Metering Rod Body Material
The body of a metering rod is typically made of stainless steel, such as 304 or 303 stainless steel. These materials offer excellent corrosion resistance and wear resistance, making them suitable for various coating solution environments¹⁸. To further enhance surface hardness and wear resistance while reducing friction, some high-end dosing rods are surface-plated with hard chrome; the plating thickness is generally maintained at around 25 μm¹⁵. In addition, there are metering rods with Teflon coatings to prevent particle buildup and streaking³.
Surface Structure
The surface structure of a metering rod directly determines its coating performance and is primarily divided into two types: smooth rods and grooved rods. Smooth rods have a smooth surface without grooves and are primarily used for hydrodynamic metering; their diameter and surface finish are key factors affecting the applied coating volume 9. Grooved rods, on the other hand, feature a surface machined with continuous wavy grooves or wrapped with steel wire, and are used for volumetric metering. The shape, depth, and width of the grooves directly determine the wet film thickness of the coating and are core elements in controlling coating precision 14.