What is a doctor blade and how does it work?
Doctor blades play a vital part in achieving high-quality and uniform print results throughout the job.Â
In closed chamber doctor systems, which are widely used in flexographic printing machinery, there are two opposite blades in action:
The doctor blade actively scrapes off excess ink or coating from the rotating anilox roller screen in the printing deck. This is crucial for an even dosage and transfer of ink from the anilox to the printing plate. The precision of ink application directly impacts print quality.
The retaining blade, also called containment blade, has a sealing function. It seals the chamber against the anilox roller over its length. The containment blade ensures that the ink or varnish remains in the chamber and lets fluid from non-emptied cells in the anilox roller pass back into the chamber.
The positive impact of well-suited doctor blades
Optimum doctor blade performance requires a careful choice of blade material and shape for the respective printing application. AGSflexo high-performance plastic and steel doctor blades support printers around the globe in boosting flexographic press productivity and efficiency. Benefits include:
Plastic and steel doctor blades
Our wear-resistant range of polyBLADE plastic doctor blades can handle all inks types and offer durable doctoring and proper sealing results. Since they do not grind in as razor sharp as steel blades, plastic blades increase the handling safety.
Our steelBLADE range of high-grade alloyed steel doctor blades with a finely ground blade profile allow for very accurate doctoring and continuously high printing quality. For special demands in terms of lifetime, special steel types can be used.
AGSflexo plastic doctor blade types
Ideal for containment
polyBLADE S
Ideal for large screens and volumes
polyBLADE U
Ideal for long print runs
polyBLADE P
AGSflexo steel doctor blade types
Ideal for solvent and UV inks and varnishes
steelBLADE C
Ideal for water-based inks and varnishes
steelBLADE S
Ideal for abrasive inks and varnishes
steelBLADE T
The final touch: Blade tip options
Besides the choice of material, the blade profile, i.e. the cut geometry at the doctor blade tip which is in contact with the anilox roller, is crucial for the performance of the doctor blade in the chamber. Different types of profiles can be machined depending on the material structure of the steel and plastics blades.
Plastic blade profiles
Bevel
Straight
Steel blade profiles
Lamella
Round tip
Bevel
Anti-Spit lamella
Our doctor blade solutions by print application
The choice is yours: Doctor blades in coils or pre-cut
By default, our doctor blades come in coils. Steel doctor blades are typically coils of 100 m (328 ft), plastic blades can be either 30, 50 or 100 m (98, 164 or 328 ft) depending on the material and thickness.
By using our bladeCUT service, you can however get them already precut in any required length. This way, you can insert them directly into the chamber.
This saves you time during the job setup and reduces material waste.
Tips for handling doctor blades
When installing doctor blades, make sure that the ground side of the doctor blade tip points to the inside of the chamber doctor blade system. The blade tip profile, e.g. lamella or bevel, should not be visible from the outside. Only then, an optimum contact between doctor blade and anilox roller can be ensured for clean and safe doctoring.
For the sake of work safety, we recommend to always wear protective gloves when handling doctor blades. Especially used doctor blades can get razor-sharp. Protective gloves help you to prevent injuries.
