Metering Rod / Mayer Bar Coater

 

The Metering Rod coater is still widely used today due to its simple operation and low cost in comparison to other coaters available.

 

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Fig 1. Metering Rod / Mayer Bar Coater

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It employs the use of a pan fed kiss applicator roll which transfers an excess amount of coating to the web followed by either a smooth metering rod or wire wound mayer bar (wire wound rod) to smooth or meter the coating. Coating weight variations are made by either varying the web tension over the smooth rod or by employing wire wound rods with varying wire diameters, a larger wire diameter giving a higher coating weight. Coat weights can also be controlled by varying the angle of wrap on the applicator roll and metering rod.

These types of coater rod coater are predominantly used as a pre coater or back wet coater for boards because the nature of its operation allows it to give the board maker an extremely smooth base on which to apply the secondary or top coating.

 

Strengths

• Simple design

• Easy to operate

• Adapts easily to existing equipment

• Wire size used to control wet film thickness

• Will handle a wide range of coated products

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Weaknesses

• Tension sensitive for coat weight

• Speed sensitive

• Little coat weight control except via changing wire size or rod diameters.

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Click here for Board Coating document

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Typical Machine Photos 
(Click to Enlarge)