By Nick Mike, NGM Tissue Consulting, LLC
Getting an optimum yankee coating has always been tricky. In the past, non-uniform CD variables such as spray boom alignment, yankee temperature and hood CD variation, hot yankee edges, moisture streaks, worn suction pressure rolls and creping doctor misalignment have always been obstacles to getting a good organic coating.
Today new tools for yankee dryer coatings allows the papermaker to fine tune the coating program. Developed by Tom Wright at GP Chemicals, a multi-component system utilizing multiple coating modifiers makes development of an almost perfect coating possible.
These "control levers" were first used in the complex coatings of structured sheet mills and has recently progressed to conventional tissue machines. These levers are coating components that:
1. Increase dry tack.
2. Increase wet tack.
3. Increase coating softness or durability.
4. Increase or decrease release.
5. Add or remove coating bulk.
6. Baseload phosphate. Typically leave steady and untouched.
By setting up the DCS system to simplify this component system, the operators can learn how to utilize these tools to fine tune the coating program or to make changes based on any set of variables commonly fiber source changes, older/newer felts, or wet strength addition. Taken to another level, these settings can be stored by grade and automatically entered without operator input. This next step in automating a previously manual, subjective, coating decision is the wave of the future. Resistance lies in past operator experience with only a coating and release control...two knobs. But by working with the crews to utilize these 5 yankee coating modifications from the DCS soon becomes second nature. Just think 10 years from now, crews will wonder how they ever made tissue with only two controls.
Nick Mike of NGM Tissue Consulting, LLC can be reached by calling 603-616-8931, or by email at nmike03580@yahoo.com.
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