Printing industry professionals are constantly looking for ways to optimize practices and materials to achieve greater productivity.
One development that has gained attention is the use of “exotic,” wear-resistant doctor blades made of ceramics. These blades have been shown to provide a significant economic benefit by increasing productivity, improving printing quality, and reducing waste.
In this article, we will explore the use of ceramic plasma-coated doctor blades, which significantly minimizes doctor blade and anilox wear and saves operational costs. Let’s begin with basic information. Doctor blades are an essential component of flexographic printing and coating processes. They are responsible for metering ink or coatings, ensuring a consistent and uniform application. As blades continuously interact with the moving surface of the anilox roll, the doctor blade is subject to wear.
wiping process with a ceramic plasma coated
doctor blade.
All photos courtesy of TKM
This wear can lead to inconsistent ink metering and reduced print quality from dot gain and other print defects that ultimately leads to increased downtime and higher operational costs, due to changeovers.
One recent innovation–a plasma-sprayed ceramic coating, applied to doctor blades to enhance wear resistance–reduces the need for frequent replacement or maintenance. it provides a significant increase in doctor blade life and produces a situation where you should never need to stop the press, due to your doctor blade.
Efficiency Enhancer
Plasma-sprayed ceramic coating is a process that involves depositing a thin layer of ceramic material onto the doctor blade, using a plasma spray. This layer increases the hardness, wear resistance, and chemical stability of the blade, prolonging its service life on the press.
Plasma-sprayed ceramic coatings minimize wear in doctor blades through several mechanisms. Ceramic coatings:
- Significantly increase the hardness and wear resistance of doctor blades
- Provide a barrier that resists abrasion as it meters an anilox roll
- Are specifically formulated to maintain a particular hardness ratio between the ceramic surface on the anilox roll and the coating itself– hardness of the ceramic surface on anilox rolls, consisting of thermally sprayed Cr2O3, ranges from 1200 to 1400 micro-Vickers
- Have a hardness of 900 HV, which ensures a durable performance and minimizes wear
- Result in doctor blades which last approximately 10 times longer than uncoated steel
- Affords improved ink metering over time and a reduction in press downtime
Doctor blades with plasma ceramic coating exhibit a lower coefficient of friction, which reduces the friction between the doctor blade and the anilox roll. This reduced friction minimizes the generation of heat and wear debris, further extending the life of the doctor blade and preserving the condition of the anilox roll.
This results in less chamber leakage and a more efficient printing process. With fewer blade changes and reduced ink cleanup requirements, labor costs are minimized. Additionally, plasma ceramic coated blades require less maintenance of ink filtration systems and magnets, due to the elimination of burrs, created by uncoated doctor blades. The consistent wipe of plasma ceramic coated blades, over a longer lifetime, prevents unscheduled downtime, reduces waste and ink consumption.
Another added benefit of a plasma ceramic-coated doctor blade is chemical stability. Increased chemical stability helps to protect the doctor blade from corrosive ink and coating chemistries often found in printing and coating processes. This stability prevents premature degradation of the blade and reduces the likelihood of chemical-induced wear.
Risk Reducer
Plasma-sprayed coatings produce a strong bond between the ceramic layer and the underlying doctor blade material. This adhesion minimizes the risk of delamination or flaking, ensuring that the coating remains intact throughout the blade’s use on the press.
Adoption of plasma ceramic coated doctor blades produces several compelling benefits for printers, converters and packaging manufacturers, including extended doctor blade life, reducing the frequency of blade replacement, and minimizing downtime. An additional safety benefit from using such long lasting doctor blades, is the reduction and the handling of sharp used doctor blades by 90 percent. Improved print quality leads to more consistent ink or coating metering, resulting in fewer defects.
You should never need to stop the press to change your doctor blade, and the extended service life of plasma ceramic coated blades translates to lower maintenance costs, as blade replacements and associated downtime are minimized.
Plasma ceramic coated doctor blades represent an effective solution for minimizing wear in the printing, packaging, and coating industry. By improving wear resistance, reducing friction, and enhancing chemical stability, plasma ceramic coatings extend the service life of doctor blades and provide numerous benefits for businesses. As a result, plasma ceramic coatings are an attractive option for companies looking to improve print quality and reduce maintenance costs.
Productivity Boost
The need to optimize the practices and materials in the pressroom and to strive for greater productivity is ever increasing. The use of state-of-the-art doctor blades can be a significant contributor to this goal, given their extreme long life and print quality improvement potential.
The effect of these doctor blades on an anilox roller surface is not only safe, but actually healthier in many ways, compared to conventional steel blades. With the proper design, and specification of the type of ceramic to match the anilox roller material surface, abrasive wear can be avoided, friction significantly reduced and metal slivers in the ink eliminated.
With these benefits in mind you will be able to increase the efficiency of production.
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