearance.
Retroflex doctoring systems have applied a wide range of fluids including water-based, solvent-based, and UV inks and coatings. An optional reduction gearbox will assist with system positioning. True linear adjustment is also available for positive and repeatable doctoring and blade wear compensation.
Foam seal option for doctor blades
Benton Graphics Inc.
www.bentongraphics.com
Benton Graphics has announced the availability of a foam seal "FS" option for their entire family of doctor blades. The FS option is a licensed patented product that is primarily used for the PCMC NT chamber family. It is also helpful for leveling doctor blades in chambers that have a corroded seating area. The FS option now gives Benton's customers access to blades that solve printing problems, like excessive blade wear with white ink, and blades that corrode in extreme pH inks.
Also, Benton has recently released its newest non-metallic high-performance doctor blade, the Intimidator composite. The exclusive non-metallic composite has stiffness comparable to steel doctor blade material and is available in two thickness 0.021˝ and 0.016˝.
Low COF
Allison Systems Corp.
www.allisonblades.com
Gravure cylinders on long-running jobs, cylinders with large unengraved areas, cylinders with difficult vignettes, and cylinders with chrome issues often need a doctor blade tip with a lower coefficient of friction (COF) against the chrome than any doctor blade steel alone. For these applications, Supercoat™ doctor blades offer outstanding resistance to blade wear. A Superhoned Plus™ tip shape and precisely controlled coating parameters make this blade effective and economical.
Demanding graphics and long life
Flexo Concepts
www.flexoconcepts.com
TruPoint ProFlex™ is designed to handle demanding graphics while maintaining a desirable blade life. ProFlex lasts three to four times longer than traditional steel. Its stiff, thin tip meters just like steel without all the anilox roll scoring. The blade meters well on white inks and highly abrasive applications. The material is safe and will not cut the press operator's hands.
HIgh density, ultra refined
FLXON Inc.
www.flxon.com
FLXON is the exclusive distributor for Swedcut® doctor blades in Canada, the U.S., and Mexico. All Swedcut doctor blades are made from FLXON's proprietary/high-density M.Flex II steel. M.Flex II is a carbon steel blade, with a high-density, ultra-refined micro structure that achieves fine, low-friction metering/doctoring with minimum wear.
Improved quality, versatility, and speed
Harris & Bruno Int'l
www.harris-bruno.com
Harris & Bruno's standard chambered doctor blade system offers printers the latest technology for improved quality, versatility, and speed. The system gives printers enhanced capability in high viscosity, water-based, and UV applications, and substantially increases press speed without ink slinging. Compensation for blade wear saves money on blade replacements and pneumatic controls eliminates the need for electricity. Harris & Bruno also offers a multi-year warranty and retrofit guarantee.
Reduce score lines and streaks
Max Daetwyler Corp.
www.daetwyler.com
The new D-Line of coated doctor blades was developed by Daetwyler specifically for use in flexo and gravure printing applications to reduce score lines and streaks and to enhance blade, anilox roller, and gravure cylinder life. With these hardened coated blades, which have a thin, reduced tip, it's now possible to get longer blade life without sacrificing printing quality.
by Megan Wolf
Assistant Editor