How are paper made?
April 24, 2009 4:45AM
Starts with large rolls of paper board stock. Rolls can be various widths depending on cup making machine. Roll is fed thru machine where is is formed around a cylinder and glued along the edge.
Next the cylinder goes along the machine where a paper board bottom is inserted and also glued into place. The paper board stock can be either poly or wax coated to make it leakproof. The wax or poly coatings can be added as the cup is being formed, or it can be applied to the board stock before the cup is formed. If the cup is going to be printed the poly coating or wax coating is applied after the printing is done. Print is done on the roll stock before the cups are formed.
The manufacturing of the paper begins after the fibre from the trees or other sources is gathered. This starts with pulp making. Logs are first cleaned of impurities, then de-barked, and subsequently turned into wood chips. These wood chips are converted into wood pulp. Separating cellulose from the lignin components of the wood produces wood pulp. Pulping can be done through mechanical or chemical processes. In the mechanical method of pulping, wood is chopped or grinded. This is done to sift all the unneeded particles of the wood. The cellulose fibres will remain intact. </p Chemicals and steam is oftentimes added in the mechanical process. Mechanical pulping can efficiently turn about 90% of wood into usable pulp. The papers produced turn yellowish because lignin is not removed thoroughly with this process. This occurs when it is dried out in the sun. It produces a weak sort of paper. The chemical pulping method incorporates heat, pressure and chemicals to dissolve unwanted particles such as lignin. Wood is mixed with chemicals such as sodium sulfide and sodium hydroxide. It is cooked in large vats known as digesters. This produces pulp that will be filtered. Bleach is combined to the pulp in this part of the process. After the pulping stage is the beating stage. The pulp is pounded and squeezed by machine beaters. In the tub where the pulp is beaten, filler substances and sizings are added. These substances affect the look. It also affects the reaction to ink of the finished product. The paper will be too absorbent if sizings are not incorporated. The pulp is ready to be turned into paper once the beating stage is done. The pulp is placed or fed into huge automated machines. The machine has a moving belt inside with mesh screens. These screens are very fine in texture. The pulp is then squeezed and flattened by rollers. Water is drained out by the rollers through these mesh screens. Suction devices underneath the belt will remove the excess water. The next step is to have the paper pressed. A pressing machine does this. It consists of woollen rollers. The paper is then steam-heated by mechanical cylinders. It is used to get rid of the remaining excess water. The next process is when the paper reaches the finishing stage. The paper is rolled into reels. This would be processed to turn it to the finished product. The paper is compacted and evened out by metal rollers known as calendars. These calendars can make the paper's finish into various gradients and textures. Additional finishing touches such as receiving coatings and sizings can also be incorporated. The final production phase would be the cutting stage. The paper is sliced to different sizes. It will be grouped according to the kind of paper made.