Manufacture of machinery for paper and paperboard
Paper is a thin material mainly used for writing upon, printing upon or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets.
Paper is a versatile material with many uses. Whilst the most common is for writing and printing upon, it is also widely used as a packaging material, in many cleaning products, in a number of industrial
Within the packaging industry, the generic term is more often pasteboard, and specific kinds are referred to by their initials or a shorthand. The most common types used for retail packaging are SB (solid bleach), CCKB (clay-coated kraft back) and CCNB (clay-coated news back).
Pulp is a dry fibrous material prepared by chemically or mechanically separating fibres from wood, fibre crops or waste paper.
Pulp can be either fluffy or formed into thick sheets. The latter form is used if the pulp must be transported from the pulp mill to a paper mill. Pulp which is shipped and sold as pulp (not processed into paper in the same facility) is referred to as market pulp. When suspended in water the fibres disperse and become more pliable. This pulp suspension can be laid down on a screen to form a sheet of paper, and this is the primary use for wood pulp. Wood pulp is the most common material used to make paper. The timber resources used to make wood pulp are referred to as pulpwood. Wood pulp comes from softwood trees such as spruce, pine, fir, larch and hemlock, and hardwoods such as eucalyptus, aspen and birch.
Fibres in wood pulp
The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch. Paper may be between 0.07 millimetres (0.0028 in) and 0.18 millimetres (0.0071 in) thick.
Paper is often characterized by weight. In the United States, the weight assigned to a paper is the weight of a ream, 500 sheets, of varying "basic sizes", before the paper is cut into the size it is sold to end customers. For example, a ream of 20 lb, 8.5 × 11 in (216 × 279 mm) paper weighs 5 pounds, because it has been cut from a larger sheet into four pieces. In the United States, printing paper is generally 20 lb, 24 lb, or 32 lb at most. Cover stock is generally 68 lb, and 110 lb or more is considered card stock.
The 8.5 × 11 in (215.9 × 279.4 mm) size stems from the original size of a vat that was used to make paper. At the time, paper was made from passing a fiber and water slurry through a screen at the bottom of a box. The box was 17 in (431.8 mm) deep and 44 in (1,117.6 mm) wide. That sheet, folded in half in the long direction, then twice in the opposite direction, made a sheet of paper that was exactly 8.5 × 11 in (215.9 × 279.4 mm).
In Europe, and other regions using the ISO 216 paper sizing system, the weight is expressed in grammes per square metre (g/m or usually just g) of the paper. Printing paper is generally between 60 g and 120 g. Anything heavier than 160 g is considered card. The weight of a ream therefore depends on the dimensions of the paper and its thickness.
The sizing system in Europe is based on common width to height ratios for different paper sizes. The largest standard size paper is A0 (A zero). Two sheets of A1, placed upright side by side fit exactly into one sheet of A0 laid on its side. Similarly, two sheets of A2 fit into one sheet of A1 and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets).
The density of paper ranges from 250 kg/m (16 lb/cu ft) for tissue paper to 1,500 kg/m (94 lb/cu ft) for some speciality paper. Printing paper is about 800 kg/m (50 lb/cu ft
Card and paper stock for
craft use comes in a wide variety of textures and colors.
Main articles:
Paper size and
Paper density
Paperboard is a thick
paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.25 mm/0.010 in or 10 points) than
paper. According to
ISO standards, paperboard is a paper with a basis weight (grammage) above 224 g/m², but there are exceptions. Paperboard can be single or multi-ply. Paperboard used for the manufacture of folding
cartons and rigid set-up boxes is often called
boxboard. Paperboards used for the manufacture of
corrugated fiberboard are called
containerboard. It can be easily cut and formed, is lightweight, and because it’s strong, it’s used in
packaging. Another end-use would be graphic printing, such as book and magazine covers or postcards. Sometimes it is referred to as
cardboard, which is a generic, lay term used to refer to any heavy
paper pulp based board.
Paperboard
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Manufacture of machinery for paper and paperboard
