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OPERATING INSTRUCTIONS
Roll Adjustments
(continued)
A trough is formed by the doctor roll and coating roll. This trough is where
the coating material will sit within the
“coating head assembly” with the ends
sealed by UHMW seal plates. These seal plates should be hand tightened by
either the hex nut or thumb screw located with the seal plate assembly. Only
tighten these seal plates when the machine is due to operate; before the
machine is turned on and the coating material is filled into the trough. When the
machine is not in use, loosen the seal plates ensuring that they are not touching
the rolls. The seal plates are a wear item and overtime will begin to leak. When
this occurs you will need to replace with new seal plates.
Before attempting to fill the trough, feeler gauges should be used between
the rolls at each end to ensure an even coat. In theory, to set a staring gap
between these rolls, the solids in the coating material and the desired dry film
thickness should be known. With these two factors, a setting for the gap
between the rolls can be determined by multiplying the dry finish thickness by the
percentage of solids, divided into 100. For example, the desired dry film
thickness is 0.002" and the solids in the coating material is 50% or 100/50 = 2.
Then 0.002" x 2 = 0.004 which is the gap required. Or, if the dry film thickness
required is 0.002" and the solids in the coating material is 20% then 100/20 = 5
