There are two main types of pencils - simple and colored. A simple pencil has a graphite lead and writes, depending on the hardness of graphite, in gray - from light to almost black. Simple pencils differ in the hardness of the lead, which is indicated by the letters M (or B in the English version) - soft and T (or H) - hard. Normal - a hard-soft pencil is marked with the letters TM or NI (sometimes it is also indicated by the letter F). This marking is applied to the pencil body. If the pencil is not marked in any way, it means that it is hard-soft. Colored pencils also come in several forms: classic color (single and double sided), wax, pastel, watercolor, etc.
Despite the fact that graphite pencil is popularly called “simple”, the technology for its production is much more complicated than the technology for manufacturing colored pencils, since, unlike the latter, it requires additional firing.
Simple pencil lead is made of white clay - kaolin and graphite, and the core of colored pencils consists of kaolin with colored pigments. Moreover, the pigments themselves can be both synthetic and natural. The stylus, which includes natural components, is more convenient to use, provides a soft application, gives bright saturated colors that do not fade even under direct exposure to sunlight. Special emulsions are added to the stylus of watercolor pencils, which dissolve upon contact with water, creating a uniform layer of paint on paper - the so-called watercolor effect.
Pencil stick cores are made by pressing natural pigments and linseed oil. And the composition of the stylus of wax pencils as a binder includes, as the name implies, wax. It creates a solid stylus mount, leaves a wide oily mark and provides better glide on paper.
The manufacturing process of pencils in a woody shell is fully automated and consists of several stages: the manufacture of stylus, boards, joining components and processing blanks. First of all, from the mixture of clay and graphite, the lead is made of future pencils. The proportions of the components at the stage of mixing graphite and clay determine the hardness of the future lead. The more graphite is added to the lead, the softer its structure will be. If kaolin predominates in the lead, the pencil will be harder.
Clay is pre-cleaned. For this, the raw materials are first crushed in crushers, then mixed with warm water in special mills. Clay diluted in water is poured with liquid glass to get rid of extraneous impurities - sand, etc. Then graphite is added to the clay, according to the recipe, and a binder that is cooked from starch.
The rod mass must be of a certain temperature and humidity. The slightest deviation from the norm will lead to spoilage of raw materials. For example, when the mixture dries, it will become too hard, which can cause equipment breakdown. Carefully mixed “dough” made of graphite and clay gets into the screw press. There it is molded through rollers with three different gaps. As a result of this procedure, the mass is crushed, becomes homogeneous, air bubbles and excess moisture are removed from it. The thickness of the dough during each reprocessing gradually decreases - from 1 mm to 0.25 mm.
Then the mass is passed through a die with holes, after which it turns into the so-called "noodles". It is formed into cylinders, from which a rod of the required length and diameter is extruded on the press. The rods need to be dried. This is carried out in drying cabinets with continuous rotation for 15-16 hours. The humidity of the finished rod should not exceed 0.5%. After drying, the rods are calcined in special crucibles in the furnace. During the firing process, a binder is burned in the rod, and the sintered clay forms a stylus frame.
In addition to the clay ratio, the hardness of the finished pencil is also affected by the temperature and duration of firing, as well as the components that make up the so-called fattening bath. The stylus is fired, depending on the desired gradation, at a temperature of 800 to 1200 degrees Celsius. After firing, the rods are placed in a special bath for fatliquoring. As a result of this operation, the pores that formed in graphite after burning the binder are filled with fat, stearin or wax under pressure at a certain temperature.
Sometimes food and confectionery fats, as well as additional binders (for example, based on starch), can be used as raw materials. The choice of substance that is used for fatliquoring depends on the hardness of the rod. For example, for pencils with soft stylus, confectionery fat is used, and for hard ones, wax is used. Grease stearin is used for the manufacture of leads of intermediate hardness (for example, hard-soft). Large diameter rods are made on vertical masonry presses.
Cores for colored pencils are made in a slightly different way. They include pigments, fillers, binders and fatliquoring substances. Clay (kaolin) is the main raw material. Pigments, astringents and, in some cases, fatty additives are added to it. Each manufacturer has their own stylus for making lead, which is kept in great secret. Many factories use other additional additives, including dyes, natural fillers, wax, cellulose-based binders.
After mixing all the components, the mixture is extruded using a press, and at the output, rods of the desired diameter are obtained. They are cut into pieces of a given length, and then dried at room temperature. As we mentioned above, only graphite rods are quenched. Cores for colored pencils do not undergo heat treatment, since under the influence of high temperature color pigments are destroyed (if we are talking about components of natural origin) or significantly change color (this applies, first of all, to inorganic components).
At the stage of adding fat, which gives a colored trace and holds colored particles on paper, two different technologies can be used: the so-called cold or hot “preparation”. During cold preparations, fat is added to the mixture while mixing the components. As a rule, this technology is used in the production of inexpensive pencils of medium quality, the stylus of which consists of organic pigments, which, in turn, are contraindicated in high temperatures.
Hot preparation is carried out immediately after drying the rods. As a result of this procedure, the leads are wetted in hot fat. This method is used in the production of high-quality art (especially watercolor) pencils. The composition of such a bath is one of the main trade secrets of the factory, but, in any case, it contains high-quality organic fats (for example, coconut or sunflower oil).
All colored pencils are conventionally divided into school (high-quality, inexpensive and cheap) and art. The latter are of the highest quality and good coloring properties. But, in any case, regardless of the price category, the pens of both simple and colored pencils must go through several stages of quality control, unless, of course, the manufacturing company cares about its reputation.
Along with the production of rods, pencil cases are made. The pencil case is made from various tree species, which determines the quality of the finished product. For example, alder and poplar wood is considered to be of low quality. In order to achieve a satisfactory quality of the body, this material requires expensive processing, which can not afford small manufacturers who choose such wood. Linden wood is considered satisfactory in quality. It is used most often for the production of inexpensive school pencils. The wood of pine, jelutong and cedar (Siberian and California) is considered high-quality, expensive and is used for the production of special art pencils.
The manufacturing process of a wooden pencil case consists of several operations. First of all, finished wood blocks will be required. They stick along the length of future pencils with allowances for machining and shrinkage. Wooden blanks are sawn into separate boards on a multi-saw machine and soaked in paraffin in autoclaves to improve the mechanical properties of the finished product. The thickness of each board is half the thickness of the finished product. When steam is processed, resins are removed from the boards, and the wood acquires a light brown color with a pink tint.
After that, the boards are dried in the "wells", where they are folded using a machine. The laying method used allows to increase the area of the plank that comes in contact with hot steam. On the one hand, this optimizes the production process, and on the other, it allows maximum removal of moisture from raw materials. "Wells" are rearranged in drying rooms, where they are for 72 hours. Then the boards are taken out and sorted. During sorting, scrap is removed (cracked workpieces, improperly sawn boards, etc.). Impregnated with various compositions and dried boards are sorted and calibrated by size.
Grooves or grooves for the stylus are made on each plank, and then PVA glue is applied on it evenly. After that, the pencil is assembled: a stylus is inserted into one of the two boards, and then it is covered with a second board. At the same time, the core itself does not stick to the board, but is held by the interference of the “shell”.
Since the diameter of the rod is slightly larger than the diameter of the groove, the correct compression of the plank in a special device, the clamp, where the pencils are glued together, is of great importance. According to production technology, for pencils of a certain size and type, a pressure indicator is used for pressing. Deviation from the recommended indicators leads to a lot of marriage: pencils simply break under the press.
The resulting blocks go to the milling-throughput line, where they are divided into pencils with knives. The type of knife determines the shape of the future pencil - faceted, oval or round. Then almost finished pencils are sent for sorting by conveyor belt. Sorters check each pencil to identify and seize defective products.
The blanks obtained as a result of crimping are sawn along the length of the pencil, leveled, ground, primed and covered with paint and varnish. The surface of the pencil is opened with paint and varnish by the method of broaching (extrusion), and its ends - by dipping. In the first case, the pencil is passed through a primer. First, it moves in one direction while applying varnish or paint, and then at the other end of the conveyor turns over and returns. This helps create a uniform and even coating.
Pencils of dark colors are covered with paint in at least five layers, and varnish - in four. In light colors, the pencil is painted in at least seven layers of paint and four varnishes. But ideally, so that the surface of the pencil is smooth, without smudges and “burrs”, the total number of layers of varnish should be at least seven to eight (the more layers, the more expensive the finished product). The maximum number of layers is 18.
To color the ends of the pencils, the so-called dipping machine is used. With its help, the frame with pencils is gently lowered into the paint tank. But in some cases, paint and varnish are not required. For example, cedar pencils go on sale without additional wood processing. It is believed that the texture of the tree itself is quite beautiful and does not require painting and varnishing. The designation of the lead hardness is applied to the pencil by shock hot stamping using colored foil tape.
Pencils go on sale in two forms - sharpened and not sharpened. The products of the first type are packed into boxes exclusively by hand, and the second - manually and using special automatic and semi-automatic equipment. On a semi-automatic machine, you can pack about 15 thousand pencils per shift, on a machine - more than ten times more. Machines pack boxes of six or twelve pencils in each. The productivity of equipment for packing pencils is, on average, 350-550 packs per hour.
So, the quality and, consequently, the cost of the finished product are affected by the exact observance of the technological process in the production of the stylus and body and during assembly. The core of the pencil should be located exactly in the center of the body. If the alignment of the stylus is broken, then when sharpening it will be cut unevenly and drawing with such a pencil will be impossible.
The type of wood used is also important for sharpening a pencil. Material of poor quality crumbles, and the wood of linden, pine or cedar gives a smooth, neat chip when sharpening the product. Of great importance is the high-quality double gluing of the stylus. It protects the rod from deformation inside the case. Such a pencil is not afraid of falling even from a great height. The “eight-layer rule” provides not only the aesthetic appearance of an alder, linden or poplar product, but also protects against splintering. And, of course, of particular importance is the safety of the material used in the production - from wood to paint and varnish. In particular, only safe water-based varnish is used for the manufacture of pencils.
The total cost of the necessary equipment for the production of simple and colored pencils starts from 2.5 million rubles. This will cost the cheapest used line (most likely, incomplete). Add to this the cost of renting industrial premises (at least 50 square meters for small production), paying utility bills, and wages to employees.
To work on the production of pencils, the following specialists will be needed: a calibrator of boards, sharpener of pencils, rods and sticks, a picker of pencils and rods, a dyer of pencils, a machine operator of a printing machine, an operator of an automatic line for the manufacture of white pencils, a roaster of graphite rods, an operator of automatic machines for assembling pencils, a rolling line operator, the operator of dispersion mixers for the preparation of the core mass, the finishing of pencils on the machine, the press of pencil blocks, the press of the rod minutes, impregnators pencil planks impregnators rods razmolschik pencil mass raskatchik rods cutter bars yarns smesitelschik sorter in the manufacture of pencils, dryer rods shihtovschik, grinder rods shtempelevschik pencils. Of course, the exact number and types of specialists that will be required to work in a factory depend on the size of production, the assortment, the technologies used and the budget.
Finished products are sold, as a rule, through wholesale companies. The batch of pencils produced is too large, so working with retail chains directly to manufacturers is impractical.
The exact payback period for the pencil business is difficult to name. First of all, they depend on the volume of production and the initial starting capital. In addition, during the first time, all profits will most likely be invested in promoting their products on the market, since competition among manufacturers of simple and colored pencils is very high (especially among Western manufacturers, with which domestic factories cannot yet compete in the quality of their production). their products). The minimum payback period according to some reports is from 2-3 years (for a small enterprise).
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