What is the purpose of metal doctor blades, and how do they differ from steel ones? These blades have a carbon compound and the same chemistry but go through different treatment processes to ensure their quality. There are also three types of metal doctor blades: rounded-edge blades, graphite composite blades, and steel. Each one serves a specific purpose. Below, we discuss each kind.
Steel doctor blades
There are several advantages to having a steel doctor blade or metal blades, but how do you determine if a doctor blade is suitable for your situation? To begin, you should first determine the doctor’s blade’s breadth. This is because the blade’s capacity will differ from the primary body’s cross-sectional area. This cutout will typically be in the first corner of the basic body. Then, determine the thickness required for the blade.
Regardless of the material used for the blade, it is essential to consider the microstructure of the steel. The microstructure of steel is primarily determined by the treatments applied, such as hot rolling, cold rolling, and tempering. These treatments have different effects on steel performance, so it is crucial to determine the exact sequence, magnitude, and duration of the various treatments. These characteristics can vary dramatically between different steels, even those with the same chemistry. Other considerations for a steel doctor blade’s performance include its precise straightness and edge finishing.
Steel doctor blades serve several essential functions in gravure printing. While they are inexpensive, they are durable and provide triangular benefits. They also give a sharper edge for removing ink from the anilox roll. In addition, they are stiff, eliminate flutter, and maintain the image quality throughout long runs. Therefore, they are essential in flexo printing and gravure printing and must be installed correctly in your equipment.
Graphite composite blades
Graphite composite blades have similar properties to glass-composite edges and are designed for flexo applications with lower-LPI screens and laser-engraved ceramic anilox rolls. They provide excellent lubrication and long life for abrasive water-based inks. In addition, graphite blades have a unique seal relief shape that reduces the likelihood of end-seal distortion and ink leakage.
The abrasiveness of a metal doctor blade is usually determined by the composition of the composite layer, which tends to be a higher percentage of fibrous material than carbon fiber or graphite. The ratio of fibrous material to resin also influences the abrasiveness of the blade. The greater the fiber’s longitudinal length, the more uniform the wear. And the lower the percentage of nonabrasive fibers, the less likely it is to cause roll damage.
The invention is not limited to these types of doctor blades. Other doctor blades may be used in different industries that use rolls. A skilled craftsperson can modify the invention to meet the needs of specific industries. For instance, a graphite-composite doctor blade may also be used in the web-manufacturing industry. In addition, various modifications will be apparent to those skilled in the art.
Rounded-edge blades
Metal doctor blades with rounded-edge sections can be produced in various ways. In addition, a plurality of doctor blade breadths may be produced by planing, separating, grinding, or milling. The working edge of a doctor’s blade may be rounded later, depending on the desired thickness. In series production, the cutting edge is preferably shaped so that rounding and reduction of the material thickness coincide.
A typical blade comprises a bare body 100 in the form of a strip and a rectangular cross-sectional area 101. The basic body is hatched to indicate that the section is a strip and is also depicted as a frayed strip. The working edge is machined after separating to achieve the desired shape and quality. Alternatively, the doctor blade may be finished differently, or it may be shaped and coated.
Various manufacturers offer different types of blades. Allison Systems is one such company. They have been manufacturing cutting blades for over 46 years and have become a global supplier of doctor blades and related products. A typical blade should fit tightly and securely without creating waves. The blade should be selected based on the specific role to avoid excessive ink loss. If you plan on using a doctor blade with rounded edges, choose the one that fits snugly without leaving waves.
