The Production Process for Weyerhaeuser Containerboard and Corrugated Packaging Producing Satisfaction from Renewable Resources slidelib\cbp\process (1)

Recycled Fiber Consumers and recycling businesses collect, sort and bale used corrugated packaging and office waste The recycled fiber bales are mixed with water and broken down to pulp in the hydrapulper and put through several cleaning and screening processes to ensure pulp quality The recycled fiber pulp supplements the virgin pulp in varying degrees, depending on the product performance required. Weyerhaeuser containerboard products contain recycled content ranging from 13 to 100 percent slidelib\cbp\process (12)

Papermaking The paper machine may be up to two blocks long and may run at speeds up to 60 miles per hour to create either liner or medium. At the machine’s “wet end,” the forming section lays a uniform mat of slushy pulp onto a wire mesh. Experienced operators use computers to carefully control fiber orientation, thickness and moisture content for various paper basis weights or products such as mottled white liner. The computers also monitor quality characteristics throughout production slidelib\cbp\process (13)

Papermaking (cont.) The press squeezes moisture from the pulp mat and compresses the fibers so they interlock to form a dense, smooth sheet Dryers remove more moisture from the containerboard sheet and further smooth it The winder rolls the containerboard (either liner or medium) into large, uniform rolls slidelib\cbp\process (14)

Roll Finishing and Shipping Rolls are cut to customer specifications, wrapped, bar coded and prepared for shipment via train, truck or ship slidelib\cbp\process (15)

Corrugating At the box plant, rollstock moves from its storage room to the “wet end” of the corrugator, where roll stands feed liner and medium into the corrugator in specific combinations The corrugator single-facer uses steam and rollers to flute the medium into its characteristic waves. Colored, non-skid or other coatings may be applied to the liner before it is glued to one side of the fluted medium slidelib\cbp\process (18)

Corrugating (cont.) The double-backer glues liner to the other side of the medium, forming rigid corrugated board. For some heavy-duty packaging applications, another set of corrugated medium and liner may be added to form double-wall board. Computerized process control helps skilled operators add options such as tear tapes and ensures warp-free board that meets specific customer specifications slidelib\cbp\process (19)

Corrugating (cont.) Hot plates remove excess moisture from the board and help set the starch-based glue At the “dry end” of the corrugator, a series of knives and notched rolls trim the board’s edges, slice it into appropriate widths, and add score lines for later folding. The board is cut into sheets that meet customers’ needs and stacked in preparation for finishing slidelib\cbp\process (20)

Finishing Corrugated sheets may require various finishing operations. The first stop is often a flexo-folder-gluer which prints, folds and often glues the board into knocked-down boxes. Careful process control and spot-checking ensure precision manufacturing Some packaging needs die cutting to create hand holds or air vents or to cut the sheet into a shape needed for the finished box design. Die-cutters may also feature printing sections slidelib\cbp\process (21)

Finishing (cont.) Customer needs may require other manufacturing steps such as wax coating for produce packaging or stapling for heavyweight packaging The finished packaging is bundled, stacked into units and banded or stretch wrapped for shipment slidelib\cbp\process (22)

Satisfied Customers Trucks transport the packaging to customers’ packing lines, where it helps protect, transport and sell products ranging from oranges to toilet paper to electronics slidelib\cbp\process (23)

Completing the Loop After goods are purchased by consumer, packaging is picked up curbside or taken to collection center where it is sorted along with office waste and other recyclables From here, recycled fiber bales are returned to the mills where they go through several cleaning and screening processes before being reused in the production of new paper products