A metering rod, also known as a coating rod, scraper, line rod, or Mayer rod, is a precision measuring tool used in coating processes. It is widely applied in coating production and laboratory testing across various fields, including paper, film, tape, and optical materials. This tool enables precise control of the coating solution’s thickness on the substrate surface, achieving micron-level coating accuracy, and is an indispensable core component in the coating process.
Metering rods are typically made of stainless steel and undergo precision machining and surface treatment. Depending on the manufacturing process, they are primarily classified into two types: wire-wound and extruded. Wire-wound metering bars form grooves by winding steel wires of varying diameters; they feature a simple structure and lower cost.
Extruded metering bars, on the other hand, utilize a cold extrusion process to directly form continuous corrugated grooves on a stainless steel rod, offering advantages such as no risk of wire breakage, ease of cleaning, and high precision. Their operating principles encompass volumetric metering and hydrodynamic metering, capable of meeting diverse coating requirements ranging from laboratory R&D to industrial mass production.