Collective term for the loading, beating, and refining of paper pulp fibers to produce the desired characteristics of the papermaking furnish. The degree of refining, beating, and the addition of specific types and quantities of fillers and sizing all affect the paper that ultimately emerges at the end of the papermaking process. Stock preparation is performed after the papermill receives the pulp from the pulpmill, either in wet or dry form. The cellulose fibers comprising the pulp must be in a water suspension both for loading and to control the fiber bonding as the paper web forms.
Stock preparation systems can either be batch or continuous. Batch systems swirl the pulp in a beater followed by a conical refiner. The purpose of beating is to swell and soften the fibers which faciliates the later binding of the fibers to form the paper web. Continuous systems utilize disk refiners that facilitate abrupt changes, depending on what the ultimate end-use of the paper is destined to be.
Differences in the nature and extent of refining and of the type and quantity of fillers and additives directly affect the paper that is produced, as refining is the determining factor in how the cellulose fibers bind with each other. (See Paper and Papermaking: Papermaking.)