Basis weight, CD varying
Carefully check headbox variables and slice setup. 1. Eliminate headbox shower water pressure pulsations that can disturb both MD and CD profiles. 2. Adjust headbox variables to obtain optimum flow pattern. 3. Check condition of slice screws and adjust slice. 4. Check for a warped slice or a dirty slice lip. 5. Check for poor […]
Water flow to headbox, excess
1. Consistency of the stock in the headbox is of utmost importance. When water flow is either greater than that which gives the critical velocity in the headbox (avoiding flocculation), or is greater than that which can be drained effectively, then it is excessive. 2. If the slice is not properly adjusted, formation will be […]
Basis weight (CD) variations
1. An off-machine basis weight profiler is the minimum tool that should be considered today. (a) use profiler with composite and superimposed profiles. — determine stability of variations shown as this indicates degree of correction that may be achieved. (b) adjust the slice. — always adjust using manufacturer’s restrictions on deviations between screws to avoid […]