Coating Blades Pressure

Appropriate blade pressure ensures close contact between the coating blade and the coated surface, efficiently removing excess coating liquid and achieving uniform coating thickness. Both insufficient and excessive pressure will cause coating defects, as shown in Figure 5.

In actual production, the blade pressure is generally set within the range of 200～400 kPa. This interval is applicable to most coating scenarios and shall be adjusted according to on-site working conditions.

Figure

Figure 5 Schematic diagram of excessive and insufficient blade pressure

Coating Blades Thickness

The thickness of the blade body affects overall blade performance and service life. Ultra-thin blades with a thickness of 0.1~1 mm are adopted for high-precision coating applications. For conventional coating processes, the common blade thickness ranges from 1 to 6 mm. Blades over 6 mm thick are selected for high-viscosity coating fluids or working conditions requiring high mechanical strength and operational stability.

Coating Blades Sharpness

Blade sharpness is determined by multiple factors including material, blade edge angle, edge profile, manufacturing process, as well as daily operation and maintenance. A sharp blade can better scrape off redundant coating liquid and guarantee coating uniformity and surface quality. Currently, there is no unified quantitative standard for sharpness evaluation, which is usually judged empirically.

A blade with high sharpness can remove excess coating liquid smoothly and stably, delivering a smooth and even coating surface. On the contrary, sticking action, coating scratches and uneven coating during doctoring indicate insufficient blade sharpness.

Coating Blades Flatness

Blade flatness refers to the smoothness of the cutting edge and working surface under operating conditions, without undulation or depression. An uneven blade edge will directly result in inconsistent coating thickness.

Coating Blades Operating Speed

Blade operating speed affects the residence time of coating liquid on the substrate and the final coating thickness. A higher running speed boosts production efficiency, while excessive speed may lead to uneven coating and bubble generation.