Will the lead break or not? Today we will try to understand the technological process of production of pencils and find out what will happen to the stylus?
Although it is called simple, it is quite a technological product. For the manufacture of one pencil is spent over 80 manufacturing operations within 11 days. The quality and price of the final product largely depend on what material and how it is made.
Briefly, the process of making a pencil is as follows.
- Getting a bar
- The bar is sawn into planks
- The boards are impregnated with wax (paraffin)
- Indentations are made in the boards
- The stylus is placed in the recesses
- Another board is placed on top.
- Pencil compartment
- Coloring a pencil
- The pencil has a metal rim
- An elastic band is inserted into the metal rim
Wood for the manufacture of the shell of pencils must have a number of specific properties:
- be light, soft and durable, do not break or crumble in the process of making pencils;
- have the same resistance to cutting fibers both along and across, should not delaminate;
- the cut when cutting with a sharp knife should be smooth, shiny, the chips should curl, not chip or break;
- wood should be low hygroscopic, i.e. must not absorb moisture.
All these qualities correspond to the virgin juniper, which grows in the USA. The wood of cedar and linden is the closest in its properties and structure, but for use in pencil production, it must first be subjected to a special treatment - waxing (i.e., ennoblement). The boards are sawn into bars, the bars are cut along the length to the length of a pencil with allowances for machining and shrinkage, and then the bars are sawn into planks on a multi-saw machine. After that, the boards are impregnated with paraffin - this procedure improves the mechanical and chinking properties of the future pencil. All resins are removed from the boards for a couple, and the legnin of wood, when interacting with steam, changes its color to pinkish-brownish. Then the boards are thoroughly dried. After drying, they are sorted - cracked boards are rejected, boards sawn on the wrong fiber, etc. "Refined" with paraffin and dried boards are sorted and calibrated - "grooves" (grooves) for the rods are applied to them.
graphite rod made from a mixture of clay and graphite. Clay is pre-cleaned. To do this, it is crushed in special crushers, then mixed with warm water in special mills. Clay diluted in water during processing is poured with liquid glass, which, settling, removes all impurities from it - pebbles, twigs, sand, etc. Further, according to a special recipe, graphite is added to the clay, and each gradation has its own recipe. The mixture is mixed with a binder aparatin, cooked from starch. For the manufacture of rods, a rod mass of a certain temperature and humidity is required. In no case should the mixture be allowed to dry out, otherwise it will be like a stone.
Kneaded clay and graphite dough by screw press pressed for molding through special equipment - rollers with three different gaps. This is done for grinding and grinding the mass, averaging the humidity by volume and removing air bubbles. The thickness of the dough layer is first 1 mm, when reprocessed 0.5 mm, then 0.25 mm. Then the dough is passed through a die with holes, forming the so-called "noodles". The “noodles” are formed into cylinders, and from them a rod of the required diameter and length is pressed through a diamond die on a press. The rods are finally dried in special drying cabinets - continuously rotating for 16 hours. After this process, the moisture content of the rod is approximately 0.5%.
Then rods are calcined in a furnace. Firing is necessary in order to burn out in the rod binder and bake clay to form a frame. The degree of hardness (gradation) of a pencil from 6M to 7T depends on the ratio of clay, the temperature and duration of firing, and the composition of the fatliquoring bath. Depending on the gradation of the rod, firing is carried out at a temperature of 800 to 1200 degrees.
After firing is carried out fattening operation: the pores formed after the binder is burned out are filled with fat, wax or stearin under pressure at a certain temperature. The choice of substance for fatliquoring depends on the gradation (hardness) of the rod. For soft pencils confectionery fat is used, for hard ones - wax. Intermediate values of hardness, for example TM, are achieved by greasing with stearin. Leads for colored pencils are made from a mixture of pigments, fillers, fattening agents and a binder.
Next comes assembly process. The rods are placed in the grooves of the prepared plank and covered with a second plank. The boards are glued together with PVA glue, but the rod itself is not glued to the board, but is held due to the tightness of the board. The diameter of the rod is slightly larger than the diameter of the groove, so it is very important to properly compress the boards in a special mechanism, where future pencils are glued together. Each pencil size has its own pressure rating for pressing in, so as not to break the core.
In addition to p prevent lead from breaking In the event of a pencil drop, many manufacturers use the so-called SV lead sizing technology. If the pencil is dropped, the lead can only break at the sharpened tip, not inside the body.
Further the ends of the glued boards are processed- Trimmed, removed the remnants of glue. On the milling line, the blocks are divided into pencils. The shape of the future pencil depends on the shape of the knives - it will turn out round, faceted or oval. "Newborn" pencils are sent on a conveyor belt for sorting.
Finishing pencil surfaces is carried out by extrusion (broaching), and the end face is finished by dipping. Extrusion is the process of passing a pencil through a primer. At the end of the conveyor, the pencil is turned over so that the application of the next layer of paint or varnish occurs from the other end. This results in an even coverage.
It is well known that less than 7 layers when painting with pencils is not allowed, otherwise the tree will become covered with burrs. Companies that are more serious about the quality of their products usually start with 12 layers. Very expensive products are stained up to 18 times, sometimes up to 20. Then the pencil acquires an unsurpassed glossiness and a downright mirror surface. However, many believe that more than 18 layers is already an excess. Application dark colors made 5 times with paint and 4 times with varnish, light - 7 times with paint and 4 times with varnish. Pencils are sharpened automatically, and all pencils are marked at the factory. The packaging of sharpened pencils is made by hand, in one full shift You can pack about 15 thousand pencils.
So, if the pencil was glued using a special SV technology, then be calm, it will not break.
Pencils They differ mainly in the type and nature of the writing rod (which determine the writing properties of the pencil and its purpose), as well as in size, cross-sectional shape, color and type of wooden shell coating.
Since the 1950s, pencils have been produced in the USSR in accordance with GOST 6602-51. The quality was good. The current situation is rather sad. Let's talk about what happened before.
Pencils
Depending on the writing rod and its properties, the following main groups of pencils are distinguished: a) graphite - the writing rod is made of graphite and clay and impregnated with fats and waxes; when writing, they leave a line of gray-black color of varying intensity, depending mainly on the degree of hardness of the rod; b) colored - the writing rod is made of pigments and dyes, fillers, binders and sometimes fats; c) copiers - the writing rod is made from a mixture of water-soluble dyes and a binder with graphite or mineral fillers; when writing, they leave a gray or colored line, difficult to cut with an elastic band.
Stages of production of pencils from glued boards
Production of pencils consists of the following main processes: a) the manufacture of the writing core, b) the manufacture of the wood shell and c) the finishing of the finished pencil (coloring, marking, sorting and packaging). The composition of graphite rods includes: graphite, clay and adhesives. Graphite is very graded and leaves a gray or grey-black streak on paper. Clay is mixed into graphite to bond its particles, and adhesives are added to the graphite-clay mixture to impart plasticity. Screened graphite in vibratory mills is crushed to the smallest particles. Clay is soaked in water. Then these components are thoroughly mixed in special mixers, pressed and dried. The dried mass is mixed with adhesives, repeatedly pressed, turning into a homogeneous plastic mass suitable for molding writing rods. This mass is placed in a powerful press, which squeezes out thin elastic threads from the round holes of the matrix. Upon exiting the matrix, the threads are automatically cut into segments of the required length, which are the writing rods. The segments are then placed in rotating drums, where they are rolled out, straightened and dried. After drying, they are loaded into crucibles and fired in electric furnaces. As a result of drying and firing, the rods acquire hardness and strength. The cooled rods are sorted by straightness and sent for impregnation. This operation aims to give the rods, which after firing increased rigidity, softness and elasticity, i.e., the properties necessary for writing. For the impregnation of graphite rods, tallow, stearin, paraffin and various types of wax are used. For the manufacture of color and copy rods, other types of raw materials are used, technological process partially changed.
For colored rods, water-insoluble dyes and pigments are used as colorants, talc is used as fillers, and pectin glue and starch are used as binders. The mass, consisting of dyes, fillers and binders, is mixed in mixers, the firing operation falls out. The strength of the colored rod is given by the pressing mode and the regulation of the amount of binders introduced into the mass, and this, in turn, depends on the nature and amount of pigments and dyes. For copy rods, water-soluble aniline dyes are used as dyes, mainly methyl violet, which gives a trait when moistened. purple, methylene blue, giving a line of greenish-blue color, brilliant green - bright green, etc.
The strength of the copy rods is regulated by the recipe, the amount of binder and the pressing mode. Finished rods are placed in a wood shell; wood should be soft, have low cutting resistance along and across the grain, have a smooth, shiny cut surface and even tone and color. best material for the shell is the wood of the Siberian cedar and linden. Wooden boards are treated with ammonia vapor (to remove resinous substances), soaked in paraffin and stained. Then, on a special machine, “paths” are made on the boards, into which the rods are placed, the boards are glued and divided into individual pencils, while giving them a hexagonal or round shape. After that, the pencils are ground, primed and painted. Coloring is done with fast-drying nitrocellulose paints and varnishes, which have a clean tone and bright color. After repeated coating of the shell with these varnishes, a strong varnish film is formed on it, giving the finished pencil a glossy, shiny surface and a beautiful appearance.
Classification of pencils
Depending on the source materials of the writing rod and the purpose, they differ following groups and types of pencils.
1. Graphite: School, Stationery, Drawing, Drawing;
2. Color: School, Stationery, Drawing, Drawing;
3. Photocopiers: stationery
In addition, pencils differ in overall dimensions, in the hardness of the core, and in the finish of the shell. Dimensional indicators include: cross-sectional shape, length and thickness of the pencil. According to the shape of the cross section, pencils are round, faceted and oval. Some groups or types of pencils are assigned only one cross-sectional shape; for others, different ones are allowed. So, drawing pencils are produced only faceted - hexagonal, copying pencils - only round; stationery can have any of the indicated shapes, as well as a three-, four-, octahedral or oval cross-sectional shape. The pencils are 178, 160, 140 and 113 mm long (with a tolerance of ±2 mm for these dimensions). The main and most commonly used of these sizes is 178 mm, it is mandatory for graphite pencils - school, drawing and drawing; for color - drawing and drawing; for stationery colored pencils, a length of 220 mm is also allowed. The thickness of a pencil is determined by its diameter, and for faceted pencils, the diameter is measured along the inscribed circle; it ranges from 4.1 to 11 mm, the most common thickness is 7.9 and 7.1 mm.
According to the degree of hardness writing rod pencils are divided into 15 groups, designated by letters and numerical indices in sequential order: 6M, 5M, 4M, 3M, 2M, M, TM, ST, T, 2T, ZT, 4T, 5T, 6T, 7T. The letter "M" denotes the softness of the writing rod, the letter "T" - its hardness; the larger the digital index, the stronger this property is for a given writing rod. On school graphite pencils, the degree of hardness is indicated by the numbers No. 1 (soft), No. 2 (medium) and No. 3 (hard). On carbon pencils - in words: soft, medium hard, hard.
Abroad, the degree of hardness is indicated with Latin letters"B" (soft) and "H" (hard).
Graphite school pencils were produced in medium hardness, drawing pencils - of all existing degrees of hardness, colored pencils of all types - usually soft.
Graphite drawing pencils "Designer"
The wood shell coating color is also different for different pencils; the shell of colored pencils, as a rule, was painted according to the color of the writing rod; for the shell of other pencils, each title was usually assigned one or more permanent colorings. The color of the shell was of several types: one-color or marbled, decorative, with ribs or edges painted in contrasting colors or covered with metal foil, etc. Some types of pencils were produced with a decorative head, which was painted in colors different from the color of the shell , with a plastic or metal head, etc. Pencils with plastic or metal tips, with an elastic band (only graphite), with a sharpening of the rod, etc. were also produced.
Depending on these indicators (properties of the writing rod, cross-sectional shape, overall dimensions, type of finish and design), different names were assigned to each type of pencils and sets.
Graphite drawing pencils "Polytechnic"
Assortment of pencils
Pencils are divided into three main groups: graphite, colored, copying; in addition, there is a special group of special pencils.
Graphite pencils by purpose are divided into school, stationery, drawing and drawing.
School pencils - for schoolwork in writing and drawing; three degrees of hardness were produced - soft, medium and hard - designated respectively by numbers: No. 1, No. 2, No. 3.
Pencil No. 1 - soft - gave a line of thick black and was used for school drawing.
Pencil No. 2 - medium hardness - gave a clear black line; used for writing and drawing.
Pencil No. 3 - hard - gave a pale line of grayish-black color: it was intended for drawing and initial work on drawing at school.
School pencils included pencils that had a metal nipple in which a rubber band was fixed to erase notes made with a pencil.
Stationery pencils - for writing; produced mainly soft and medium hardness.
Drawing pencils- for graphic works ; produced according to the degree of hardness of the writing rod from 6M to 7T. Hardness determined the purpose of the pencils. So, 6M, 5M and 4M are very soft; ZM and 2M - soft; M, TM, ST, T - medium hardness; ST and 4T - very hard; 5T, 6T and 7T - very hard, for special graphic works.
Drawing pencils - for drawing, shading sketches and other graphic works: available only soft, different degrees of hardness.
Assortment of graphite pencils
colored pencils according to purpose are divided into school, stationery, drawing, drawing.
School pencils - for elementary child drawing and drawing works of schoolchildren lower grades
; were produced in round shape, in sets of 6-12 colors.
Stationery pencils - for signature, proofreading, etc., 5 colors were produced, sometimes two-color - for example, red-blue, mainly hexagonal, except for Svetlana pencils, which had a round shape.
Drawing pencils - for drawing and topographic work; produced mainly in sets of 6 or 10 colors; hexagon shape; coating color - according to the color of the rod.
Drawing pencils - for graphic works; several types were produced, differing from school ones in length and in the number of flowers in sets, from 12 to 48, mostly round, except for drawing No. 1 and No. 2, which had a hexagonal shape. All sets had 6 primary colors, additional shades of these colors and usually pencils white color.
All pencils produced in sets were packaged in artistically designed cardboard boxes with multi-colored labels.
Assortment of colored pencils
Copying pencils two types were produced: graphite, that is, containing graphite as a filler, and colored, the writing rod of which contained talc instead of graphite. Copying pencils were produced in three degrees of hardness: soft, medium hard and hard. Copying pencils were produced, as a rule, in a round shape.
Assortment of copying pencils
Specialty pencils - pencils with special properties of the writing rod or special purpose; produced graphite and non-ferrous. The group of special graphite pencils included "Carpenter", "Retouch" and briefcase pencils (for notebooks).
Carpenter's pencil was intended for marks on a tree when performing carpentry and joinery work. It had an oval-shaped shell and sometimes a rectangular section of the writing rod.
Pencil "Retouch"- for retouching photos, shading, applying shadows. The writing rod contained finely ground birch charcoal, as a result of which it gave a thick line of thick black color.
Four numbers were produced, differing in hardness: No. 1 - very soft, No. 2 - soft, No. 3 - medium hardness, No. 4 - hard.
Special colored pencils included "Glassographer" and "Traffic light".
Pencil "Glassographer" had a soft core, giving a fat and thick line; used for marks on glass, metal, porcelain, celluloid, for laboratory classes etc. Produced in 6 colors: red, blue, green, yellow, brown and black.
Pencil "Traffic light" was a type of colored pencils, had a longitudinally composite rod, consisting of two or three colors, which made it possible, when writing with one pencil, to receive a line of several colors. Pencils were designated by numbers corresponding to the number of colors that the rod wrote with.
Names and main indicators of special pencils
Pencil quality
The quality of the pencils was determined by the conformity of the core, shell, finish and packaging to the requirements set by the standard. The most important indicator of the quality of pencils were: for graphite - fracture strength, hardness, intensity of the line and slip; for color - the same indicators and (color compliance with approved standards; for copiers - the same is the copying ability of the rod. All these indicators were checked with special instruments and in laboratory conditions. In practice, to determine the quality of pencils, the following requirements should be followed. The writing rod should have be glued into a wooden shell firmly and as accurately as possible in its center; the non-centricity of the rod was determined by the smallest, i.e., the thinnest part of the shell, the dimensions of which were established by the standard for pencils of the 1st and 2nd grades; the writing rod should not come out freely from the shell when sharpening a pencil or when pressing on it from the end; should be whole and uniform along its entire length, should not contain foreign impurities and inclusions that scratch the paper when writing, should not have any obvious or hidden cracks, should not was supposed to crumble when sharpening and writing.When sharpening a pencil, with a vertical pressing on the sharpened tip of the rod, the latter should not give chips, i.e., arbitrary breaking off or chipping of the rod particles. The cross-sectional area of the rod at the ends of the pencil had to be even, smooth, without damage and chips. For colored rods, a line of the same color and intensity was required when writing along the entire length of the rod.
The shell of the pencils was made of good quality wood, without knots, cracks and other defects; should have low cutting resistance, i.e., it should be easily and softly repaired with a sharply sharpened knife, not break during sharpening and have a smooth cut surface. The ends of the pencils had to be cut evenly, smoothly and strictly perpendicular to the axis of the pencil. The pencil should be straight and even along its entire length, without deformation. The surface had to be smooth, shiny, without scratches, dents, cracks and varnish runs. The varnish coating should not crack, crumble and stick when wet.
By defects appearance pencils were divided into two grades: 1st and 2nd; moreover, the writing properties for pencils of both varieties should have been the same. The 2nd grade included pencils in which the deflection along the length was not more than 0.8 mm, the chipping of wood or varnish film from the end of the pencil was not more than 1.5 mm, the chipping of the rod at the ends was not more than half the cross-sectional area of the rod - to a depth not more than 1.0 mm, the non-centricity of the rod is not more than 0.33 D—d (D is the diameter of the pencil shell along the inscribed circle, d is the diameter of the rod in mm), as well as scratches, dents, roughness and sagging (width and depth not more than 0.4 mm) no more than 3 over the entire surface of the pencil, with a total length of up to 6 mm and a width of up to 2 mm.
Pencils were marked with bronze or aluminum foil on one or more faces. The marking had to contain the name of the manufacturer, the name of the pencils, the degree of hardness (usually in letters) and the year of issue (usually the last two digits of the corresponding year (for example, “55” means the release of 1955). On copying pencils, the marking contained the abbreviated word “Copy” On pencils of the 2nd grade, in addition, there should have been the designation “2 s.” The marking had to stick firmly to the surface of the pencil, be clear, legible, all lines and signs should be solid and not merge.
Pencils: Ruslan, Rogdai, Ratmir (factory named after Krasin)
Pencils are packaged in carton boxes mainly 50 and 100 pieces of the same name and variety. Colored pencils for school and drawing were packed in sets of different colors of 6, 12, 18, 24, 36 and 48 colors in one set. Graphite drawing pencils, colored drawing pencils and some other types of pencils were also produced in sets of different contents. Boxes with pencils of 50 and 100 pieces and sets of all kinds were issued with a multi-color art label sticker. Boxes with sets and pencils of 10 and 25 pieces were placed in cardboard cases or packed in packs of thick wrapping paper and tied with twine or braid. Boxes with pencils of 50 and 100 pieces were tied with twine or braid or pasted over with a paper parcel. Boxes with sets of colored pencils were pasted over with multi-color labels, usually with art reproductions.
Pencils "Cosmetics" (Slavic State Pencil Factory MMP Ukrainian SSR)
Graphite pencils "Painting", "Youth", "Colored"
Set of colored pencils "Youth" - art. 139 out of 6 pencils. The price is 77 kopecks.
Set of colored pencils "Color" - art. 127 and 128 from 6 and 12 pencils. The price of one pencil is 8 kopecks and 17 kopecks, respectively.
Set of colored pencils "Painting" - art. 135 out of 18 pencils. The price is 80 kopecks.
Colored graphite pencils "Painting", "Art"
Set of colored pencils "Painting" - art. 133 out of 6 pencils. The price is 23 kopecks.
Set of colored pencils "Art" - art. 113 out of 18 pencils. The price is 69 kopecks.
Set of colored pencils "Art" - art. 116 out of 24 pencils. The price is 1 ruble 20 kopecks.
Udalov Dmitry
Research work. The history of the pencil. Graphite. Which pencil is best?
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IV city scientific readings
them. I.V. Kurchatova
Thread: What is a pencil made of?
Udalov Dmitry
Student 4 "B" class
MOU "Secondary School No. 21"
Scientific adviser:
Baradacheva I.G.
teacher of the highest category
MOU "Secondary School No. 21"
Ozersk
2010
Introduction …………………………………………………………………3
1. Theoretical part
1.1. The history of the appearance of the pencil…………………………………..……5
1.2. Taiginsk graphite deposit in the Urals…………..….… .…6 1.3. Pencil manufacturing technology……………………..…….….7
2. Practical part…………………………………………………..8
Conclusion ………………………………………………………….… ..10
Literature ……………………………………………………………….11
Applications …………………………………………………………… 12
Introduction.
Doesn't look like a human
But he has a heart
And work all year round
He gives his heart.
He writes when they dictate
He draws and draws.
And tonight
He will color the album for me. ( Pencil)
It would seem that just not invented for writing or drawing!Goose and metal pens, ink and ink, ball pen, marker. But all the same, in the backpack of a first-grader, in the artist and draftsman, accountant and carpenter, and on the table of the chairman of the board of the bank, there will always be a few simple pencils. A truly universal thing - writes always and everywhere: upside down, and in the cold, and under water, and in space. The pencil does not need advertising. Fair. A pencil is like bread. They don't notice it when it's there. And when it is not there... In the first days of the Patriotic War, the pencil factory in Moscow began to produce military, it would seem, more necessary products - ammunition. And pencils disappeared from the city. There was an instruction from the government not to stop pencil production for a single day. The need for pencils has not decreased in our time. Statistics say that a person needs at least 10 pieces a year.
It's interesting that:
one ordinary wooden pencil you can draw a line 56 km long or write more than 40 thousand words;
the world's largest pencil 12 meters long, weighing 24 centners;
most small pencil in the world a little less than two centimeters;
more than 14 billion pencils are produced in the world every year - from this amount, you can circumnavigate our planet 62 times.
from one big tree can make approximately 300,000 pencils.
We were interested to find out which pencils are preferred by the students of our school, how they are used, whether they know what pencils are made of. For this purpose, a survey was conducted among students in grades 4, 8 and 11 of the MOU "Secondary School No. 21". (See Appendix #1) The students answered a series of questions regarding their use of pencils. The results are presented in the form of diagrams (see Appendix No. 2). We were surprised that not all students know what a pencil is made of. 3 people (10%) were able to answer this question correctly in the 4th grade, 11 people (50%) in the 8th grade, 18 people (90%) in the 11th grade. Based on the lack of awareness of students in this matter, we decided to carry out this work.
Objective: find out what the pencil is made of.
Tasks:
study special literature (find out the history of the appearance of a pencil, the technology of its manufacture; learn about the deposits of graphite in the Chelyabinsk region, the method of extraction and processing of graphite, its main properties);
carry out practical work (observation of the extraction of graphite, questioning students, competition for the best pencil);
compare the results;
identify the most popular pencil among students.
Object of study:simple pencil.
Practical significancethis material can be used in the lesson of the surrounding world on the topic "Minerals of the Urals", fine arts on the topic "History of the creation of a pencil", class hour“On the careful use of the forest”, etc.
Research methods:
1) descriptive;
2) experimental;
3) quantitative;
4) comparative.
The pencil is such a common item. The first writing instrument that adults have entrusted to us. It is simple and not at all mysterious. Indeed?
How old is he, for example? And has the question ever occupied you: how do they stuff a lead into it? And what happened when there was no pencil? With this, perhaps, we will begin.
1.1 History of the pencil.
Who and when gave the world this amazing object?
The history of the pencil begins in the 14th century.The principle itself - a solid substance that leaves a dark mark on cardboard, parchment or paper - has been known for a very long time. As writing material used metals: silver - for richer people, lead - for those who could not boast of prosperity. It was with such writing instruments that such masters of graphics as Dürer, Van Dyck and Botticelli made their sketches.
Prototypes of modern graphite pencils appeared in the 16th century. Then for the first time graphite was used for writing.
A graphite deposit was first discovered in England, and quite by accident: shepherds from the Cumberland area discovered a dark mass in the ground, which they used to mark sheep. The trace from these rods was clearer and brighter than from lead rods of a similar purpose, which were widely used for writing and drawing in those years. Graphite is a black shiny soft mineral composed of carbon. To the touch graphite greasy and gets dirty. On surfaces, it easily gives a silver to black streak. This is a mineral, as if by nature intended for writing. And its name comes from the Greek "grafo" - I write. This material was soon noticed by artists and businessmen, who quickly established trade in thin plates and pieces of graphite on the English streets, began to make thin sticks pointed at the end from it and use them for drawing. Graphite began to be used everywhere and so massively that the deposits began to dry up rapidly. By order of the royal court, graphite could only be mined for a few weeks a year so as not to deplete its reserves. And in late XVIII centuryEnglish Parliamentintroduced a strict ban on the export of precious graphite. For violation of this prohibition, the punishment was very severe, up todeath penalty.
Of course, it was very inconvenient to use graphite - hands got dirty! It was necessary to wrap graphite with rope, paper, or even simply clamp it between the planks.
The idea to put graphite, which easily leaves a mark on paper and does not stain hands, in a case belongs to the French inventor and businessman Nicolas Jacques Comte (1775). Conte invented the technology for making a graphite rod from a mixture of powdered graphite, soot, clay and water. After stirring, the mixture was poured into a wooden mold and the water was evaporated. The pencils were made by hand. Therefore the cost graphite pencils was considerable. Only the court nobility could afford such pencils.
The first pencils were round. It's hard to imagine today, but inventors have spent decades trying to solve the problem of a pencil rolling off a table. Only in late XIX century Count Lothar von FabercastleI guessed to make the body of the pencil hexagonal -for a more stable position on inclined writing surfaces. He is also the author of the standard length and diameter of the pencil.
The great Russian scientist Mikhail Lomonosov also entered his page in the history of the pencil. Indeed, in Russia there is both graphite and wood - and in one of the villages of the Arkhangelsk province a manufactory appeared, producing graphite pencils in a wooden shell.
1.2 Taiginskoye graphite deposit in the Urals.
Many graphite deposits have been discovered in Russia. In the Urals, graphite deposits are located on the outskirts of the city of Zlatoust and 12-14 km south of the city of Kyshtym - the Taiginskoye deposit. (see Appendix No. 3)
In 1939, a geological exploration party of the Ural Geological Administration headed by geologist Z.I. Kravtsova arrived in Kyshtym, which explored the area of the city of Kyshtym and in 1940 established reserves of crystalline graphite ore near Lake Taiga, 15 km from the city of Kyshtym (see .Appendix No. 4). The beginning of the Great Patriotic War set the task of the fastest development of deposits of crystalline graphite. Crystalline graphite is batteries used in combat aircraft, ships, and tanks. This is armored steel, heavy-duty refractory alloys, this is the raw material for the development of communications: receivers, transmitters, telephones. The Council of People's Commissars ordered the People's Commissariat of the USSR Building Materials Industry to immediately start building the Taiginsky graphite plant. In September 1941, on the shores of Lake Taigi in rainy conditions, cold autumn and the harsh winter unfolded construction. The builders, who lived in tents, semi-dugouts, temporary barracks, cleared the industrial site, led the power line, built the building of the processing plant, boiler room, canteen, utility shops, laid railway line delivered and installed equipment. Simultaneously with the construction of the plant, the technology for producing graphite was being developed. In May 1942, ore mining began, and on June 27, 1942, an aircraft landed on Lake Temnoye, the crew of which took on board the first batch of graphite, a gift from Kyshtym graphite workers to the army and navy. During the Great Patriotic War, the plant was the only enterprise that gave the country thousands of tons of valuable products.
For more than 60 years, the Uralgrafit enterprise (see Appendix No. 5) has been producing natural graphite for enterprises in various industries:
For metallurgy - the production of crucibles, non-stick paints;
For mechanical engineering - electrodes, lubricants, heat-insulating material, batteries;
For the production of nuclear technology;
For the production of pencils.
The need for graphite is due to its special physical properties: fire resistance, acid resistance, high electrical conductivity, softness and ductility.
Graphite mining and processing technology is as follows: graphite is mined open way in careers. It is loaded by excavators and delivered to the factory by Belaz dump trucks. (see Appendix No. 6). Graphite enters the mill, where it goes through three stages of crushing. Next, the graphite is washed from impurities, in which graphite floats to the surface, and impurities sink to the bottom. Graphite collected from the surface is dried, ground, classified and packed in paper bags.
Released from Taiginsky graphite a large number of pencils.
Currently, due to the economic crisis and strong competition with foreign firms, Uralgraphite is curtailing its production. (See Appendix No. 7)
1.3 Technology for the manufacture of pencils.
Though penciland is called simple, but it is quite a technological product. More than 80 production operations are carried out to produce one pencil.
The core is the main working part of the pencil. In the production of pencils, dry graphite powder is mixed with clay and water. The more clay, the harder the pencil, the more graphite, the softer the lead. Depending on the amount of clay, pencil rods have different degrees of hardness - T (hard), M (soft), TM (hard-soft). After forming a pasty paste from the mixture, it is passed through a molding press, obtaining thin sticky ropes. They are straightened, cut to size, dried and sent to the kiln for firing. Finished rods are sent to the pencil factory.
In the production of simple pencils, it is important to choose the right wood. The cheapest material is alder, followed by linden, tropical or European pine, thin-ribbed diera, growing only in tropical forests .. The most good pencils are made from California cedar, we use Siberian cedar wood.
The process of making pencils begins with the production of a pencil board (see Appendix No. 8). To improve the properties of wood, pencil boards are subjected to thermal treatment followed by impregnation with paraffin. In the manufacture of pencils on pencil boards, semicircular grooves are milled for the rods. Processed boards are stacked in a foot.
The assembly of pencils is carried out on gluing equipment. The rods are placed in the groove of the boards, they are covered with other boards, with a layer of glue applied to them. The resulting blocks are clamped and held certain time in a thermal chamber. Then the ends of the blocks are polished on the machine, removing the protruding ends of the rods and the unevenness of the glued pairs of planks. After grinding, the blocks have a rectangular shape and smooth ends. The final part of the pencil production process is the milling of pencils of a given shape (round, faceted) with a special cutting tool. So, the pencil is ready.
At least seven layers of paint must be applied to the body of the pencil, otherwise “burrs” will form on its surface. Howpencilmore expensive, the more layers of paint it is covered with. The ideal coating is considered to be a coating consisting of 18 layers.
AT this moment significant requirements are imposed on the production of pencils in terms of their environmental safety. It is recommended to use water-based varnishes.
Today, more than 300 types of pencils are produced for various activities. There are pencils for writing on glass, fabric, cellophane, plastic and film. There are pencils used in construction that leave a mark on the surface that is on outdoors for several years.
Currently, there are a large number of companies producing pencils in the world. What do you think, how many enterprises in Russia are engaged in the production of pencils? Only four. Two of them are in Moscow. The other two are in Tomsk and Slavyansk.
2. Practical part.
According to the results of the survey among students in grades 4, 8 and 11 of the MOU "Secondary School No. 21", the following pencils were preferred (see Appendix No. 9):
1st place - "Designer" Russia (12 people)
"Koh-i-Noor" Czech Republic (12 people)
2nd place - " Nixon Austria (7 people)
3rd place - "EVOLUTION" France (6 people)
80% of students noted in the questionnaires (see Appendix No. 2) that these pencils are comfortable and write well.
These pencils became participants in the "Super Pencil" contest, which was held in my 4th "B" class. The students were divided into 4 expert groups who made observations and measurements. Each group had one test sample. Three contestants are made of wood ("Constructor", "Koh-i-Noor", "Nixon") and one plastic ("EVOLUTION”), with a plastic shell and lead. For the purity of the experiment, the contestants (pencils) were wrapped in paper and numbered. (see Appendix No. 10). All pencils had the same hardness (TM), standard sizes. The research groups were provided with the same accessories: a ruler, a sharpener, an eraser (see Appendix No. 10). The examination was carried out in two directions - the material and the stylus were evaluated.
Material
The quality of the wood from which the body of the pencil is made affects how it will look finished goods and how easy the pencils will sharpen. It is very important for a pencil: what kind of wood looks like, what color, how well the stylus holds. The quality of the wood ensures even, neat chips.
The material was evaluated:
1.Color
2. Density.
3. Shavings
stylus
Compliance with production technologies also affects the strength of the rod and its consumer characteristics. The stylus must have a high degree strength, should not crumble and should be easily erased with an eraser. Also, during production, the technology of mixing the mixture for the lead should be especially carefully observed, its heterogeneity and the content of impurities can lead to scratching the paper when working with a pencil.
The stylus was checked:
1. Centering
2. Crumbles when writing or not.
3. How to erase with an eraser.
4. Scratches paper when writing or not.
5. Profitability (lead consumption for 5 minutes of work).
6. Brittleness.
During the competition, observations and experimental tests were carried out, the results of which are listed in the table (see Appendix No. 11).
1st place - pencil number 4 "EVOLUTION" France
2nd place - pencil number 3 "Koh-i-Noor" Czech Republic
And a pencil at number number 2 " Nixon Austria
3rd place - pencil number 1 "Designer" Russia
The winner was the "EVOLUTION" pencil. As we remember, it was a plastic pencil. In fact,plastic pencils are very popular at the moment. The main advantages of plastic pencils are their low cost and absolute safety in case of breakage. Unlike wooden counterparts, they are not able to form sharp edges at the place of breaking.
Let's compare the obtained results (see Appendix No. 12). There was a discrepancy between the survey of students and the results of the competition. What is the reason? The quickest choiceschoolchildren and their parents with wooden pencilsdue to their environmental safety. Even an adult sometimes catches himself in an indecent lesson - he sits and chews on a pencil. And what about children!50% of the students surveyed have a habit of taking (nibbling) a pencil in their mouths (see Appendix No. 2).
However, there may be other reasons as well. In the questionnaires, 20% of the students noted that they chose a pencil, considering that it was cheap, beautiful, it turned out to be by accident (see Appendix No. 2). This means that it is necessary to study the economic side of the issue (the cost of pencils), their design (color, quality of painting), etc. Perhaps this will be the topic of my further research.
Conclusion
After completing the work, we found out what the pencil is made of. A pencil is a writing instrument made from wooden stick with a rod made of a mixture of clay mass with graphite (S. Ozhegov “Explanatory Dictionary of the Russian Language”).
The tasks set by us are fulfilled: having studied the special literature, we learned the history of the appearance of the pencil, the technology of its manufacture; got acquainted with the graphite deposit in the Urals, the method of extraction and processing of graphite, its main properties; carried out practical work (observation of the extraction of graphite, questioning of students, competition for the best pencil).
This material can be used in the lesson of the surrounding world on the topic "Minerals of the Urals", fine arts on the topic "History of the creation of a pencil", class hour "On the careful use of the forest", etc.
Literature
Sharpen your pencils and draw, draw, write. Why and why? - 2005, No. 12
Kulikova R. Ivashka in a wooden shirt. Reader - 2008, No. 9
How old is the pencil? And why? 2004, No. 7
Ilyin M., Segal E. Stories about what surrounds you. book. 2 Where things come from. M., 1985
Dietrich A. Why. M., 1993
Kukushkin Yu.N. Chemistry around us M., 1992.
Sources
en.wikipedia.org- free encyclopedia, article "Pencil"
evolutsia.com- "The history of the pencil"
shkolazhizni.ru- the article "What did our ancestors write, draw, draw with?
Application No. 1
Questionnaire of the student ... .. class.
You have a simple pencil in your pencil case. He:
1.- regular
Auto
Round
Hexagonal
With an elastic band
No elastic
2. Why did you choose this particular pencil?
Beautiful
Comfortable
writes well
Cheap
Turned out to be by chance
3. What brand is your pencil? (title)
4. What do you most often use a pencil for?
I draw
I emphasize
Church
5. Do you take a pencil in your mouth? Are you chewing on it?
Yes
Not
6. Do you write all the way through your pencil?
Yes
Not
7. Why yes?
Comfortable
writes well
getting used to
Why not"?
It is not convenient to write with a small pencil
I'm losing
I throw it away, cheap, it's not a pity
8. Do you know what a pencil is made of?
Not
Yes
9. If you know, name what is used in its production.
Application No. 2
Application No. 3
Application No. 4
Application No. 5
Application No. 6
What is a pencil lead made of?
- graphite(carbon mineral, natural graphite contains 1012% impurities of clays and iron oxides, for the production of pencils it is purified);
- silt(used as a binder, is a fixative);
- soot- to give black color and softness of the rod;
- water and starch- for the formation of a homogeneous mass, which goes to further formation;
- used for colored pencils pigments, as a filler: kaolin and chalk.
What is the filling of the pencil made of, and what will happen if you eat it - these are two, a little different questions. I roughly know the answer to the first one, as for the second, I am not strong in medicine.
They say that the lead of a pencil is graphite.
And graphite is carbon, that is Chemical substance, which is indicated in the periodic table as Cquot ;.
With certain manipulations, you can change the crystal lattice of graphite and get a diamond, since diamonds are also carbon, only apparently with a stronger crystal lattice.
Have not tried the lead. If someone has a fever from eating it, then perhaps this is from poisoning, because, as you know, graphite is not edible.
Those who are strong in Chemistry can analyze what reactions of Carbon can take place with acids that are present in the stomach. The substances resulting from such reactions can be harmful to the body.
The pencil lead is made from graphite, a natural hydrocarbon. Hydrocarbon is black and metallic in color. Natural dyes are used to create colored leads. The structure of graphite is porous and leaves a good mark on paper. the question is debatable. Since graphite contains particles of clay, they can probably provoke intestinal motility disorders, and hence an increase in temperature. But how much do you need to eat it, and why?
The lead consists of graphite, coal. The temperature may rise if you eat a lot of it, because of which it can cause poisoning and, as a result, an increase in temperature of about 38 degrees. Everywhere they argue, who says that this is a myth, someone says that it helps, perhaps everything is individual. It is better to raise the temperature in other ways, for example, if there is a cat at home, and cats always have a temperature above 37, you just have to measure it rectally. Or stir hot tea with a thermometer.
pencil lead consists of the following constituent parts:
The dried blanks are fired at a temperature of 1000 degrees.
Finished leads (after dehydration and firing) are dipped in a mixture of fats and wax to prevent brittleness.
Regarding raising the temperature after eating a lead from a pencil - It's a school joke. Allegedly, you need to eat a pencil lead pounded into powder - then the temperature will rise and you can not go to school.
However, if you eat a lot of leads, you can get poisoned, and this can raise the temperature. In addition, you can damage the mucous membranes with the sharp edges of the stylus - infection may occur, the temperature will rise.
It is better not to eat the stylus. Even in homeopathic doses ostensibly to combat heartburn.
But the stylus can be successfully used for lubrication door hinges or zippers. It is necessary to rub with a lead (or powder) the places where the door hinges creak. Or rub along the entire zipper - it will open better. This is equivalent to using graphite grease.
A pencil is such a common thing that it seems unremarkable and a simple tool for drawing. However, in order to make it, a rather complicated production technology is used. I want to talk about this little-known process.
The stages of pencil production can be divided into two parts: the manufacture of the lead and the manufacture of the wooden shell into which it is inserted.
The pencil lead is made from a mixture of graphite powders and special clay. Graphite powder itself is made from slate. A mixture of graphite and clay is thoroughly mixed with water, then dried, then again ground into powder, and at the end a small amount of water is added again until a thick paste is formed. The ratio of graphite and clay in this paste will determine the hardness of the pencil. The more clay, the harder the pencil will be. But the degree of hardness will still depend on another process, which I will describe below.
Then, this paste goes to special equipment, similar to an extruder. Graphite paste is pressed through the shaping holes of the stamp and at the exit you can see the familiar pencil core. However, he is still far from the finished rod.
The resulting lead blank is dried. Then they are fired at high temperatures in a special furnace. During firing, graphite and clay are combined, and the core hardens. As I wrote above, the hardness of the pencil will largely depend on this process. The higher the firing temperature, the harder the pencil will be. The less clay in the lead and the lower the firing temperature, the softer the pencil will be. As you know, hardness is indicated on pencils either in English letters or in Russian. The English "H" means "hard" and the English "B" means "soft". Accordingly, the Russian letter "T" means hard, and the Russian letter "M" means "soft". There is also a different degree of hardness of the pencil. For example, 2B or 2M is double soft, and 2H or 2T is double hard. In total, there are about 17 degrees of pencil hardness: from 8M to 8T.
After firing graphite rods fit into special wooden blanks for future pencils. These blanks are wooden plates, half a pencil thick. They are usually made from cedar or linden. This wood is soft and has fibers well suited for making pencils. From each such blank board, either 6 or 8 pencils are obtained, depending on the production standard. Accordingly, 6 - 8 grooves are sawn in these planks, for graphite pencil rods.
Next, the rods are placed in the sawn grooves. Then, a wooden plate with rods is covered with exactly the same plate from above. The graphite rods are placed between two wooden plates. The rods are securely fixed in a wooden shell in two ways: either by means of glue or by squeezing the wooden halves of the future pencil. The halves themselves in both cases are connected by means of glue and a press.
At the next stage of production, these blanks are fed to a special machine, the cutters of which have teeth in the form of halves of a hexagon, or halves of a circle. With such cutters, a wooden blank with rods is sawn, and at the same time a hexagonal or round shape is given to the resulting pencils.
Well, now the pencil is almost ready! But it hasn't been painted yet. Painting is done with special enamels. And when the pencil is already colored, a marking is made on it indicating the manufacturer, the degree of softness of the pencil, etc. Such embossing is done using paint or foil.
This is how it is - the difficult process of making a seemingly simple pencil.
