Introduction Raw materials for the production of ceramic products are kaolins and clays. They are used in pure form, and more often - in a mixture with additives (leaning, pore-forming, fluxes, plasticizers). Kaolins and clays are understood as natural aqueous aluminosilicates with various impurities, which, when mixed with water, form a plastic dough, which, after firing, irreversibly turns into a stone-like state. The basis of any ceramic product is clay. By color, it is divided into two main types: red-burning, which turns red after firing, and white-burning, which turns white after firing. To determine what kind of clay you are dealing with, you need to make a test: burn a small piece of clay. Even some black clays turn white when fired.

Clay is one of the most common natural materials mastered by man in ancient times. The high plasticity of the material made it possible to make many household items from it - mainly dishes, jewelry and all kinds of cult figurines.

The earliest products were fragile, they were afraid of moisture, and only dry products could be stored in clay vessels. But, raking the ashes of an extinct fire, a person noticed more than once that the clay soil in the place where the fire was burning becomes hard as a stone. These observations, apparently, led a person to the idea of ​​firing clay products for strength.

Things made of fired clay are commonly called ceramics.

Modern ceramic production has sophisticated technical equipment, uses more advanced technology and new materials. But you can create ceramic products at home, using completely available materials and equipment, using a relatively simple technology.

Technology for the production of ceramic products

The manufacture of ceramic products includes several stages: the preparation of a dough-like mass, the molding of the product, the application of decor, drying, firing in a kiln.

1) Clay dough should be homogeneous in structure, without laminations and air bubbles, evenly mixed with additives, moistened to the required plasticity, able to take one form or another with little pressure. Conditioned clay does not stick to hands, its separate pieces are easily connected. There are several ways to prepare clay dough. One of them is as follows: dried and crushed clay is poured with a large amount of water, stirred to a fluid state, passed through a sieve into a clean container. The clay sinks to the bottom. The excess water is then removed by evaporation or by means of a pump. In summer, water evaporates easily in a wide container.

Before molding, the clay mass is subjected to additional processing: air bubbles are removed from it, kneading, giving it a uniform structure.

The quarried clay is usually mixed with sand, small stones, the remains of rotted plants and other foreign matter, which must be completely removed in order for the clay to become usable.

The cleaned clay is stored in a damp state in enclosed spaces until it is used. Exposure of clay for several months significantly improves its working qualities, allowing the clay to retain its shape in the process of creating a product, while remaining malleable and plastic. Fresh clay is often combined with old clay from a previous mixed lot; this enhances bacterial activity and improves the quality of the material.

2) The molding of ceramic products is carried out in various ways: plastic molding, casting (using plaster molds), pressing, hot injection molding.

The most commonly used methods of plastic molding are: manual - "by hand" (in the production of fine art products - flowers, jewelry, etc.); molding "stripes"; in plaster molds by modeling; in plaster molds using a template; on the potter's wheel.

The potter's wheel allows you to create symmetrical, evenly expanding or contracting vessels of various shapes. It consists of an iron vertical rod attached to the desktop and two wooden circles - a large, lower one (diameter - 95-105 cm), and a small, upper one (diameter - 30-40 cm). The potter's wheel is set in motion by the foot rotation of the lower circle. The upper circle is directly the workplace on which the product is molded. In this case, some tools are needed: a wooden cut, a piece of flat rubber, a walnut sponge, a metal club, pieces of leather and plexiglass.

Working on the potter's wheel requires virtuoso skill. Raw clay, thrown on the potter's wheel, is pulled into a cone with wet hands. By pressing on it from above with his hand, the potter lowers the mass down. This is repeated several times (to even out the texture of the clay mass). The elongated lump, as a result of pressing with the thumb, is turned into a hollow cylinder. Passing the walls of the cylinder between two fingers, the body and neck of the product are turned. With the help of a wooden cutter, the mass is given the necessary shape. During molding, the hands should be periodically moistened with water to increase the glide of the fingers. Having given the product a finished shape, it is smoothed down with a wet sponge and a piece of rubber, after which it is cut off from the potter's wheel with a thin wire or twine and set to dry - most often in the air. The product, dried up to 19-20% humidity, is placed in the center of the upper circle, attached with a piece of clay, and corrected with the appropriate tools; grind with a metal hook, smooth with a wet sponge, polish with plexiglass. If the product consists of several parts, they are glued together. Next comes the decoration.

Casting in plaster molds is based on the ability of plaster to absorb moisture. The liquefied clay mass, the so-called slip, is poured into a plaster mold, the moisture is absorbed and after a while an even layer of clay forms near the walls of the mold. The mass gradually hardens, the dimensions of the molded product are reduced and the resulting semi-finished product is easily separated from the mold. Such products are loose and give great shrinkage.

3) The next step in the production of ceramics is drying. A freshly molded or cast product contains from 22 to 30% moisture, depending on the molding method. The product must be dried to a moisture content of not more than 5% in order to avoid uneven shrinkage and cracking during firing. Raw material is dried in tunnel and chamber dryers.

The drying process at different composition mass passes differently: the fatter the clay, the longer it dries. With uneven density of the shard, shrinkage occurs unevenly, which leads to the appearance of cracks and deformation. The shape of the product also matters: the larger its area, the faster it dries. There should be no drafts during drying. First, the product undergoes preliminary drying, at 19% moisture content it is decorated, and then the final drying takes place.

The main purpose of drying a raw product is to reduce its moisture content, to acquire strength sufficient for transportation to a kiln and subsequent defect-free firing at minimal energy consumption. Flat products are usually dried in molds. Products made by casting are first dried in molds to give the products the necessary strength, and then they are removed from the molds and dried to a moisture content of 1 ... 2.5%. Conveyor dryers with directed hot air flows are used to dry bulk products. In these dryers, the drying process is combined with the operation of transporting products in the direction of the process flow. Separate art products are dried in chamber dryers periodical action where semi-finished products are dried on shelves or trolleys. For particularly complex products, natural drying is used on multi-tiered racks located at workplaces. The duration of artificial drying depends on the type of dryers used, drying methods and other factors and ranges from 0.25 to 3 hours.

4) Decoration. tricks artistic processing ceramic products are largely due to the characteristics of the material, the property of clay. These are painting manually, engraving, sgraffito, flyandrovka, “marble”, molding, polishing, reserving and others.

Painting is the most widely used method of artistic processing. They paint with engobe - finely ground liquid clay, white or with an admixture of dyes. Engobe drawing is applied only to a raw shard (19-20% humidity). It is impossible to paint an overdried product, since the engobe falls off during drying and firing.

For sculpting, ordinary sculptural stacks are needed - metal and wood. In addition, when working, a walnut sponge (soft rag, rubber sponge) is needed to remove the engobe.

Glazing is a widely used artistic and technical technique for processing ceramic products. Coating with glaze - vitreous mass - products pursues not only an aesthetic goal. Glaze protects it from moisture penetration, makes it more durable. Glazes can be transparent (colorless and colored) and opaque. Transparent colorless glazes well reveal the natural color of the clay from which the product is made.

The product after the first, scrap, firing is cleaned of dust with special brushes. The glaze prepared in the container is stirred to an emulsion state. The product is dipped in glaze or doused with it, then dried.

The basis of the glaze is quartz, feldspar, kaolin. Metal oxides are also introduced into the composition of the glaze, which achieves heat resistance and other qualities.

Glazes of restorative fire make ceramic products very beautiful: during firing, a metallic sheen forms on the surface. How is this achieved? At first, firing proceeds in the usual way, but at a kiln temperature of about 600 ° C, when the glaze on the shard is already motionless, air access to the kiln is blocked, reducing agents are introduced into the furnace in the form of a torch, oil, and rags. A reducing environment is created in the furnace, the fire removes oxygen and metal oxides. If you start reconditioning while the glaze is still in a liquid state, carbon can fuse into the glaze, causing it to become a matte, grey-black. If, however, a restorative fire is formed after the glaze has hardened, then restoration will not occur, the product will only be covered with soot. The recovery process lasts from two to six hours. Products are removed from the furnace only after they have cooled, otherwise the plating may stop. Glazes that give a metallic sheen to pottery are always fusible - they contain lead compounds that are easily reduced.

Ceramic goods- products made from clays, as well as their compounds with mineral and organic additives, fired to a stone-like state.

The word "ceramics" comes from the Greek word "keramikos" - pottery, derived from "keramos" - clay. Clay as a material for making household utensils was known to mankind in ancient times. The history of the production of ceramics using firing begins several millennia ago. Initially, the main type of ceramic products was dishes.

The spread of ceramics played a huge role in the history of mankind. The methods of processing raw materials, as well as the technique of manufacturing the ceramic products themselves, changed and improved in accordance with the development productive forces peoples. At present, ceramics has been widely used in all areas of life - in everyday life, in construction and architecture, in industrial technology. Ceramics includes various building and Decoration Materials: bricks and tiles, wall and floor tiles, tiles and water pipes, sanitary wares, insulators and other electrical fittings, the thinnest parts of textile machines, heavy refractory parts for casting tractor parts, all kinds of furnishings and personal items (dishes), large easel sculpture and bas-reliefs, monumental architectural facings in the form of picturesque and embossed panels tens of square meters in size, and much more. From modest products of everyday significance to world masterpieces of art - this is the area of ​​​​distribution of ceramics.

Ceramic products can be divided into two main groups − fine ceramics and rough ceramics.

Fine ceramics covers a group of products with a homogeneous structure of the crock, usually white or weakly and evenly colored. This includes all types of porcelain, faience and fine stone products.

To rough ceramics include products with an inhomogeneous, often coarser and more porous crock, which has a natural color (from dark brown to gray). This group of ceramics includes: bricks, tiles, architectural ceramics, pottery, etc.

Materials and production of ceramics

The main types of raw materials for ceramic products are plastic materials (clays, kaolins), floodplains (feldspar or pegmatite) and thinning materials (quartz or quartz sand, fireclay, ground ceramic shard).

plastic materials represent different kinds clays and kaolins, which have the property of plasticity, i.e., the ability, when mixed with water, to turn into a pasty mass, from which you can easily obtain the desired shape and save it. When fired, products made from clay or kaolin acquire the hardness of stone and, when mixed with water, no longer form a plastic mass. These two properties of clay materials explain their widespread use in the manufacture of various products.

To the floodplains include feldspar, pegmatite, chalk, limestone. These materials are used to lower the firing temperature and facilitate sintering during firing of the components of the ceramic mass. Melting is of particular importance in production porcelain, since it must have a sintered shard.

Skinny materials- quartz or quartz sand, broken skull, ground pottery. They are used to reduce the shrinkage of ceramic products, since uneven and strong shrinkage of products made from one clay during drying and firing causes deformation and cracking of these products.

Raw materials, going for the manufacture of ceramic products, is subjected to pre-treatment. Clay materials are cleaned from impurities by elutriation. Stony materials are also subjected to preliminary washing and grinding, then mixed with clay materials in special mixers. After mixing, the ceramic mass enters the filter presses to remove excess moisture, and then it is passed through vacuum mills or pug mills to obtain a more homogeneous mass and remove air bubbles. From the mass prepared in this way, ceramic products are made. Production is carried out by one of three main methods: plastic molding, casting, and much less often (simpler forms) pressing from a semi-dry mass in the form of a press powder. Pressing is carried out using metal molds and mechanical presses (tiles, electrical and radio engineering ceramic products).

Plastic molding and casting ceramic products are produced both manually and semi-automatically and automatically.

The method of plastic molding produces simpler forms - bodies of revolution (cylindrical, spherical), both hollow and flat, in plaster (rotating) forms using a template that fits exactly to the shape. The ceramic mass for molding should have approximately 25% moisture.

Casting is used for the manufacture of products of complex configuration (sanitary ware, sculpture, polyhedral and oval shapes) and thin ceramic products, such as thin-walled porcelain, laboratory ceramic ware, etc. Casting of ceramic products is based on the property of gypsum, which is ideal for making molds, absorb moisture. Ceramic mass for casting (so-called slip) should be thinner than molding and should have approximately 34-35% moisture.

The methods of plastic molding and casting are widely used in all types of ceramic production, both fine and coarse ceramics.

Firing of ceramic products is carried out in special furnaces. Furnaces are of two types: periodic action - forges, and continuous action - tunnel. When firing products in furnaces, they are placed in refractory boxes (capsules), and when firing in tunnel kilns, the products are installed on refractory whatnots. The firing temperature of ceramic products is carried out in the range from 900 to 1400 °. Products of fine ceramics undergo 2-3 firings: the first scrap, the second poured and the third, if you turn on the muffle firing, which fixes paints on decorative, artistic and household products (). Waste firing makes the handle of products stronger and more durable, which facilitates the subsequent process of processing ceramic products - glazing.

The application of glaze to ceramic products is carried out by various methods, including the most common manual or mechanized dipping into a liquid glaze mass. Glaze can be colorless, transparent or colored with metal oxides, both transparent and opaque (silenced). The glaze applied to the products is fixed (fused) to the handle of the products during the second (poured) firing. Rough pottery with a thick shard that requires glazing is often glazed immediately after drying without preliminary (scrap) firing and only one firing (Ceramic Ware).

For different ceramic products, depending on the requirements that apply to finished products, there are various modes the first and second firings, for example, for "hard" porcelain, the first firing is carried out at a lower temperature - 900 °, and the second (poured) at a higher temperature - 1380 °. For “soft” porcelain and faience, on the contrary, the first (scrap) firing is carried out at a higher temperature, and the second (poured) firing is carried out at a lower temperature (Porcelain tableware and Earthenware tableware). After firing, ceramic products are sorted, ground and polished (the latter refers to fine ceramics - porcelain), and then decorated, if the purpose of the products requires it, and fired in muffle furnaces at a temperature of 600 to 800 °.

Ceramic products are decorated in three ways: overglaze paints, underglaze paints and engobes, colored glazes. Decorated mainly products for household, art and household and architectural and construction purposes. Coloring substances in ceramic paints are metal oxides mixed with low-melting fluxes (glasses), which, during muffle firing, fuse the dye (or the so-called) to the surface of the glazed ceramic product. In underglaze decoration (the palette of which is much poorer than overglaze), the flux is the glaze, which is applied to the items before the second firing.

Classification

Ceramic goods are classified according to two criteria: by structure and composition and by purpose. Depending on the ratio of the components of the raw material, the methods of its processing, the temperature and duration of firing, ceramic products differ in porosity, hardness, translucency, color of the shard, and the presence or absence of glazes.

Depending on these features, products are divided into six main groups.

(the highest class of ceramic products) has a white sintered, and in thin layers a translucent shard, which gives a shiny conchoidal hard fracture, is covered with a thin layer of glaze, does not let moisture through, and when struck along the edge, it emits a melodic high, long-lasting ringing.

Products from "stone mass", or the so-called stone goods, have a dense, almost without pores, in a fracture, a conchoidal opaque shard, usually gray or Brown, rarely white, sometimes specially colored, glazed, usually transparent, sometimes with crystals or matte.

Faience has a white porous, not translucent even in thin layers, which gives a dull fracture, the shard is covered with colorless glaze, when struck on the edge, it emits a low, deaf, quickly fading sound.

Majolica has a porous, rough colored, sometimes gray or white shard covered with colored glaze.

Terracotta- architectural and building ceramics, porous shard, colored, usually brownish-reddish or sandy in color, sometimes coarse coarse-grained and thin - fine-grained, without glaze.

Pottery have a porous, colored, usually reddish-brown rough shard covered with colored or colorless glaze (pottery).

By purpose, ceramic products can be divided into three main groups: products for household and decorative purposes, products for architectural and construction purposes and products for technical purposes.

Products for household and decorative purposes. This group includes: 1) all kinds of dishes - porcelain, faience, majolica, pottery (cookware), heat-resistant (this includes pots, baking dishes, frying pans, braziers made from a special heat-resistant ceramic mass) - Ceramic dishes, Porcelain dishes , Faience crockery, Majolica crockery. 2) table sculpture (porcelain, faience, majolica, terracotta), vases for various purposes, dishes, decorative wall bas-reliefs and other products used to decorate the interior - Artistic ceramics.

Products for architectural and construction purposes. This group of products includes ceramic facade slabs, both smooth and architectural in the form of capitals, cornices and architectural details, widely used in modern architecture; brick, tile and ceramic tiles, oven facing tiles, floor tiles (metlakh tiles), sanitary wares (bathtubs, sinks, toilet bowls, etc.), ceramic pipes, park ceramic sculpture, park ceramic vases, etc.

Products for technical purposes. This group of products includes: electrical ceramics (porcelain and porcelain-like insulating products used in various fields of electrical engineering, for example, insulating porcelain); electronic ceramics (porcelain-like insulating materials with a low dielectric loss factor and used in electric fields high frequency); it is made by stamping, pressing, broaching, casting, it has high mechanical strength and heat resistance; laboratory porcelain, ceramic products for the chemical industry, insulators.

Quality requirements, packaging, marking, transportation and storage of ceramic products in the USSR were determined by GOST and departmental specifications that existed for each type of ceramic product.

Lit .: Saltykov A. B., Russian ceramics of the XVIII-XIX centuries, 1952; Kubbe A. N., History of faience, 1923; TSB, XX volume; Commodity science of industrial goods, edited by Sergeev M. E. and Arkhangelsky N. A., M., 1955.

Introduction.

Man invented glass in ancient times. Until the 13th century Venice was considered the center of glass production, lead glass (crystal) began to be made in England in the 17th century. In Russia, glass production began to develop in the 9th-10th centuries. The work of M. V. Lomonosov on glass technology had a great influence on the development of glass production in Russia. In 1864, D. I. Mendeleev devoted his work “Glass Production” to the study of the properties of glasses. In Russia, glass factories are known for their products: Gusevsky Crystal Factory, Dyatkovo Glass Factory (Bryansk Region), etc.

The production of dishes and household items from clay materials has been known in Russia since the 10th century. Porcelain was invented over two thousand years ago in China.

According to the structure and properties of the shard, ceramic products are divided into porcelain, semi-porcelain, faience, majolica, and pottery.

Raw materials and production.

Main raw materials: quartz sand, sodium sulfate, soda, potash, chalk, lead oxides, cullet, etc.

Auxiliary materials: illuminators; bleaches; dyes (copper oxide, cobalt oxides, etc.); silencers give the glass an opaque or milky white color.

Types of silicate glasses:

Ordinary - (lime-sodium, lime-potassium);

Crystal - has increased brilliance, strong refraction, high transparency.

Lead crystal consists of oxides of silicon, potassium and lead. Barium crystal contains barium oxide.

Heat-resistant glass withstands sudden temperature changes, contains boron compounds (up to 12.5%), has high heat resistance, and is used for the manufacture of kitchen utensils.

Glasses of all types have a high chemical resistance to all chemicals (except hydrofluoric acid).

Glassware production.

When preparing raw materials, they make up a charge - a mixture of materials according to a specific recipe. The mixture enters the furnace and cooks for 10-15 hours at a temperature of 1200°C.

There are different ways of molding glass products: blowing, pressing, pressing blowing, etc.

In the process of manufacturing glass products, internal stresses arise in them during cooling, which can cause the destruction of products. To reduce stresses, glass products are annealed after being worked out (heated to 580°C and then slowly cooled). Sometimes products that are not thermally processed enough are destroyed as a result of sharp temperature fluctuations during storage in warehouses. Glass products are tempered. Tempering is carried out in 2 stages: first, the product is heated, and then quickly cooled according to a certain regime (depending on the composition of the glass and the shape of the product).

Decoration (decoration) of glass products.

Decoration on glass can be applied during the manufacturing process of the product (in a hot state) and on finished products (in a cold state).

1. Decoration in a hot state: (colored glass products, products with on color, cutting “Crackle”). When blowing, the glassblower places it in a jar of cold water, it is covered with a network of cracks. The product is placed in an oven, the cracks are melted, then the blowing of the glass product with reliefs is continued.

2. Decoration in cold state: mechanical way. Abrasive materials are applied to glass products with a matte tape, numbered grinding, diamond engraving.

Number grinding - simple matte or transparent drawings, they are numbered.

Diamond face - patterns formed by two-, three-sided slots (grooves) using an abrasive wheel. Crystal products are decorated with a diamond facet.

Chemical method - jewelry is applied by etching with hydrofluoric acid. There is simple, complex and deep artistic etching.

Jewelry is applied with paints (painting), gold (antennae - 1 mm., layering - up to 3 mm., ribbon - 4 - 10 mm.), decalmania (using decals), decoration with chandeliers (paints based on non-ferrous metal salts).

Raw materials and production of ceramic goods.

The main materials for producing ceramics are clay (white and red-burning), kaolins (white clay-like material), thinning materials (quartz sand), floodplains (reduce the sintering temperature of the ceramic mass).

The production of ceramics consists of the following operations:

preparation of mass and glaze,

product molding,

drying and pre-firing,

glazing,

decoration.

The firing of household porcelain is most often carried out in two stages:

The first firing of porcelain (900 - 1000 ° C) - gives the products some strength.

The second (1350 - 1450°C) creates all the properties characteristic of a porcelain product.

Distinctive features of porcelain and faience.

The density of porcelain products is greater than that of faience, since the shard of porcelain is sintered, and that of faience is porous.

A shard of porcelain in thin layers is translucent, a shard of faience is not translucent even in thin layers.

The shard of porcelain is white with a bluish tint, while faience is white with a yellowish, grayish tint.

When hitting the edge, porcelain products emit a long high-pitched sound, earthenware - a deaf and short one.

The hardness of porcelain glaze is 3.5 times higher than that of faience.

The heat resistance of porcelain glaze withstands extreme temperature fluctuations without cracking. The faience glaze has lower limits of heat resistance, there may be cracking of the glaze at high temperature. Porcelain glaze is more chemically resistant to alkalis and acids than earthenware glaze.

The edge or foot of porcelain is not glazed, faience products are completely glazed. Majolica products have relief decorations, often covered with one- or multi-color glaze. The shard of majolica is porous, in composition and properties it is close to faience.

Decoration of ceramic products.

Ceramic products are decorated with ceramic paints, chandeliers, preparations of gold and silver.

Ceramic paints are applied with a brush (painting) and in a semi-mechanized way (stencil, stamp). Antennae, layering, ribbon - stripes that are applied with gold or paint (antennae - 1 mm, layering - 1 - 3 mm., Ribbon - more than 3 mm.).

Painting - pictorial drawings differ from other cuts in the presence of traces (strokes) of the brush.

Covering - the product is covered with paint. The cover can be solid, semi-cover, descending, with cleaning. The cover is solid - the entire product is covered evenly with paint; semi-covering - the surface of the product is painted over with a strip wide up to 20 mm. and more. With a downward covering, a gradual transition is made from a continuous layer of paint to nothing. Cover with cleaning - in a continuous cover, unpainted areas of various shapes are left.

Printing is a graphic, mostly one-color drawing. The printed drawing is contour, consisting of small strokes, dashes.

Stencil - the pattern is applied using a spray gun through a stencil. When using one stencil, the pattern is one-color, several stencils are multi-color. Distinctive features of the stencil: parts of the pattern of the same color are separated from each other, the edges of the pattern are clearly defined.

A stamp is a one-color pattern repeated on a product. It is applied using a rubber stamp with paint or gold.

Decalcomania (decal) - a single-color or multi-color drawing, applied to the product using decals. It differs from the paintings by the absence of brush marks, and from the print by a one-color outline.

Silk-screen printing is widely used for jewelry. The paint is forced through mesh stencils. The drawings are bright, embossed, of varying complexity, strokes and dots are clearly visible.

Photoceramics - decoration in the form of portraits, landscapes, transferred to the product from photographic plates.

Additional types of finishing decorations:

Mottling - partial painting of a picture with paint or gold to emphasize details.

Arabesque - a narrow side ornament applied with paint or gold, by hand.

Highlights - embossed strokes of colorless paint to emphasize the light details of the picture.

Depending on the nature of the location on the products, the drawings are divided into a bouquet, spreading, side and solid. The bouquet consists of sculptures or drawings up to three inclusive. Scattered - from sculpting or drawings from five or more. Side - most often, an ornamental continuous decoration along the side of the product. All drawings are applied to the product both separately and in a different state. Drawings on ceramics are divided into groups depending on the complexity. Products made of porcelain and faience without cuttings are called “linen”.

Classification and assortment of glass products.

The range of glass products is subdivided according to the composition of the glass mass, production method, purpose, types, styles, sizes and decoration methods.

The size of plates, saucers is determined by the upper diameter, in mm., Glasses and other full products by capacity, in cm or in liters, tall products (vases) - by height in mm.

Dinnerware(sorted glass).

The range of tableware is divided by functional purpose:

products for eating and drinking; this group includes glasses, goblets, glasses, glasses, wine glasses, plates, cups, etc.

products for serving food and drinks - bowls, dishes, vases, decanters, salt shakers, sugar bowls, herring bowls, salad bowls, butter dishes, etc.

Menazhnitsy - dishes with sections (3 - 5) for serving several types of cold appetizers.

The second group includes utensils for short-term food storage: cheese caps, jugs, tea caddies, etc., as well as other items (trays, ashtrays, etc.), cutlery and sets.

Crystal products.

Produced by blowing and pressing. The range of crystal tableware includes items for table setting, vases, salad bowls, etc. Crystal items can be in a metal frame made of silver, cupronickel, nickel silver.

Household and kitchen utensils.

Household utensils include canning jars, thermoses, thermos flasks, household siphons, etc. Kitchen utensils intended for cooking are made of heat-resistant glass by pressing followed by hardening. The range of kitchen utensils includes pots, braziers, frying pans, etc.

Artistic products.

Produced from high quality glass and crystal. These include small sculptures, vases, decorative dishes, toiletries (a patch for toiletries, powder boxes, etc.).

Classification and range of ceramic products.

The range of ceramic products is divided into the following groups:

assortment of porcelain tableware (dining room, tea and coffee),

assortment of faience dishes (dining room and tea),

assortment of majolica dishes,

assortment of pottery

artistic and decorative items.

Dishes are subdivided by types, shape, styles, types of cuts, by the complexity of cuts, by size.

The dimensions of flat and round products are determined by the upper diameter (in mm.). Full products - by capacity (in cm or in l.). Oval - along the greater length of the oval (in mm.). By the height of the case (in mm.) The dimensions of high products are indicated.

By completeness, single and complete products (sets, headsets, services) are distinguished. Sets are produced in one style, cutting for 4, 6 or 12 people.

Quality indicators of glassware.

Glassware is subject to technical, functional, ergonomic and aesthetic requirements.

Technical requirements for the quality of glass, production, processing, dimensions must comply with the requirements of regulatory and technical documentation (NTD).

The surface of the products must be smooth, foreign inclusions and other external glass defects are not allowed.

The product, placed on a flat surface, should not swing, cutting, sharp edges are not allowed. Lids should fit freely into the product, without noticeable swing. When checking the quality of products, the quality of processing and decorations is taken into account, the dimensions of products and volume are checked.

Aesthetic requirements: originality, fashion, high quality processing. Compliance with ergonomic requirements is especially important for dishes: convenience and safety in use. Ease of use depends on the size and design. According to the standard, ordinary glass of one grade is good, and crystal products are divided into 1st and 2nd grades.

Quality indicators of ceramic goods.

Ceramic products must comply with the requirements of regulatory documents in terms of quality.

Functional requirements.

Ceramic products must correspond to the functional purpose, such quality indicators as the stability of products on the plane, indicators of water absorption and heat resistance are important.

Ceramic products must meet the requirements of reliability: the dishes must be durable, the attachments (handle, spout) must be firmly fixed.

ergonomic requirements.

Ceramic products should not emit harmful substances from the glaze and ceramic paints, they should be easy to use; the lids must be tightly fitted and not fall out when the products are tilted 70°.

aesthetic requirements.

Dishes made of porcelain and faience should have a white shard (yellowish tint is allowed for faience dishes). The whiteness of porcelain is standardized (60 - 65%).

In layers of porcelain with a thickness of 2 - 2.5 mm. products must be translucent. Products must meet the requirements of the integrity of the composition, the perfection of forms and decoration, must meet the requirements of novelty and originality of style, shape, and be in line with fashion. Defects are not allowed in ceramic products: through cracks, spalls, not polished and not glazed, bubbles (bulging of a shard or glaze with a diameter of 4 mm or more), glaze (cracking) of glaze, peeling of paint and glaze.

Depending on the type, location, size and number of defects, porcelain and faience dishes are divided into 1st, 2nd and 3rd grades. There are defects in the shard, molding, decoration.

On the bottom of porcelain, faience products, on the reverse side, with indelible ceramic paint, the trademark of the enterprise - the manufacturer, the grade, the cutting group is applied. A trademark is denoted by a conventional symbol, letters or the name of the enterprise is written. A red stamp is placed on a product of the 1st grade, blue - of the 2nd, green - of the 3rd grade.

The standards also provide for the packaging of ceramic products.

Packaging, labeling and storage of glass products.

Glass products are marked with a brand, which indicates the name of the manufacturer, trademark, standard number, cutting group. Article, on crystal products - the content of oxides of lead and barium in percent.

Transport glass products with the inscription “ Caution glass”, “Up”, “Do not turn over”.

Glass products cannot be stored for a long time in damp rooms, as the transparency of the glass is partially lost, a white coating may form on the surface.

Glassware is packed in paper, plastic bags in boxes are sprinkled with shavings.

Packaging, labeling and storage of ceramic products.

Ceramic products are packed in packs, boxes; cups of 4 or 6 are packed together with saucers in one pack, first shifting with paper or wrapping products in paper through one.

Several packs of products are laid with paper, shavings and wrapped in an enlarged package. The designation is marked on the package: product name, manufacturer's name, its trademark, packing date, standard number, packer number, grade, cutting group.

Ceramic products should be stored in dry, heated rooms on racks.

Advice to customers and help in choosing a product.

The seller must know the properties, purpose of the goods. In addition to qualified advice, it is important to offer, show and sell goods. Service should be accompanied by an attentive, precautionary attitude towards the buyer. The speech of the seller must be competent, calm, convincing. Calmness, rhythm, dexterity should be distinguished by the working movements of the seller. When serving customers, you need to be a subtle psychologist, select an individual approach to each, protect the dignity of both the buyer and the sales worker.

Used Books.

Bogdanova E.A., Bogdanova G.I. "Light and food industry". Moscow 2001

Kirakozova N.I. "Production of whole milk products". Moscow 2000

A.N. Neverov, T.I. Chalykh, E.L. Pekhtasheva, N.V. Ushakova, O.V. Fukin, I.M. Shcherbakova, D.A. Sorokina, G.I. Zlobina, S.S. Shipilova, N.A. Pankina Commodity research and organization of trade in non-food products. Moscow 2001

N.S. Kozyulin. “Commodity research of non-food products”, Moscow 2002

E. Kuznetsova, S. Vakorin, A. Kolomeytsev “Modern trade”. 2007

Despite the widespread modern materials, which are distinguished by a long service life and good consumer qualities, ceramic products are still relevant. Ceramic cookware is fragile and quite expensive compared to, for example, plastic. However, good thermal conductivity and, most importantly, environmental safety of this material compensates for all its shortcomings.

Competition in the ceramic tableware market is high, including among Russian manufacturers. The situation is complicated by the fact that the capacity of this segment of the Russian market can only be estimated approximately, since it is part of the home goods market and is estimated in conjunction with other segments. It is known that tableware makes up about a third of the total market for all household goods. It accounts for about $700 million.

Despite the fact that products from various materials are presented here - from glass to metal, nevertheless, until recently, ceramic and porcelain dishes were in the lead (about 70% of the total volume of tableware production).

The main trends observed in Russian market ceramic tableware over the past few years, are the annual decline in production volumes (a particularly significant decline occurred in 2009-2010) and a simultaneous increase in unit prices. On the other hand, in early 2009, there was a sharp decline in imports for the depreciation of the ruble and problems with import lending. Now the volume of production of ceramic products in our country is about 250 million items and 2.6 billion rubles in value terms per year, and the annual growth rate of ceramic imports from other countries is 20-30%.

In general, the market growth rate is gradually declining. Experts say that not the best times have come for the production of ceramic and porcelain-faience dishes. Almost no new companies have appeared over the past year, apart from small semi-handicraft enterprises. Most of the factories are closed or redeveloped, as the workload of production is only 10%.

It should be noted that in comparison with Western countries, the ratio of domestic production and imported from other countries (mainly China) has long been in favor of Russian companies, while abroad, local producers have long lost ground to Chinese enterprises. Experts explain this by the fact that since Soviet times, domestic products have been in great demand among consumers due to their high quality. Nostalgia and confidence in the safety of Russian ceramics also play a certain role. Now the situation has changed somewhat.

The main share of sales in the Russian tableware market falls on imported products (especially in the porcelain segment). According to analysts, the volume of porcelain production in our country is reduced by more than 2,000 tons per year. Experts explain this by the obsolescence of equipment and, as a result, low quality and high cost of finished products. Among the countries that supply their products to Russia, China is the leader (about 40% of total imports). And in the segment of products from ceramics and porcelain with an above-average value, European manufacturers prevail. The main importing countries of ceramics: Germany, Czech Republic, Poland, Japan, Great Britain. The share of imported porcelain products in the Russian market is 80%, but every year it is gradually decreasing, which cannot but please domestic manufacturers.

At the same time, the consumption of tableware made from these materials in our country is constantly growing (an increase of about 7% per year). Experts are confident that this figure will increase as the income of the population grows. This is largely due to the rapid development of the HoReCa professional tableware segment (hotels, restaurants, cafes), which accounts for about 20% of the market volume.

The increase in prices for ceramic tableware is mainly due to the increase in the cost of raw materials (the rate of this growth is about 30% per year). About 10% of the raw materials used by domestic ceramic manufacturers are imported from abroad (mainly from Ukraine). Selling price per ton of clay in our country is about $100. The cost of clay imported from Ukraine is almost two times lower. In addition, raw materials from domestic deposits are often inferior in quality to clays from Ukrainian deposits. In our country, several dozen enterprises produce ceramic and porcelain products. Most of it is exported to neighboring countries, as well as to the USA and Germany.

Experts note the following trends in the development of the domestic market of ceramic and porcelain products: consumers prefer glassware, demand is shifting towards the low and medium price segment, demand is growing for everyday products and professional dishes for catering establishments.

There are several classifications of ceramic products. The broadest division - depending on the destination. So, they distinguish industrial and building ceramics, technical, artistic and decorative and household. The first categories include brick, facing and floor tiles, tiles, tiles. And the second two - pottery, dishes (plates, salad bowls, cups, dishes, pots, pans, cocotte bowls, baking dishes, etc.) and decorative items made of porcelain, faience and majolica (aroma lamps, ceramic sculptures, decorative figurines, caskets , aquarium ceramics, vases, lamps, etc.).

Ceramic products, like glass, belong to the category of silicate products. These products are made from plastic clay materials that are fired to give them strength. Depending on the components that make up the composition of the mass, and the firing temperature, ceramics can be either solid or porous. Before firing, part of the products is covered with glaze, which is a thin layer of glassy mass. This is necessary not only for the aesthetic effect: the glaze resists the absorption of dirt and moisture by the ceramic.

Pottery is made from simple colored clays. They can also be glazed and unglazed. Porcelain and faience products are made from white clay and differ in structure: in faience it is porous, while in porcelain it is sintered (solid). Majolica is a product made of white or slightly colored clays with relief patterns on the body, covered with colored glaze. Experts divide ceramics into coarse and fine. The first includes pottery, and the second - products from porcelain, faience and majolica.

For the production of ceramic products, plastic and lean materials are used, as well as fluxes (another name is fluxes). Plastic substances include various types of clays and kaolin. Strictly speaking, kaolin is also a clay substance, usually white in color, which consists of kaolinite. Depending on the impurities that are part of the mixture, clays can have different melting points and a variety of colors.

If the color is associated with the presence of impurities of organic origin in the raw material, then, as a rule, during firing, such a product acquires a white color (such types of clay are called white-burning). These materials are very plastic, but after firing they harden and turn into a shard. Weakening materials are used to reduce the shrinkage of ceramic products. Clay shrinks during drying and firing, which, in turn, can lead to deformation and cracking of the product. Thinning materials, which include quartz, quartz sand, broken shards, etc., prevent this deformation, keeping the shape of the product almost in its original form. Fluxes or fluxes are used for faster and more reliable sintering of the components of the ceramic mass (especially in the production of products from solid ceramics). For this, as a rule, chalk, limestone or feldspar is used.

Opening your own large-scale production is unprofitable. Small companies that work for a specific narrow segment or regional market, it is much easier to survive. Such production does not require large areas and expensive equipment. Main requirement: industrial premises must be located on the outskirts of the city or outside it. In addition, there should be water, heating and electricity. In addition to production space, you will need space for a warehouse, a bathroom, showers.

The necessary equipment of the workshop includes: muffle furnaces, a rolling machine, a "carousel", a ball mill for the production of glaze. To work in the workshops, a minimum of 3-4 workers per shift will be required. In addition, you can not do without an accountant (you can turn to the services of an accounting firm). Responsibilities of a purchasing and sales manager can be taken over for the first time.

Raw materials (white clay), as mentioned above, are usually bought in Ukraine. Therefore, immediately lay down the costs of processing all documents and customs clearance. This procedure will take approximately one week.

Raw materials must undergo special processing: first, they are cleaned of harmful mineral inclusions, then crushed, ground, sieved through a sieve, mixed with other components. A slip is made on the basis of clay - a liquid clay mass with a moisture content of about 35%. It is poured manually or with the help of special equipment into molds and left there until completely solidified. Products of simple shapes (for example, plates) are molded from plastic mass with a moisture content of about 25% in plaster molds using steel templates.

After that, the products are removed from the molds, dried and washed. Drying takes place either naturally (ovens are quite expensive, and small industries do without them), or in convection ovens at a temperature of 70 to 90 degrees Celsius. Firing in kilns is carried out in two stages.

The pottery is then glazed and fired. The full production cycle takes from three to five days. The use of special ovens for drying reduces these terms at least twice. One small workshop produces about 1000 items of products in one cycle.

The impeccable quality of your products is the main condition for its popularity among consumers. When evaluating the quality of ceramic products, three main characteristics are of primary importance: the quality of the sherd, glaze and decoration. Most manufacturers are guided by the so-called "technological regulations for the production of ceramic products."

Decide in advance on the range of products that you will produce. Let it be better small (20-30 items), which will avoid large stock balances. Ceramic dishes (pots, cups, tureens, etc.) are in the greatest demand. Try to regularly update your assortment, removing obsolete models and offering new ones, focusing on the wishes of consumers and demand.

The business associated with the production of ceramic products is not considered seasonal, although this factor still has a certain influence on it. For example, in the southern regions of our country, dishes are in especially high demand from September-October to April. In the hot season, people cook much less often, respectively, the volume of sales of dishes decreases sharply. Also, the work of the production itself can be suspended at high humidity, since ceramics absorb moisture well, which leads to an increase in the number of defects. Consequently, production volumes in a rainy autumn or an overly warm winter will be lower than in other months.

To open own production ceramic products will require at least 3.5 million rubles. The profitability of such a project is about 25-30%, and the payback period is from 3 years. You can buy an existing business (there are enough offers on the market). It will cost 6-7 million rubles (including the lease of production space).

Lilia Sysoeva
- portal of business plans and guidelines

Ceramics is one of the oldest materials used for the manufacture of dishes and art products. It has a number of positive properties: strength, heat resistance, environmental and chemical safety, products made from it have a high aesthetic potential, and this determines its widespread use.
Ceramics are products made from clay (or clay substances) with mineral additives or without them, obtained by molding and subsequent firing. To improve consumer aesthetic properties, ceramics are glazed.
The following materials are used in the production of ceramics:
. plastic - clays and kaolin (a monomineral rock consisting of kaolinite);
. emaciated, reducing shrinkage during drying and firing - quartz sand, alumina, porcelain and earthenware, fireclay;
. fluxes that reduce the sintering temperature and create a glassy phase - feldspar and pegmatite;
. glaze materials.
As factors that form the consumer properties and quality of ceramic art products, the type of ceramics, the method of molding and the type of decoration are distinguished.
Depending on the structure, fine ceramics (glassy or fine-grained shard) and coarse (coarse-grained shard) are distinguished. The main types of fine ceramics are: porcelain, semi-porcelain, faience, majolica, and coarse - pottery.
Porcelain has a dense sintered shard of white color (sometimes with a bluish tinge) with low water absorption (up to 0.2%), it emits a high melodic sound when struck, and can be translucent in thin layers. Due to the double firing of products, the edge of the side or the base of the product is not covered with glaze. The raw materials for the production of porcelain are kaolin, sand, feldspar and other additives.
Semi-porcelain occupies an intermediate position between porcelain and faience in properties, the shard is white, water absorption is 3-5%, and is used in the production of household dishes.
Faience has a porous white shard with a yellowish tinge, the porosity of the shard is 9-12%. Due to the high porosity, faience products are completely covered with a colorless glaze. Glaze has a low heat resistance, so this type of ceramic is used in the production of everyday tableware. It is produced from white-burning clays with the addition of chalk and quartz sand.
Majolica has a porous shard, water absorption is about 15%, products have smooth surface, high gloss, small wall thickness (which is determined by the molding method - casting), are covered with colored glazes and may have decorative relief decorations. For the production of majolica, white-burning clays (faience majolica) or red-burning clays (pottery majolica), floodplains, chalk, and quartz sand are used.
Pottery has a crock of red-brown color (red-burning clays are used), high porosity, water absorption up to 18%. Products can be covered with colorless glazes, painted with colored clay paints - engobe. The range is represented by kitchen and household utensils (pots for roasting, milk jugs) and decorative items.
The production process of ceramic products in a simplified form can be represented by the following steps:
. preparation of raw materials;
. obtaining a ceramic mass;
. molding (manual or mechanized), casting, semi-dry pressing;
. drying and straightening;
. first firing;
. glazing;
. poured roasting;
. decoration.
The quality of ceramic art products is determined by their appearance, durability, compliance with the functional purpose and other technical indicators.
The specificity of the manufacture of ceramic products is associated with the possibility of a large number of manufacturing defects at various stages of this process.
Appearance defects are subdivided into sherd defects, glaze defects and decoration defects. The shard defects are formed at the stages of mass preparation, molding (casting), drying and primary firing. Some of them are immediately noticeable, while others (such as stains) may not appear until after firing. Therefore, for manual and mechanized molding, it is necessary to keep all tools in impeccable cleanliness.
Glazes are glossy alloys that melt on a clay shard with a layer 0.12–0.40 mm thick. The purpose of the glaze is to cover the porous shard of products with a dense and smooth layer; to give the product with a dense crock increased mechanical strength and good appearance; ensure dielectric properties; protect the decor from mechanical and chemical attack.
Decoration - decoration a finished product using decals, stamps, etc. A stamp is used when decorating products with repeating motifs. To apply a stamp to the edge of the product, a stamp roller is used.
The final operation for processing a ceramic product is grinding the edges and legs of the product.
Defects in product molding and their causes
hand molding
Defect: the semi-finished product sticks to the mold.
Reason: the mass was put into the mold with wet hands, the humidity of the mass is uneven, the template is not cleared of the adhering mass, the template is set incorrectly.
Defect: scratches and furrows.
Reason: lack of mass in the form.
mechanized molding
Defect: bottom deflection (usually becomes noticeable only after poured firing).
Cause: Insufficient heating of the central part of the shaping roller, insufficiently maintained vacuum, dirty shaping roller.
Defect: deformation of the edge, noticeable after firing.
Cause: The blank mass is not placed in the center of the mold or is crumpled, the surface of the working cam is dirty, soft mass.
Defect: cracks on the edge.
Reason: new or contaminated molds were used, high drying temperature, low vacuum mass.
Defect: cracks on the leg.
Cause: high roller temperature, low molding speed, fast or one-sided drying, roll center shift when tilted.
Defect: rough surface of the semi-finished product.
Cause: large suction capacity of gypsum molds, overheated molds, poor vacuum, worn gypsum molds.
Casting defects and their causes
Defect: different thickness of the shard.
Cause: non-compliance with the set time for sharding, insufficiently or one-sidedly dried molds, new and old molds are used at the same time.
Defect: deformation.
Cause: semi-finished product sticks to the mold, removed from the mold early, careless removal of the semi-finished product from the mold, uneven drying, sometimes due to draft.
Defect: cracks.
Reason: long keeping of the semi-finished product in the form, fast or one-sided drying, inaccurate trimming of the edge of the neck or spout, stratification of the mass due to insufficient mixing of the slip in the form.
Defect: spots.
Reason: contaminated or stratified mass, the product was taken out of the mold with wet hands.
Drying defects
The cause of defects that appear during the drying process is often difficult to establish, since it can be not only a violation of the regime, but also deviations from technological parameters at previous stages of production.
The composition of the mass has a significant effect on the drying result. The high content of clay components and, as a result, a large amount of swelling water with an incorrectly selected drying mode cause the appearance of defects. During drying, large differences in humidity are formed in the crock, due to which the semi-finished product is deformed.
The reason for the deformation may lie in the molding technology. A large difference between the speed of the spindle and the roller, as well as the strong pressure of the roller, loosens the crock, which, because of this, collapses when heated during drying.
Along with the main types of defects mentioned above, there are also specific ones for each drying method.
Defect: deformation and cracks leading to the destruction of the product.
Reason: intensive drying, which does not take into account the possibility of moisture movement in the semi-finished product.
Defect: the appearance of rust spots.
Reason: non-compliance with the rules for the operation of dryers; metal parts are not coated with anti-corrosion paint.
Firing defects
Firing is one of the most important technological steps in the production of ceramic products. It has a decisive influence on the result of the entire technological process.
Roasting takes place in two stages.
1. First firing. The purpose is to clean and strengthen the shard, since a relatively thin shard of unfired items gets wet during glazing and cannot withstand mechanical stress. Then a layer of glaze is applied to the surface of the product.
2. Poured firing. Purpose - uniform spreading of the glaze, final sintering of the shard.
First firing defects and their causes
Defect: gray color.
Cause: Sulfur deposits during the first firing (visible only after the poured firing).
Defect: cracks.
Cause: Too fast heating or cooling.
Defect: deformation.
Reason: uneven surface of the support, one-sided effect of temperature.
Defects in poured firing and their causes
Defect: cracks with welded edges.
Reason: temperature jump during heating.
Defect: cracks with sharp edges.
Cause: temperature jump during cooling.
Defect: deformation.
Cause: Overburning, often also molding defect.
Defect: yellow color.
Reason: belated or insufficient recovery.
Defect: bluish tint.
Reason: early recovery, insufficient exposure at maximum temperature.
Defect: pins.
Cause: Violation of the gas firing regime, silicon carbide getting into the glaze.
Defect: gray color.
Reason: the presence of sulfur in the fuel.
Defect: brownish edges, as well as matte spots and coatings on the glaze.
Cause: flue gases in the cooling zone.
Defect: insufficient translucency, matte surface.
Reason: low temperature or insufficient firing time.
Defect: high translucency, swelling.
Reason: burnout.
Defect: acne.
Cause: Insufficient first firing temperature or restoration started below 980 °C.
Glazing defects, their causes
and ways to prevent
Defect: glaze assembly.
Reason: contamination of the product with grease, soot, dust.
Prevention of defects: keep clean, carefully dedust the surface, re-fire in case of soot deposits.
Defect: zek (a network of cracks in the glaze layer).
Reason: Too fine grinding.
Prevention of defects: control the degree of grinding.
Defect: leakage (thickening).
Reason: incorrect glazing, very thick glaze layer, insufficient rotation frequency of the product during watering, high glaze density.
Prevention of defects: thoroughly clean or stick together the remains of the glaze, control the density of the glaze (if necessary, reduce it), check the equipment
Defect: fused to the stand.
Cause: Glaze residue on support surfaces, dirty water in the glaze remover.
Prevention of defects: ensure the product is evenly pressed against the stripping belt, change the water more often or use running water.
Defect: baldness.
Cause: Bouncing or erasing glaze.
Defect prevention: avoid collision of products during loading and processing, glue the leg of an unstable product.
Defect: bulge.
Reason: Remaining dust.
Prevention of defects: to ensure good blowing and wet washing of the semi-finished product.
Defect: glazed blockage.
Reason: pieces of mass in the glaze or on the surface of the product after the first firing.
Prevention of defects: sieve the glaze more often, improve the control of products before glazing.
Defect: uneven, wavy glaze.
Cause: strong jet of glaze, high spindle speed.
Prevention of defects: check equipment and re-adjust it, check the composition of the glaze and the temperature of the poured firing.
Defect: crack.
Reason: the temperature coefficient of linear expansion of the glaze is high.
Prevention of defects: check the composition of the glaze.
Defect: glaze swelling.
Cause: dense glaze, the temperature of poured firing is too high.
Prevention of defects: check the density of the glaze suspension, the composition of the glaze and the temperature of the poured firing.
Defect: glaze boiling (bubbles and pimples).
The reason: the rapid rise in temperature during firing, the glaze melted before the end of the outgassing of the shard.

Defect: pin pricks.
Reason: bursting but not closed air bubbles in the glaze, narrow melting interval of the glaze.
Defect Prevention: Extend glaze melting range.
Defect: haze.
Reason: glaze crystallization due to exposure to S02 from furnace gases, low poured firing temperature.
Prevention of defects: check the watered firing mode.
Defects in decorating products with decals and their causes
Defect: Remains of paper under the image.
Cause: Insufficient softening of the decal, waterproof spots (oil, lacquer stains) on the paper: these spots form bubbles that destroy the image.
Defect: paint bubbling.
Reason: insufficiently careful straightening of the decal, residual water under the decal.
Defect: bubbles.
Reason: insufficiently squeezed out water and air from under the decal, the bubbles burst during firing, destroying the paint layer in these places.
Defect: folds.
Cause: Poor straightening and careless application of the decal to curved surfaces.
Defect: whitish spots after firing.
Cause: dirty or hard water was used, the products were not wiped well.
Defect: soiling after decal transfer.
Reason: careless cleaning of the product.
Defect: brittle decal.
Reason: poor varnish, poor paper quality.
Stamping Defects and Causes
their occurrence
Defect: stamp imprint is flattened.
Reason: liquid preparation of gold, uneven pressure on the stamp, thick layer of varnish.
Defect: the stamp imprint is incomplete (there are no individual places in the drawing).
Reason: thick preparation of gold, there were greasy spots (fingerprints) on the product, insufficiently sticky varnish.
Defect: the stamp reproduces thin contours.
Cause: The plunger is worn out and needs to be replaced.
Defect: dirty print.
Reason: soiled stamp (fibers, etc.).
Defect: stamp substrate imprint.
Cause: The backing sticks out of the image.
Defect: strong or weak adherence of powder paint.
Cause: The lacquer film is applied unevenly.
Defect: scratches on the print, powder paint residues in the recesses under the handles and inside hollow products.
Cause: careless powdering and lack of control.
Defect: different tone of products.
Cause: Different amount of kerosene added, poor comparative control.
Defect: color deviation of mixed paints.
Reason: non-compliance with the mixing recipe.
Defect: erasing the contours of the picture.
Cause: Too much kerosene or too much powder paint.