Traditionally, doctor blades would be filed by the printer. Today, you can purchase plastic and metal blades with a pre-cut edge to provide precision and consistency during printing. Here are some of the different edge options and their unique qualities.
Beveled or Lamella
When manufacturers first started making pre-cut blades, they would always create a 15-degree slanted edge called a bevel. However, this design’s footprint can change drastically during one printing job, leading to variations in the finished product. The result was the development of the lamella edge. While this shape doesn’t have the hardiness of a bevel, it wears much more consistently. Today, you can also find beveled edges with two- to five-degree edges. These have the hardiness of a bevel and a more consistent wear pattern like the lamella.
They can also be found without a beveled edge, known as square blades. These are basically raw blades that don’t always have a working edge. Instead, square edge shapes typically are made from plastics and are used for containment rather than doctor blades.
Round edge blades offer a precision working edge. They tend to be cheaper than the beveled or lamella edges because they don’t require as much machining during production. Although they do allow more ink to sit on the anilox roll during a printing job, they are the hardiest option on the market. This makes them the perfect option for printing with a rough anilox roll.
Whatever edge you prefer, it is important to choose the right one for your needs. If you need to apply high pressure to a job, be sure to choose something that can handle it without breaking, such as a hardy round edge. On the other hand, if you need fine work, you might choose a beveled or lamella edge.