The pulp and paper industry today manufactures a wide variety of paper products. The commercial printing industry consumes tons of paper daily for books - both hardbound and paperback - advertising promotion pieces, manuals, and catalogs. There is also an area of business requiring multiple forms with interleaved carbons, such as sales books, order forms, and records essential to the continuous daily conduct of business and industry. One of the largest users of paper is the newspaper and magazine publishers. For the publisher, paper is the greatest item of expense, representing more than the total cost of the printing, ink, and binding. New, faster presses the demand for strong, smooth, lightweight, trouble-free papers that achieve the best production of color printing, in illustrations ranging from museum art to food illustrations. Publications stock must have the strength for constant round-the-clock press runs to assure meeting news-breaking and news-making deadlines.
Engineering processes that produced paper and paperboard has been applied for packaging and for shipping containers which also comprises the largest tonnage sector of the paper industry. Shipping containers, also called fiber boxes, require millions of tons of paper and paperboard annually. Paperboard cartons of all types are used to package most of the prepared foods, soap products, cosmetics, and similar products that are used in daily life. In the United States, many thousands of different paper products are consumed at the rate of hundreds of pounds per person a year.
Chemical engineers find these materials very useful. Paper and paperboard are used to package items as light as needles or as heavy as refrigerators, as fragile as eggs or as massive as motors. Infinitely thin or indestructibly strong, water repellant or water resistant, tissue soft or tough, disposable or permanent - paper and paperboard have an essential daily role in the shipping, wrapping, marketing, delivery, and selling of products that make up every phase of the daily economy of the United States. More than half of the production of U.S. pulp and paper is in the South. Many of the larger mills produce pulp as well as paper, and some also produce finished paper products.
The production of paper depends on many factors, namely the materials used, the grade of pulp refinement, the type of machine used to make the paper, and the finishing treatment after the paper is formed. The process of manufacturing paper begins in the woodlands where trees designated as pulpwood are cut into prescribed lengths, measured in cords, and hauled from the forests to the wood yards of the pulp company. Pulp is also taken from the waste products of wood working: oak, pine, aspen, beech, to name a few. The long fibers of soft wood give paper strength. Hard woods produce short fibers that give paper a smooth and shiny surface. Different paper products use different combinations of pulp. For instance, most newspapers are a blend of chemical pulp and ground pulp. The glossy paper of magazines is coated with a solution of starch and clay. This type of surface is very good for printing. In high quality papers, such as stationary, money, and art products, linen and cotton are added to enhance the paper’s strength and durability.
Mechanical engineer jobs have been done also at the wood yards. The cords of lumber are placed on conveyor belts and fed into a giant, revolving drum barker, which strips away the bark and cleans the wood. Moving along on conveyor belts, this strips away the bark and cleans the wood. The chipper - a revolving disk with heavy, sharp knives set at an angle - quickly reduces the logs to millions of wood chips about an inch square and an eight of an inch thick. The wood, in chip form, travels on conveyors to the digesters, which are like a giant pressure cooker. Chemicals and steam are added and combine to break down the chips into soggy masses of cellulose and other elements of the tree. The chemicals are now removed, along with the lignin, resins, and natural chemicals found in the tree, leaving the cellulose fibers to be further processed.
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