Coursework: Analysis of the range, competitiveness and quality of glassware. Consumer properties of glassware Head: N.V. Karlovska
The usefulness of glass products for consumers is determined, first of all, by their compliance with functional, commercial, ergonomic, aesthetic requirements and reliability in operation. Based on the requirements of various categories of consumers for these goods, it is possible to single out the corresponding consumer properties. They are based on the natural properties of glass, due to its nature, composition and structure, methods of obtaining products, decoration, as well as compliance with the correct packaging, labeling, transportation, storage and operation.
In view of the greatest variety of tableware assortment among all glass household goods, it is advisable to consider a detailed description of the consumer properties of glass products using the example of tableware. It is easy to see that the main functions of glassware are the ability to "receive", preserve and "give" food and drinks. The performance of these functions depends both on the design of the product and on the type of glass. In fig. 10.1 shows the group characteristics functional properties glassware.
Glass type and composition determine the chemical, thermal, atmospheric and mechanical resistance of finished products, ie, their ability to "accept" and preserve food and drinks. The ability to "give" food is determined, first of all, by a constructive decision.
Commercial activities to provide the serviced population with glassware must necessarily provide for a deep knowledge of the consumer properties of products and the requirements of various categories of consumers for individual indicators and in terms of assortment.
Group indicators ergonomic properties provide maximum convenience in use of products and their hygiene (fig. 10.2).
Ease of use glassware determines the degree of comfort, that is, the convenience of holding, carrying, washing, storing, and this is ensured by the general parameters of the product, the shape, size and location of individual parts, and by weight. Hygiene glassware depends on the chemical properties of the glass and design features. It is known that glassware is chemically resistant and harmless, but some paints and compositions used for finishing may not fully meet these requirements due to the content of heavy metal salts in them. Bulky, uncomfortable shape and design of products can also reduce hygiene, making it difficult to clean (wash) in hard-to-reach places.
Glassware, like other products, is designed to fulfill an important aesthetic function, that is, to satisfy the spiritual needs of consumers, to instill in them a taste, a sense of beauty, to contribute to the creation of a cozy home, a sense of comfort at the table. Aesthetic properties are formed at the stage of product design, they are largely determined by the unique properties of glass as a material, and depend on the quality of production execution of operations for the formation and finishing of products.
Integrity of the composition provides for the connection into a single harmonious whole of all the constituent elements of the dishes: the properties of glass, the shape and design of the product, the proportions and ratios of individual parts, decorativeness (Fig. 10.3).
Rationality of form provides for its consistency, conformity of the form to the purpose of the product and the properties of the material, processing technology.
Information expressiveness(informativeness) of tableware is characterized by the degree of reflection in the form of a product of various social and aesthetic ideas and ideas, for example, national, age, regional traditions (symbolism).
Originality of the product determines its difference (dissimilarity) from other similar products.
Reliability is a complex complex property characterized by durability and preservation glassware. Such indicators of durability as reliability and maintainability are not typical for glass products (Figure 10.4). The durability of the cookware is determined, in turn, by its physical and moral durability. The optimal is the coincidence in time of performance of utilitarian and aesthetic functions, i.e., physical and moral wear and tear.
The considered groups and individual indicators of the consumer properties of glassware are formed at various stages of the production of products. This includes design, preparation of raw materials and glass melting, molding, annealing, technical processing, decorative processing.
Ministry of Education of the Republic of Belarus
Educational institution "Minsk State Trade College"
Department: commercial activities commodity research of non-food products
Course work on the topic:
"Analysis of the range and quality of glass household goods in the department store" GUM "
Student group K-84: Titova Nina
Head: N.V. Karlovska
Introduction ………………………………………………………………………………………………
1.Factors shaping quality ……………………………………………………
2. Classification of assortment and consumer properties …………….
3. Analysis of the assortment in the department store "GUM", quality requirements and factors that preserve quality …………………………………………………………….
Conclusion…………………………………………………………………………………………..
List of sources used ………………………………………………….
Introduction
The development of glass production was caused by the great demand for glass products - window glass, mirrors, tableware, which could not satisfy the old glass factories that existed in the 17th century and the desire to abandon the expensive import of foreign glass.
In 1772, factories produced: beer glasses with and without lids, wine and vodka glasses of various sizes, beer glasses, various bottles, icon lamps, salt shakers, cucumber bowls, pocket flasks, inkwells, etc.
From the above historical data, we can conclude that the topic of glass production was relevant for our country already 250 years ago. Nowadays, the traditions and secrets of old masters are preserved, the ability to work with glass is transmitted at the genetic level from generation to generation. Time dictates new trends, but the foundations of the craft remain unshakable.
The work of a blower is a magical sight: a person's breath transforms a drop into a wonderful product. Today, enterprises of our country produce products from glass and crystal: glasses, glasses, wine glasses, bowls, jugs, glasses, beer series, highly artistic shtoffs, salad bowls, high-quality vases, vases for interior decoration, perfume containers, medical bottles that meet the most demanding taste , these are: OJSC Glassworks "Neman", PRUP Borisovskiy Khrustalny Zavod.
Along with domestic manufacturers, recognized world leaders in the production of glassware, such as: KAVALIER glass factories Czech Republic, Italian company Carlo Giannini, etc., are competing for the sales market. The relevance of this topic of the course work is obvious, since the development of glass production is one of the constituent factors of the development of the economy of our country.
The aim of the course work is to analyze the assortment, competitiveness and quality of glassware based on the study of a trading enterprise OJSC "GUM", deepening knowledge, expanding horizons, acquiring professional knowledge for further work with goods.
Work tasks:
1. Study of consumer properties of glassware and factors affecting consumer properties.
2. Study of the range of glassware, its classification and characteristics, as well as sold by the department store of JSC "GUM" on the basis of the analysis.
3. Analysis of the factors that form the quality of the product.
4. Make conclusions based on the work done.
The analyzed enterprise OJSC "GUM" is located at the address: Minsk, Independence Avenue, 21.
The main type of production activity of this enterprise is retail trade, this is the sale of goods to the end consumer, which is the final link in the movement of goods in the sphere of circulation.
In the course work, literary sources of various authors, materials from periodicals, data from regulatory documents were used.
1.Factors shaping quality
Glass products, in accordance with their purpose, are divided into three classes: household, architectural and construction and technical.
Household glass products include tableware, artistic and decorative items for interior decoration, lamp products, mirrors.
Glass is an amorphous body obtained by supercooling a melt, regardless of the composition and temperature of the solidification region. With a gradual increase in viscosity, it acquires the mechanical properties of a solid.
Glass is classified by origin, chemical composition, main properties and purpose.
For the manufacture of household utensils and decorative items, oxide glasses are used, in which the main glass-formers are oxides of silicon, boron, aluminum, etc.
Glasses in which the main glass former is silicon oxide - SiO 2 are called silicate, glasses where the main glass former are boron and silicon oxides are borosilicate, and glasses with the main glass formers in the form of aluminum, boron and silicon oxides are aluminoborosilicate. These oxides form the basis of the glass structure and determine its most important properties.
In addition to these acidic oxides, the glass contains oxides of alkali and alkaline earth metals. Of alkaline oxides, sodium oxides are used - Na 2 O, lithium oxides - Li 2 O, potassium oxides - K 2 O. From alkaline earth oxides: calcium oxides - CaO, magnesium oxides - MgO, zinc oxides - ZnO, barium oxides - BaO, lead oxides - PbO.
Each oxide brings its inherent properties. Therefore, many properties of glass depend on its chemical composition. The composition of the glass is expressed in terms of its constituent oxides.
According to GOST, glass for household utensils and decorative products is divided into the following types: sodium - calcium - silicate, special household, crystal (contains at least 10% of lead, barium, zinc oxides), low-lead crystal (18-24% PbO), lead crystal (24-30% PbO), barium crystal (not less than 18% BaO). Special household glass includes heat-resistant borosilicate and aluminoborosilicate glass.
Sitalls are also used for the manufacture of kitchen utensils. These are non-transparent white glass-crystalline materials of high temperature resistance. They are made by directional crystallization of lithium - aluminosilicate glass in the process of special heat treatment.
Raw materials of glass production are divided into basic or glass-forming, and auxiliary.
Acidic, alkaline and alkaline earth oxides are added to the glass composition with the basic materials.
The main acidic oxide - SiO 2 - is introduced into the glass through quartz sand. The sand should be free of impurities, especially coloring (iron, titanium, chromium oxides), which cause bluish, yellowish, greenish tints of glass, reduce its transparency. With an increase in the content of silicon dioxide in the glass, the mechanical and thermal strength and chemical resistance improve, but the melting temperature rises.
Boron oxide В 2 О 3 is introduced with boric acid or borax. It facilitates melting and improves the physical and chemical properties of glass.
Alumina Al 2 O 3 is usually introduced via alumina. Its addition helps to increase the strength and chemical resistance of glass.
Alkaline oxides Na 2 O, K 2 O are introduced through carbonic (soda, potash) or sulfate salts. They lower the melting temperature of glass, facilitate the formation of products, but reduce strength, heat resistance and chemical resistance.
Alkaline earth oxides are introduced by means of carbonate salts. So, calcium oxide is introduced through chalk or limestone, lead oxide - through red lead or lead lithium.
Oxides of calcium, magnesium, zinc increase the chemical resistance and heat resistance of products. Barium, lead and zinc oxides increase the density, optical properties and therefore are used in the production of crystal. In the production of glass, alkali-containing rocks, waste from mining and processing plants, and non-ferrous metallurgy are widely used. Blast furnace slags, in large quantities - glass breakage.
Auxiliary materials facilitate and accelerate glass melting, color and drown it. According to their purpose, they are subdivided into clarifiers, decolouring agents, mufflers. Dyes, reducing agents and oxidizing agents.
Clarifiers help to remove gases from the molten glass resulting from the decomposition of raw materials.
Decolourants dampen or weaken unwanted color casts.
Silencers (fluorides and phosphates) reduce transparency and give the glass a white color.
Dyes give the glass the desired color. Heavy metal oxides or sulfides are used as dyes. Coloring can also occur due to the release of colloidal particles of free metals (copper, gold, antimony) in the glass.
Glass is painted blue with cobalt oxide, blue with copper oxide, green with chromium or vanadium oxide, purple with manganese peroxide, and pink with selenium, lilac with neodymium oxide, yellow with cerium oxide, cadmium sulfide, etc. Red glasses are especially distinguished - rubies: selenium, copper, gold.
Glassware production
It consists of processing raw materials, making up a charge, melting glass, molding and annealing products, primary and decorative processing.
Processing of raw materials is reduced to cleaning sand and other components from unwanted impurities, fine grinding and sieving materials.
Charge preparation, i.e. dry mixture of materials, consists in weighing the components according to the recipe and thoroughly mixing them until completely homogeneous. A more progressive method is the production of briquettes and granules from a charge; at the same time, the homogeneity of the charge is maintained, and cooking is accelerated.
Cooking glass melt from the charge is carried out in baths and pot furnaces at a maximum temperature of 1450-1550 o C. During the cooking process, complex physical and chemical transformations and interactions of raw materials with the formation and melting of silicates and free silica occur. With the help of clarifiers, the glass mass is freed from gas inclusions. In case of violations of the modes of raw material processing, batch preparation and cooking, molten glass defects are formed in the form of undesirable color shades and foreign inclusions - vitreous (streaks, schlir), gas (bubble, midge), crystalline (stones).
The molding of articles from viscous molten glass is carried out by various methods. This possibility is associated with a gradual increase in glass viscosity with decreasing temperature and high surface tension of glass, which provides a smooth, shiny surface of products. The molding method largely determines the configuration of products, wall thickness, decoration techniques, coloring, and therefore is an important assortment feature and a pricing factor.
Household products are made by hand and free blowing, mechanized blowing, pressing, press blowing, multi-stage method, bending (bending), centrifugal molding.
Manual blowing - with the help of a glass blowing tube using wooden or metal molds, in which the molding is completed when the workpiece (pellet) rotates. This method produces products of any configuration and wall thickness with a smooth and shiny surface. They produce colorless, mass-dyed and overhead products (two-layer and multi-layer). During the blowing process, you can decorate the dishes in various ways.
Free blowing (in the trade - Guten molding) is also carried out by means of a glass blowing tube, but the products are molded and finally finished mainly in air. Products are characterized by the complexity of shapes, smooth transitions of parts, a thickened wall. Decorate them with colored stripes, ribbons, adhesions, etc.
By mechanized blowing on automatic machines (VS-24, R-24, VM-16, R-28, VR-24, etc.), colorless products of simple shapes, mainly glasses, are produced.
The pressing of products is carried out on automatic presses in metal molds under the pressure of the core. Colorless or colored items have a flat, cylindrical, conical shape, expanding at the top. Wall thickness over 3 mm. On the surface, you can see the seams - the junction of the parts of the split forms. They try to overcome some monotony of pressed products by creating a light relief pattern on the surface (textured press), pressing without an upper ring, which makes it possible to obtain a freely formed edge for each product, combinations of pressing and bending (press-bending).
Press-blowing on machines G-28, PMV, LAM-2 produces glasses and dishes of complex shapes - decanters, bottles, etc. on automatic lines "Interglass" press-blowing produces glasses. In this case, the bowl is blown out, and the bottom and the leg are pressed and welded to the bowl. Other molding methods are less common.
Possible defects in molding - curvature of products. Asymmetric attachment of parts, wall thickness variations, folds, wrinkles, scratches, small cracks (cuts) of the surface, etc.
During molding, due to the low thermal conductivity of glass, sharp and uneven cooling, residual stresses arise in the products, which can cause their spontaneous destruction. Therefore, annealing is mandatory - this is a heat treatment, consisting in heating the products to 530-550 ° C, holding at this temperature and subsequent slow cooling. During annealing, residual stresses are weakened to a safe value and are evenly distributed over the cross section of the products.
Primary processing consists in removing the cap of the products after hand blowing, processing the edges and bottom of the products, lapping the caps to the neck of decanters and bottles. In pressed products, the surface is polished by fire.
Decorative processing is the application of adornments (cuts) of a different nature to products. The decor largely determines the aesthetic merits of the tableware; it should emphasize the transparency, brilliance and play of light of glass, features of the shape of products and have an independent artistic value. Decor is an essential feature of the assortment, one of the main pricing factors.
Cuttings are classified according to the stage of application (hot and cold), types, complexity.
Decorating blown products in a hot state is carried out by applying glass cakes, colored chips, ribbons, twisted and tangled threads. Colored spots. The "crackle" cut is used - a network of small surface cracks formed when the set is rapidly cooled in water or in wet sawdust. Using special techniques, they create a pattern of air bubbles, ribbons, threads in the thickness of the glass. A groove "for a roll" is used, which creates an optical effect due to the wavy inner surface formed when the workpiece is blown in a ribbed shape. Iridescent films (irrigation) on the surface of products can be obtained by precipitation of salts of tin chloride, barium, etc. on a hot product; these salts, decomposing, form transparent, shiny iridescent films of metal oxides. Peculiar patterns of different colors and transparency are obtained using zinc sulfide glass.
Decorating hot blown products is very difficult, but it perfectly reveals the properties of glass, gives the products uniqueness and originality. Pressed products are decorated mainly due to the design from the molds.
The decoration of products in a cold state is carried out by means of mechanical processing (shaped grinding), chemical processing (etching) and surface decoration using silicate paints, gold preparations, chandeliers.
Mechanically applied cuts include matte tape, numbered grinding, diamond edge, flat edge, engraving, sandblasting.
Matte tape is a strip 4-5 mm wide. Numbered grinding - a matte surface pattern made of round, oval sections or notches.
A diamond facet is a pattern of deep two-sided grooves, which, when combined with each other, form bushes, grids, polygonal stones, simple and multi-rayed stars and other elements. The pattern is applied on manual or automatic glasses using an abrasive wheel with a different edge profile. After cutting the pattern, it is polished to full transparency. The diamond edge is especially effective on crystal items, where the brilliance and play of light in the edges are well revealed.
A flat face is polished planes of various widths along the contour of products.
Engraving is a surface matte or, less often, a light pattern of a predominantly vegetative character with a careful study of details.
Sandblasting - a matte pattern of various textures. Formed during the processing of glass with sand, which is fed under pressure to the cutouts of the stencil.
Etching cuttings are subdivided into simple (helioshirny) etching, complex (pantographic), and deep (artistic) etching. To obtain a pattern, the products are covered with a layer of protective mastic, on which a pattern is applied with machine needles or manually, exposing the glass. Then the dishes are immersed in a bath with a mixture of hydrofluoric and sulfuric acids, which dissolve the glass along the exposed pattern to different depths.
Plain or helioshire etching is an in-depth transparent geometric pattern in the form of straight, curved, broken lines.
Complex or pantograph etching is a linear in-depth pattern, but of a more complex, often vegetal character.
Deep or artistic etching is a relief drawing of a mostly vegetative subject on two-layer glass. Due to the different etching depth of colored glass, a convex pattern of different color intensity is formed. Cutting is very time consuming.
Surface decoration with silicate paints, gold preparations, chandeliers is painting, application of ribbons 4-10 mm wide, layering 1-3 mm, antennae up to 1 mm, decals (decalcomania), photographic images, etc. Drawings are fixed by firing at a temperature of 550-600 o WITH.
New methods of decoration are being developed - plasma spraying of metals, glass powders, photochemical engraving, etc.
The production process ends with acceptance control and product labeling. Blown, press-blown products are marked by sticking a paper label indicating the plant's trademark, standard number, litter (crystal blown), cutting group, price. Pressed products are marked with an imprint of the necessary data on the bottom of the products during molding.
2. Classification of assortment and consumer properties
The range of glass products is quite dynamic and changes due to the constant development of science, the state of production technology, the nature of consumer demand, and a change in style.
The assortment of household products is classified according to purpose and operating conditions, composition and color of glass, molding method and the nature of heat treatment, types (names), sizes, styles of products, methods and complexity of decoration, completeness.
According to their purpose, household goods are divided into tableware and decorative items for table setting and interior decoration, household dishes for storing food and home canning, kitchen utensils for cooking, lamp products (table lamps, lamp tanks, lamp glasses) and mirrors.
According to the composition of the glass, dishes are distinguished from sodium - calcium - silicate, special household and crystal glass. Tableware is made from sodium - calcium - silicate glass, crystal of various types, as well as from muted borosilicate glass; household dishes made of sodium - calcium - silicate glass with additives that increase chemical and thermal stability; kitchen - made of special household glass and sitalls.
By color, they distinguish dishes made of colorless glass, colored (dyed in the mass) and overhead (two-layer and multi-layer). Colored glasses are named according to their color tone (yellow, pink, green, etc.), by the nature of the dye (cobalt, manganese), by analogy with precious stones: rubies (red), topaz (yellowish brown), sapphires (light blue ), emeralds (light green).
According to the method of molding, dishes are distinguished by hand, free, machine blowing, pressed, press blown, multi-stage molding, bending, centrifugal production.
By the method of heat treatment, unreinforced dishes are distinguished, i.e. annealed and hardened by quenching. The overwhelming majority of high-quality glass products and all crystal products are produced annealed.
Quenching consists in heating products to 700 ° C and subsequent rapid and uniform cooling by blowing air. At the same time, high, evenly distributed residual stresses arise in the glass, increasing the impact strength by 5-8 times, and heat resistance by 2-3 times. Some types of pressed tableware and cookware made of heat-resistant borosilicate glass are hardened by quenching.
Types of glassware. There are about thirty types of tableware: these are glasses, goblets, wine glasses, wine glasses, wine glasses, jugs, decanters, sugar bowls, butter cans, table setting vases (for fruits, jam, cookies, cream, sweets, salad bowls), dish, etc.
Decorative items are glass sculptures, flower vases, toilet utensils, horn-shaped glasses, dishes, etc. Each type of product is produced in several varieties, differing in size and style.
In terms of size, dishes are divided into small, medium, large, and extra large. The size of the products is characterized by their diameter, length or height, and the size of the hollow products is characterized by their capacity.
According to the style, the products are subdivided taking into account the shape of the body (ball, oval, cone, etc.), the presence of adhered (handle, leg, lid holder) and removable (cork, lid) parts, the nature of the edge (smooth, cut) and the bottom of the products. The dishes are produced with a bottom of normal thickness, thickened, as well as on a pallet (a ledge or ledge in the lower part of the product).
The leg of the products can be of different heights, shapes (straight or curly) and processing (faceted and even).
Blown flower vases, depending on the complexity of the form, are divided into three groups.
The style, along with the aesthetic features of the molten glass and cutting, largely determines the artistic expressiveness of the products. It is subject to change according to style requirements. Currently, festive and giftware dishes are distinguished by a complex silhouette, meticulous workmanship and intricate shape of details. Household utensils have simpler and more solid shapes.
According to the method of decoration, they distinguish between smooth and decorated dishes. Decorated dishes, depending on the nature, complexity and artistic merits of the cut are divided into group and non-group. Cutting of group blown glassware from high-quality colorless glass is subdivided into 1-7 groups, from colored glass - into 3-8 groups, from overhead glass - into 4-8 groups. Cutting of crystal products belongs to the 4-10th difficulty groups.
The group is united by drawings of the same complexity, but with a different plot. They are designated by three-digit numbers, in which the number in the hundreds indicates the group number.
Non-group items are characterized by originality of forms, complex, often combined designs of high artistic value. They are individual for the products of each plant.
The cutting of pressed products is not subdivided into complexity groups. Modern trends in the decor of glassware - expanding the range of colored glasses, a combination of colored and slightly dimmed glass in the overlay, contrasting combinations in the pattern of elements of a diamond facet, matte engraving, a chandelier, the wide use of decal and silk-screen prints of various subjects, picturesque cuts with paints and gold, often in combination with matting. Curved cuts and products are still popular.
According to the completeness, one-piece products are distinguished, sets (include products of the same type - a set of glasses, etc.), devices (include products of different types of the same purpose) - for water, jam, and other products of the sets are characterized by the unity of the artistic and constructive solution. The assortment of tableware for table setting is extremely diverse and is grouped taking into account all the previously mentioned characteristics. The main types of products: glasses, mugs, cups, wine glasses, wine glasses, wine glasses, wine glasses, decanters, jugs, milk jugs, table setting vases, butter cans, sugar bowls, etc.
Household utensils are produced by manual or mechanized method of their colorless and semi-white glass. The assortment includes thermoses and other food storage products - jars, jars for pickles and jams, barrels, bottles for storing liquids, jars for bulk products.
Thermoses are subdivided according to their purpose into thermos for liquids and food (with a wide mouth), according to the capacity of the flask, design and material of the shell (metal, plastic, combined).
Cookware made of heat-resistant glass and sitalls is represented by pots of various capacities, baking dishes, braziers, pans. Sitall is used to produce sets of pots and a set "Kid". Cookware made of heat-resistant glass is tempered and not decorated. Sitall cookware of white color with a smooth shiny surface is additionally decorated with drawings.
Consumer properties of glass products
Factors of the formation of consumer properties and the range of glass products. Consumer properties and the main features of the range of glass products are formed at the design and construction stage when creating prototypes and in the process of serial production. When developing new products, the artist takes into account the conditions of their operation, the molding method, the need to ensure ease of use and durability of products, the requirements of the artistic style and fashion. Based on this, the composition and color of glass, the configuration of products in general and in details, wall thickness, decoration method, etc. are determined.
The prototype must be accurately reproduced in serial (mass) production. The quality of its reproduction, i.e. the quality of the manufacture of products depends on compliance with the production technology.
The main consumer properties of glass household products are functional, ergonomic, aesthetic and reliability properties.
The functional properties of glassware provide for the ability to perform two main functions: to "accept" and keep food and drinks in constant quantity and quality, and to "give" them in whole or in part as needed. These properties depend on the nature of the glass, the shape, size and purpose of the products, the characteristics of food and drinks. All these factors determine the variability of the shape and size of the products.
The ability to "accept" and preserve food and drinks is determined by the following group indicators: chemical resistance to food and drinks, resistance to weathering, resistance to heat, resistance to mechanical stress. Ability to “give away” food and drinks: functionality of a volumetric-spatial solution and versatility.
Ergonomic properties predetermine, first of all, the convenience (comfort) of use and hygiene of glassware. The comfort of household utensils is determined by the convenience of holding, carrying, performing the functions of storage, washing, as well as the convenience of transportation and storage. Hygienic properties are primarily due to the nature and properties of glass and are characterized by such group indicators as harmlessness and contamination.
The aesthetic properties of glass household goods are determined by the integrity of the composition, rationality of form and information content. The integrity of the composition characterizes the arrangement, addition and connection of parts into a single whole in a certain order. It is due to the spatial and decorative structure, proportions of the shape of glassware, tectonics.
The rationality of the form characterizes the conformity of the form of the product to the functional purpose and environmental conditions, the conformity of the tonal and color solutions of individual elements to the requirements of ergonomics, the style solution - to the interior, manufacturing technology - to the properties of the material. The information content of glassware is determined by the symbolism, originality and compliance with their style and fashion prevailing at a given time.
The properties of the reliability of glass products are determined by their durability and preservation. Of greatest importance is durability, which is characterized by physical and moral wear and tear.
Indicators of a number of consumer properties of products are indicators of the physical and chemical properties of glass. The most important of these are the following:
The density of the glass varies from 2.2 g / cm 3 for quartz glass to 3.0 g / cm 3 and more for high-lead crystal. It depends mainly on the presence of heavy metal oxides (lead, barium, zinc) in the glass composition and affects the weight of products, optical and thermal properties. With an increase in density, the refractive index of light, brilliance and play of light in the edges increase, but heat resistance, strength and hardness decrease.
The mechanical properties of glass are characterized by the absence of plastic deformation, high compressive strength (500-800 MPa). Strength depends on the chemical composition: it increases from the presence of SiO 2, Al 2 O 3, B 2 O 3, MgO in the glass composition and decreases from the presence of alkali PbO oxides. However, the decisive influence is exerted by the internal structure of the glass, the state of the surface, and the presence of defects on it. Strength is increased by quenching, ion exchange in molten salts, applying metal oxide coatings to the surface and other methods. The thermal properties of glass are characterized by a very low thermal conductivity, significant heat capacity and thermal expansion. The thermal stability of products increases with an increase in the mechanical strength of glass, thermal conductivity and with a decrease in thermal expansion and heat capacity. The measure of thermal resistance is the temperature difference that the product can withstand without destruction. The heat resistance of quartz glass is 1000 ° C, glassware made of high-quality glass is 95 ° C, glassware made of sitalls is 300-600 ° C. All methods that increase the mechanical strength, at the same time, improve heat resistance.
The optical properties of glass are varied. Glasses can be transparent (transmittance 0.85 or more) and dim to varying degrees, colorless and colored, with a shiny and matte surface. Optical characteristics of glasses - refractive indices and average dispersion, reflection and transmission coefficients; color indicators largely determine the aesthetic merits of the dishes. The ability of glass to perceive colors that enhance the emotional expressiveness of products is especially important.
The chemical resistance of glass determines the purpose and reliability of products. It is very high especially in relation to water, organic and mineral acids. Alkalis and alkali carbonates are more aggressive. Hydrofluoric acid dissolves glass and is therefore used for patterning, matting and chemical polishing of products.
In terms of water resistance, glass is divided into five hydrolytic classes: the first class is glass that cannot be changed by water, the fifth is unsatisfactory.
According to GOST “Sorted glassware. Nomenclature of indicators "to consumer properties and their indicators include the following:
1.indicators of purpose - chemical composition and density of glass, shape and main dimensions of products, their stability on a flat surface.
2. indicators of reliability - impact strength, hardness, heat resistance, water resistance, strength of fastening of parts, indicators of annealing quality.
3.Indicators of ergonomic properties - the content of harmful substances.
4.indicators of aesthetic properties - the accuracy of reproduction of the author's sample, indicators of compositional integrity, information expressiveness, perfection of manufacturing products, as well as refractive indices, average dispersion, light transmission, cutting angle.
5. economic indicators - the mass of products (consumption of raw materials), cost.
3.Analysis of the assortment in the department store of JSC "GUM"
OJSC "GUM" on the basis of a contractual system works with many suppliers of glassware: OJSC Glassworks "Neman", PRUP Borisovsky Crystal Plant, OJSC "Posuda", LLC "Experimental Glass Plant", "Sun Gobain Vidors", etc.
Basically, all factories specialize in traditional and modern tableware decoration. LUMINARK glass products deserve great attention, which is resistant to temperature changes up to 60 o C. The dishes can be washed in dishwashers. Due to the high quality of drawing, it withstands more than 10,000 wash cycles.
The enterprises pay special attention to the hygienic safety of products. All dishes are certified. The largest specific weight in terms of quantity and amount of goods sold was made by the group of tableware. this product is in the greatest demand among buyers. The products of the "Neman" plant are more popular. He produces the highest quality and most beautiful products.
Borisov Crystal Factory is inferior to other factories in terms of the quality of its products. Some batches of goods manufactured under the press were processed, because The production process was disrupted, and most of the products were deformed.
I noticed that low-quality products still ended up on showcases in the department store. Some goods were not packed in consumer group or individual and transport containers, which caused a breakdown of the goods.
Assortment list of supplied products from suppliers:
Glasses (for red wine, champagne)
Glasses (for whiskey, water, juice, beer)
Fruit slides
Glasses (for vodka, liqueur, port)
Wine glasses (for champagne, water, white and red wine, cocktails, cognac, brandy)
Salad bowls
Pans
Fruit vases
Sets of containers
Ashtray
Caviar dishes
Sugar bowls
Spice Decanters
Requirements for the quality of glass products:
The quality of glassware and decorative glassware must meet the requirements of GOST. According to GOST, in the general technical requirements, products that do not spoil the presentation are allowed:
Processed chips;
Sparsely located swil;
Rarely located "midge";
A crescent-shaped bubble at the junction of individual parts of the product and decorative elements;
Remelting the edge;
Traces of surface disturbance;
Traces from molds and scissors;
Traces of distillation and polishing;
Misbehavior and lengthening of drawing lines;
Defects in decoration with preparations of precious and other metals, luster and silicate paints;
Torsion in mechanized products;
Thickening with one projection on the upper edge of the glasses made of soda-lime-silicate glass;
Waviness of the surface of the faces;
Deviation in the drawing from the reference sample caused by the need to eliminate the defect;
Asymmetry of the junction of the vessel and the bottom, annular thickening or waviness at the junction of the vessel and legs, legs and bottom.
Marking:
Product marking is applied to a paper label, which is glued directly to the product (the use of silicate glue is not allowed) or during production. Marking of consumer (group or individual) containers, group paper packaging and shipping containers is applied to a paper label or stamp.
It is allowed not to apply marking on consumer packaging, packed in transport.
The following information is indicated on the product labeling on the paper label:
mass fraction of lead oxide (only for lead crystal)
designations of this standard
manufacturer's trademark or name
A label is placed on each product. In sets, the label is placed on at least one product, in sets - on the largest one.
It is allowed not to indicate the article in the marking of products packed in individual containers.
The marking in the process of development must contain the trademark or the name of the manufacturer.
The composition of the set or service is indicated on the consumer container or on the largest product.
It is allowed, upon agreement with the consumer, not to mark the products or to apply to some of the products in a batch.
Products intended for export are labeled in accordance with the terms of the agreement or contract.
The following data are indicated in the marking of consumer (group or individual) packaging and group packaging made of paper:
number of products in packaging units (for group packaging)
designation of this standard
trademark and / or name of the manufacturer
product name
For certified products, the conformity mark or the number of the conformity certificate is affixed in the product labeling on the paper label and (or) in the container and packaging labeling, as well as in the shipping documentation. Transport marking - in accordance with GOST with the application of a manipulation sign "Fragile - Caution".
It is allowed to apply an image of a manipulation mark on a label intended for marking containers.
Package
Products are packed in consumer and shipping containers. Specific types of containers and packaging that ensure the safety of products during transportation, the gross weight is indicated in contracts for the supply of products between the manufacturer and the consumer.
Safety requirements
The permissible migration of harmful substances emitted from glass products in contact with food is established by the State Sanitary and Epidemiological Supervision authorities in the relevant regulatory documents approved in the prescribed manner, and in their absence - in accordance with the appendix. Water resistance must be at least IV hydrolytic class (4/98). Glasses and saucers for tea, plates for hot food must be thermally stable. Blown products should be destroyed at temperature drops of 95-70-20 о С, pressed - 95-60-20 о С.
The following are not allowed on the products: chips, cut edges, adhered pieces of glass, cutting and crumbling glass particles when decorating products "in bulk", through cuts, foreign inclusions that have cracks and cuts around them. The end surface of the top edge and the seams of the products must be smooth. The decorative coating applied to the inner surface of products in contact with food must be acid resistant. The fastening of the handles of products and decorative elements must be durable.
Acceptance rules
Products are accepted in batches. A batch is a certain number of products of the same assortment made of glass of the same type. The batch acceptance results must be confirmed by the technical control department.
To establish the group, the height and diameter of the products are determined with any measuring instrument, the capacity is determined using measuring dishes.
Defects in glass products
Waviness is a defect in glass containers in the form of surface irregularities that cause optical distortion.
Deformation is a defect representing a change in its shape as a result of a violation of the modes of formation or heat treatment.
Ovality of the body - deformation of the glass container in the form of a deviation from the roundness of the cross-section of the body.
Ovality of the corolla is a deviation from the roundness of the cross-section of the corolla of the neck.
The concavity of the end of the rim is the deviation from the flatness of the end of the rim of the neck.
Foreign inclusion is a solid opaque inclusion that differs from glass in its physical and chemical properties.
Refractory stone - foreign inclusion in glass in the form of particles of refractory products.
Charge stone - foreign inclusions in the glass from untested components of the charge.
Black point - foreign inclusions in the glass of scale, undissolved chromium compounds.
Crystallization stone is a foreign inclusion that has a crystalline structure as a result of crystallization of molten glass.
Glassy inclusion - an inclusion that has a glassy structure, which is distinguished by its physicochemical properties.
Swil is a vitreous inclusion in the form of threads of arbitrary shape, knots, bundles.
Schlier is a glassy inclusion in the form of a drop.
Forging is a defect in the surface of a glass product in the form of fine waviness, which forms as a result of contact with molding surfaces with a low temperature.
A wrinkle is a slight irregularity on the surface.
Non-perpendicularity of glass containers - deviation from the index of perpendicularity of the vertical axis of the plane of the bottom of the product.
Surface cut - cracks that do not pass through the entire thickness of the wall or bottom.
Glass abrasion is a defect in a glass product representing surface scratches resulting from contact with hard materials or with each other.
Glass adhesion - adhered pieces of glass, chips in the areas of contact of glass products with each other at an elevated temperature of heat treatment.
Bubble - cavities of various sizes.
Glass thickness variation, cut through, fold, chip, glass dust, seam, corner, burr, glass roughness, etc.
Conclusion
The range of tableware is very large and varied. Now every consumer can choose any product for himself, taking into account his needs, tastes, etc. Glassware is very popular despite its fragility. Although safety glass products are now beginning to be popular.
The development of glass production is one of the constituent factors for the development of the economy of any country. For the manufacture of household utensils and decorative items, oxide glasses are used, in which the main glass-formers are oxides of silicon, boron, aluminum, etc. The production of glass products consists of processing raw materials, composing a charge, cooking, molding, annealing, and processing. Consumer properties and the main features of the range of glass products are formed at the design and construction stage when creating prototypes and in the process of serial production. The range of glass products is quite dynamic and changes due to the constant development of science, the state of production technology, the nature of consumer demand, and a change in style.
The assortment of household products is classified according to purpose and operating conditions, composition and color of glass, molding method and the nature of heat treatment, types, sizes, styles of products, methods and complexity of decoration, completeness. The consumer properties of glass products determine the possibility of their intended use, convenience and reliability in operation, beauty and artistic expressiveness. They depend on the perfection of the author's design, the properties of the glass and the quality of the workmanship. Products must be manufactured in accordance with standards, labeling and packaging must comply with the requirements of the standards. They limit possible product defects.
As a result of a well-established supply system, the department store of JSC "GUM" receives a large assortment of glassware, various series of glasses, glasses, bowls from leading manufacturers.
With the improvement of the situation in the economic sphere, there will be tendencies for an increase in trade turnover and profit.
Glass is a material that has very special, only inherent properties, which vary greatly depending on the methods of its manufacture and processing. It can be completely colorless, possess exceptional transparency and, at the same time, perceive unusually bright, rich colors, as well as be translucent or muffled, and, finally, like precious stones, - dull. It lends itself to a wide variety of mechanical and chemical processing methods.
Glassware will always be popular and will remain in vogue. Everyone has them in the house, decorating tables at holidays and delighting guests. Thanks to the huge variety, we can enjoy all the beauty and sophistication of glass products.
List of sources used
V.E.Sytsko "Merchandising of non-food products"
Matveev "Merchandising of household goods"
Ilyin "Merchandising of household goods"
Handbook of the commodity expert of non-food products (in 3 volumes)
A.P. Snitko "Examination of goods: a tutorial"
Site "www.GYM.by"
"Merchandising and examination of goods"
Articles "ArtDecor"
Introduction ……… 3
1 Factors of formation of consumer properties and assortment
Glassware. …… ... 5
1.1 Materials that make up the glass ... ... .5
1.2 Glassware production ..… ..6
2 The range of consumer properties of glassware ... .11
2.1 Basic consumer properties of glassware ... .... 11
2.2 Physical and chemical properties of glass …… ..12
Conclusion ……… ... 14
List of sources used …… .16
Appendix A Nomenclature of consumer properties
glassware …… ..17
Introduction
Glass making in Russia arose in the 9th - 10th centuries, i.e. much earlier than in America (17th century) and earlier than in many other countries of Western Europe (England, Sweden, Venice, Bohemia, Lorraine, Normandy, etc. .).
The general industrial upsurge, which began in the reign of Peter I, also captured the glass business. The development of glass production was caused by the great demand for glass products - window glass, mirrors, dishes, which could not be satisfied by the old glass factories that existed in Moscow Russia in the 17th century (Dukhannsky, Izmailovsky, Chernogolovsky) and the desire to abandon the expensive import of foreign glass. The range of products of the Yamburgsky plant's dishware department was very large. So, for example, in 1722 the plant produced: beer glasses with and without lids, wine and vodka glasses of various sizes, beer glasses, vodka, various bottles, lamps, salt shakers, cucumber bowls, pocket flasks, inkwells, etc.
From the above historical data, we can conclude that the topic of glass production was relevant for our country many years ago.
Nowadays, the traditions and secrets of old masters are preserved, the ability to work with glass is transmitted at the genetic level from generation to generation. Time dictates new trends, but the foundations of the craft remain unshakable.
The work of a blower is a magical sight: a person's breath transforms a drop into a wonderful product. Today, enterprises of our country produce products from glass and crystal: glasses, glasses, wine glasses, decanters, jugs, bowls, glasses, beer series, highly artistic shtoffs, salad bowls, varietal vases, vases for interior decoration, perfume containers, medical bottles that meet the most discerning taste.
Along with domestic manufacturers, recognized world leaders in the production of glassware, such as the KAVALIER glass factories of the Czech Republic, the Italian company Carlo Giannini, and others, are fighting for the sales market.
The relevance of this topic of work is obvious, since the development of glass production is one of the constituent factors of the development of the economy of our country.
The purpose of the work is the study consumer properties of glassware and factors influencing them.
Objectives of this work :
1 to study the factors of the formation of consumer properties and the range of glassware;
2 determine the basic f isicochemical properties of glass and their relationship with consumer properties of glassware;
3 to determine the main consumer properties of glassware.
1. Factors of the formation of consumer properties and the range of glassware
1.1 Materials that make up glass
GlassIs an amorphous body obtained by supercooling a melt, regardless of the composition and temperature range of solidification. With a gradual increase in viscosity, it acquires the mechanical properties of a solid.
Raw materialsglass production is divided into main, or glass-forming, and auxiliary.
With basic materials acid, alkaline and alkaline earth oxides are added to the glass.
Major acidic oxide - SiO 2 - is introduced into glass through quartz sand. The sand should be free from impurities, especially coloring (oxides of iron, titanium, chromium), which cause bluish, yellowish, greenish tints of glass, reduce its transparency. With an increase in the content of silicon dioxide in the glass, the mechanical and thermal strength and chemical resistance improve, but the cooking temperature rises.
Boron oxideIn 2 O 3 is introduced with boric acid or borax. It facilitates cooking, improves the physical and chemical properties of glass.
Aluminium oxideA1 2 O 3 is usually introduced through clay-earth. Its addition helps to increase the strength characteristics and chemical resistance of glass.
Alkaline oxidesNa 2 O, K 2 O is introduced through carbon dioxide (soda, potash) or sulfate salts. They lower the melting temperature of glass, facilitate the formation of products, but reduce strength, heat resistance and chemical resistance.
Alkaline earthoxides are usually introduced by means of carbonate salts. So, calcium oxide is introduced through chalk or limestone, magnesium oxide - through magnesite or dolomite, lead oxide - by means of red lead or lead lithium.
Oxides of calcium, magnesium, zinc increase the chemical resistance and heat resistance of products. Barium, lead and zinc oxides increase the density, optical properties and therefore are used in the production of crystal. In the production of glass, alkali-containing rocks, wastes from mining and processing plants, non-ferrous metallurgy, blast-furnace slags are widely used, and glass breakage is used in large quantities.
Supporting materials facilitate and accelerate glass melting, color and drown it. According to their purpose, they are subdivided into clarifiers, decolouring agents, mufflers, dyes, reducing agents and oxidizing agents.
Clarifierscontribute to the removal of gases from the molten glass formed during the decomposition of raw materials.
Decolorizers extinguish or weaken unwanted color shades.
Mufflers(fluorides and phosphates) reduce transparency and cause the glass to be white.
Dyesgive the glass the desired color. Heavy metal oxides or sulfides are used as dyes. Coloring can also occur due to the release of colloidal particles of free metals (copper, gold, antimony) in the glass.
The glass is painted blue with cobalt oxide, blue with copper oxide, green with chromium or vanadium oxide, purple with manganese peroxide, and pink with selenium, blue with neodymium oxide, yellow with cerium oxide, sulfurous cadmium, and others. Red glasses - rubies: selenovy, copper, gold are especially distinguished.
1.2 Glassware production
The production of glass products consists of the processing of raw materials, the composition of the charge, the melting of the glass mass, the molding and annealing of the products, their primary and decorative processing.
Raw material processingcomes down to cleaning sand and other components from unwanted impurities, fine grinding and sieving materials.
Batch preparation,i.e. dry mixture of materials, consists in weighing the components according to the recipe and thoroughly mixing them until they are completely homogeneous. A more progressive method is the production of briquettes and granules from a charge; at the same time, the homogeneity of the charge is maintained, and cooking is accelerated.
Cooking glass melt from a batch carried out in baths and pot furnaces at a maximum temperature of 1450-1550 ° C. In the cooking process, complex physicochemical transformations and interactions of raw materials with the formation and melting of silicates and free silica occur. With the help of clarifiers, the glass mass is freed from gas inclusions, "thoroughly mixed until uniformity in composition and viscosity is achieved.
In case of violations of the modes of processing of raw materials, preparation of a charge and cooking, defects in the molten glass are formed in the form of undesirable color shades and foreign inclusions - glassy (swill, schlir), gas (bubble, midge), crystalline (stones).
Forming products from viscous glass melt carried out in a variety of ways. This possibility is associated with a gradual increase in glass viscosity with decreasing temperature and high surface tension of glass, which provides a smooth, shiny surface of products. The molding method largely determines the configuration of products, wall thickness, decoration techniques, coloring, and therefore is an important assortment feature and price-determining factor.
Household products are made by hand and free blowing, mechanized blowing, pressing, press blowing, multi-stage method, bending (bending), centrifugal molding.
Hand blowing - with the help of a glass blowing tube using wooden or metal molds, in which, when the workpiece (pellet) rotates, the molding is completed. This method produces products of any configuration and wall thickness with a smooth and shiny surface. They produce colorless, mass-dyed and overhead products (two- and multi-layer). During the blowing process, you can decorate the dishes in various ways.
Free blowing (in trade - Guten's molding) is also carried out by means of a glass blowing tube, but the products are molded and finally finished mainly in air. Products are characterized by the complexity of shapes, smooth transitions of parts, a thickened wall. Decorate them with colored stripes, ribbons, bubbles, adhesions, etc.
Mechanized blowing automatic machines (VS-24, R-24, VM-16, R-28, VR-24, etc.) produce colorless products of simple outlines, mainly glasses.
Pressing productscarried out on automatic presses in metal molds under the pressure of the core. Colorless or colored items have a flat, cylindrical, conical shape, expanding in the upper part. Wall thickness over 3 mm. On the surface, you can see the seams - the junction of the parts of the split forms. They try to overcome some monotony of pressed products by creating a light relief pattern on the surface (textured press), pressing without an upper ring, which makes it possible to obtain a freely formed edge for each product, a combination of pressing and bending (press molding).
Press blowingon the machines G-28, PMV, LAM-2 they produce glasses and dishes of complex shapes - decanters, bottles, etc. On the automatic lines "Interglass" press-blowing produces glasses. In this case, the bowl is blown out, and the bottom and the leg are pressed and welded to the bowl.
Other molding methods are less common.
Possible forming defects - curvature of products, asymmetric attachment of parts, wall thickness variation, folds, wrinkles, scratches, small cracks (cuts) of the surface, etc.
During molding, due to the low thermal conductivity of glass, sharp and uneven cooling, residual stresses arise in the products, which can cause their spontaneous destruction. Therefore, it is mandatory annealing- heat treatment, consisting in heating products to 530-550 ° C, holding at this temperature and subsequent slow cooling. During annealing, residual stresses are weakened to a safe value and are evenly distributed over the cross section of the products.
Primary treatments consists in removing the cap of the items after hand blowing, processing the edges and bottom of the items, lapping the caps to the neck of decanters and bottles. In pressed products, the surface is polished by fire.
Decorative processing - this is the application of decorations (cutting) of a different nature to products. The decor to a large extent determines the aesthetic merits of the tableware; it should emphasize the transparency, brilliance and play of light of glass, features of the shape of the products and have an independent artistic value. De-cor is an essential feature of the assortment, one of the main pricing factors.
Cuttings are classified according to the stage of application (hot and cold), types, complexity.
Hot blow molding decoration carried out by applying glass cakes, colored chips, ribbons, twisted and tangled threads, colored spots. The "crackle" cut is used - a network of small surface cracks formed when the set is rapidly cooled in water or in wet sawdust. Using special techniques, a pattern of air bubbles, ribbons, threads is created in the thickness of the glass. A groove "for a roll" is used, which creates an optical effect due to a wavy inner surface formed when blowing a preform in a ribbed shape. Iridescent films (iridescence) on the surface of products can be obtained by the deposition of salts of tin chloride, barium, etc. on a hot product; these salts, decomposing, form transparent, shiny iridescent films of metal oxides. Peculiar patterns of different colors and transparency are obtained using zinc sulfide glass.
Decorating blown products in a hot state is labor-intensive, but it perfectly reveals the properties of glass, gives the products uniqueness and originality.
Pressed products are decorated mainly due to the pattern from the mold.
Decoration of products in a cold state carried out by means of mechanical treatment (figured grinding), chemical treatment (etching) and surface decoration using silicate paints, gold preparations, chandeliers.
Mechanically applied cuts include matte tape, numbered grinding, diamond edge, flat edge, engraving, sandblasting.
Matte tape- This is a strip 4-5 mm wide. Numbered grinding - a matte surface pattern made of round, oval sections or notches.
Diamond edge- This is a pattern of deep two-sided grooves, which, when combined with each other, form bushes, nets, polygonal stones, simple and multi-rayed stars and other elements. The pattern is applied on manual or automatic machines using an abrasive wheel with a different edge profile. After cutting the pattern, it is polished to full transparency. The diamond edge is especially effective on crystal items, where the brilliance and play of light in the edges are well revealed.
Flat edge- these are polished planes of various widths along the contour of the products.
Engraving- surface matte or less often a light pattern of a predominantly vegetative character with a careful study of details.
Sandblasting - a matte pattern of various textures, formed when processing glass with sand, which is supplied under pressure to the cutouts of the stencil.
Etching cuttings are subdivided into simple (helioshirny) etching, complex (pantographic), and deep (artistic) etching. To obtain a pattern, the product is covered with a layer of protective mastic, on which a pattern is applied with machine needles or manually, exposing the glass. Then the dishes are immersed in a bath with a mixture of hydrofluoric and sulfuric acids, which dissolve the glass along the nude pattern to different depths.
Simple, or heliosphere, etching- this is an in-depth transparent geometric pattern in the form of straight lines, curves, broken lines.
Complex, or pantograph, etching is a linear in-depth drawing, but of a more complex, often vegetative character.
Deep, or artistic, etching- This is a relief drawing of a mainly vegetative subject on two-layer glass. Due to the different etching depth of colored glass, a convex pattern of different color intensity is formed. Cutting is very laborious.
Surface decorationsilicate paints, gold preparations, chandeliers - this is painting, application of ribbons (width 4-10 mm), layering (1-3 mm), antennae (up to 1 mm), decals (decalcomania), photographic images and etc. Drawings are fixed by firing at a temperature of 550-600 ° C.
New methods of decoration are being developed - plasma spraying of metals, glass powders, photochemical engraving, etc.
The production process ends with acceptance control and product labeling. Blown, press-blown products are marked by sticking a paper label indicating the plant's trademark, standard number, grade (crystal blown), cutting group, price. Pressed products are marked with an imprint of the necessary data on the bottom of the products during molding.
2 Nomenclature of consumer properties of glassware2.1 Basic consumer properties of glassware
The consumer properties of glass products determine the possibility of their intended use, convenience and reliability in operation, beauty and artistic expressiveness. They depend on the perfection of the author's design, the properties of the glass and the quality of the workmanship.
The main consumer properties of glass household products are functional, ergonomic, aesthetic and reliability properties.
Functionalthe properties of glassware provide for the possibility of performing two main functions: "accept" and preserve food and drinks in the same quantity and quality and "give" them in whole or in part as needed. These properties depend on the nature of the glass, the shape, size and purpose of the products, the characteristics of food and drinks. All these factors determine the variation in the shape and size of products.
The ability to "accept" and preserve food and drinks is determined by the following group indicators: chemical resistance to food and drinks, resistance to weathering, resistance to heat, resistance to mechanical stress. Ability to "give away" food and drinks: functionality of volumetric-spatial solution and versatility.
Ergonomicproperties predetermine, first of all, convenience (comfort) of use and hygiene of glassware. The comfort of household utensils is determined by the convenience of holding, carrying, performing the functions of storage, washing, as well as the convenience of transportation and storage. Hygienic properties are primarily due to the nature and properties of glass and are characterized by such group indicators as harmlessness and contamination.
Aestheticthe properties of glass household goods are determined by the integrity of the composition, the rationality of the form and the information content.
The integrity of the composition characterizes the arrangement, addition and connection of parts into a single whole in a certain order. It is due to the spatially decorative structure, tectonics, proportions of the shape of glassware.
The rationality of the form characterizes the conformity of the form of the product to the functional purpose and environmental conditions, the conformity of the tonal and color solution of individual elements to the requirements of ergonomics, the style solution - to the interior, manufacturing technology - to the properties of the material.
The information content of glassware is determined by the symbolism, originality and compliance with their style and fashion prevailing at a given time.
Reliability property glass products are determined by their durability and preservation. Of greatest importance is durability, which is characterized by physical and moral wear and tear.
The nomenclature of the main consumer properties of glassware is presented in Appendix A.
2.2 Physical and chemical properties of glass
Indicators of a number of consumer properties of glassware are indicators of the physical and chemical properties of glass.
The most important of these are the following:
Density of glass varies from 2.2 g / cm 3 for quartz glass to 3.0 g / cm 3 and more for high-lead crystal. It depends mainly on the presence of heavy metal oxides (lead, barium, zinc) in the glass composition and affects the weight of products, optical and thermal properties. With an increase in density, the refractive index of light, brilliance and play of light in the edges increase, but heat resistance, strength and hardness decrease.
The mechanical properties of glass are characterized by the absence of plastic deformation, high compressive strength (500-800 MPa) and low strength in tension, bending (25-100 MPa), and especially upon impact (15-20 MPa). Strength depends on the chemical composition: it increases from the presence of SiO 2, Al 2 O s, B 2 O s, MgO in the glass composition and decreases from the presence of alkali oxides, PbO. However, the decisive influence is exerted by the internal structure of the glass, the state of the surface, and the presence of defects on it. Strength is increased by quenching, ion exchange in molten salts, applying metal oxide coatings to the surface, and by other methods.
The thermal properties of glass are characterized by a very low thermal conductivity, significant heat capacity and thermal expansion. The thermal stability of products increases with an increase in the mechanical strength of glass, thermal conductivity and with a decrease in thermal expansion and heat capacity. The measure of heat resistance is the temperature difference that the product can withstand without destruction. The heat resistance of quartz glass is 1000 ° С, glassware made of high-quality glass - 95 °, glassware made of sitalls - 300-600 ° С.
All methods that increase mechanical strength simultaneously improve heat resistance.
Optical properties of glass varied. Glasses can be transparent (transmittance 0.85 and more) and dimmed to varying degrees, colorless and tinted, with a shiny and matte surface. Optical characteristics of glasses - refractive indices and average dispersion, reflection and transmission coefficients; color indicators largely determine the aesthetic merits of the dishes. The ability of glass to perceive colors, which enhance the emotional expressiveness of products, is especially important.
The chemical resistance of glass determines the purpose and reliability of products. It is very high, especially in relation to water, organic and mineral acids (except for hydrofluoric). Alkalis and alkali carbonates are more aggressive. Hydrofluoric acid dissolves glass and is therefore used for drawing patterns on glass, matting and chemical polishing of products.
In terms of water resistance, glass is divided into five hydrolytic classes: the first class is glass that cannot be changed by water, the fifth is unsatisfactory.
Conclusion
The development of glass production is one of the constituent factors of the development of the economy of our country. For the manufacture of household utensils and decorative products, oxide glasses are used, in which the main glass-formers are oxides of silicon, boron, aluminum, etc. The production of glass products consists of processing raw materials, compiling a charge, melting glass, molding and annealing products, their primary and decorative processing.
Consumer properties and the main features of the range of glass products are formed at the design and construction stage when creating prototypes and in the process of serial production. When developing new products, the artist takes into account the conditions of their operation, the method of forming, the need to ensure ease of use and durability of products, the requirements of the artistic style and fashion. Based on this, the composition and color of glass, the configuration of products in general and in details, wall thickness, decoration method, etc. are determined.
The consumer properties of glass products determine the possibility of their intended use, convenience and reliability in operation, beauty and artistic expressiveness. They depend on the perfection of the author's design, the properties of the glass and the quality of the workmanship. Indicators of a number of consumer properties of products are indicators of physical and chemical properties of glass.
The prototype must be accurately reproduced in serial (mass) production. The quality of its reproduction, that is, the quality of the manufacture of products, depends on the observance of the production technology.
According to GOST 4.75—82 “Sorted glassware. Nomenclature of indicators "to consumer properties and their indicators include the following:
Indicators of purpose - chemical composition and density of glass, shape and main dimensions of products, their stability on a flat surface;
Reliability indicators - impact strength, hardness, heat resistance, water resistance, fastening strength of parts, indicators of annealing quality;
Indicators of ergonomic properties - the content of harmful substances;
Indicators of aesthetic properties - fidelity of reproduction of the author's sample, indicators of compositional integrity, information expressiveness, perfection of manufacturing of products, as well as refractive indices, average dispersion, light transmission, beading angle;
Functional properties. Glass is a material that is widely used for contact with foodstuffs, its thermal resistance is significantly increased as a result of tempering. The chemical resistance of crystal is lower than that of other types of glass; therefore, it is not recommended to store food products in this container for a long time. Ergonomic properties. The convenience of performing the main and additional functions of glassware depends on the design features of the products, their shape and size. Glass has a smooth surface, which improves ease of care, but embossed and surface decorations applied to products can reduce this indicator.
Security properties glassware is determined by chemical and mechanical safety. Chemical absence is determined by the type of glass, the type and location of the decor. When characterizing mechanical bez-ty, it should be borne in mind that when glass breaks, fragments with cutting edges can form.
Reliability glass products are determined by mechanical, thermal, and chemical resistance. These indicators are influenced by the type of glass, wall thickness of the product, type of decoration, design features.
29. Plastics based on polymerization polymers: types, properties, applications.
These are materials that are obtained by synthesizing polymers with various ingredients. In def. conv. plastics can be molded into products and retain their shape. The composition of plastics includes fillers, colorants, plasticizers, stabilizers and other additives.
Types (+ properties and application):
Polyethylene- in a thin layer, transparent, can be translucent, painted in different colors, resistant to impacts, bends, frost-resistant. It looks and feels like paraffin wax. Disadvantages: under the influence of sunlight, it ages quickly, gives an unpleasant aftertaste to fatty foods. Polyethylene is used for manufacturing pipes, film materials, dishes, etc..
Polypropylene- similar in appearance to polyethylene, characterized by high heat resistance (170 ° C), mechanically exchangeable, resistant to pollution, tendency to aging, low frost resistance. Polypropylene is used for manufacturing buckets, thermoses, flasks, fibers and threads, pipes, haberdashery, etc.
Polyvinyl chloride (PVC)- translucent or transparent, resistant to abrasion, chemically resistant, mechanically strong. Produced rigid (without plasticizer) - vinyl plastic (plates, pipes, sheets, haberdashery), as well as soft, elastic (with a plasticizer) - plastic compound ( hoses, pipes, films, linoleum, tablecloths, etc.). Based on polyvinyl chloride, get foam and cellular plastics used for packaging and thermal insulation of furniture, refrigerators, televisions, etc. Perchlorovinyl is obtained from chlorinated polyvinyl chloride, which is used to obtain glues, varnishes, enamels, and chlorin fibers.
Polystyrene- transparent, colorless. or painted in bright colors, chemically resistant, emits a metallic sound upon impact. The use of polystyrene is limited due to toxicity. It is applied for haberdashery goods, for radio components, fountain pen cases, etc.
Polymethyl methacrylate (plexiglass)- transparent, can be colored, has a high translucency, transmits ultraviolet rays, heat resistance over 100 ° C, resistant to aging, non-toxic. It is used for manufacturing haberdashery, fibers, dishes, varnishes, enamels, school and office supplies, glasses for instruments and watches.
Fluoroplastics- fluoroplastic (Teflon) is widely used with a surface that is oily to the touch, chemically resistant, strong, flexible, elastic, and has high heat resistance. Made of fluoroplastic machine parts, fiber (fluorlon), inner covers of pots, pans and other steam.
30. Plastics based on polycondensation polymers: types, properties, applications.
Plastics (plastics) are materials that are obtained by synthesizing polymers with various ingredients. Under certain conditions, plastics can be molded into products and retain their shape. The composition of plastics includes fillers, colorants, plasticizers, stabilizers and other additives.
Types (properties, application):
Phenoplasts- mechanically strong, solid, heat-resistant, have electrical insulating properties. Products made of phenolic plastics are dyed black and brown. Phenolic plastics release toxic phenol when exposed to hot water. Used for manufacturing wiring and haberdashery products.
Aminoplasts are characterized by mechanical strength, chemical resistance, electrical insulating properties, do not soften when heated. Under the influence of hot water, aminoplasts release formaldehyde, a toxic substance. Aminoplast dishes are made only for cold food. Aminoplasts are used to produce wiring products, adhesives, laminated plastics and other household products.
Polyamides (nylon)- painted in different colors, solid, can be elastic, melt at a temperature of 180-250 ° C, resistant to abrasion, chemically resistant to alkalis and organic solvents. They produce household products, synthetic bristles for brushes, films, synthetic fibers, etc.
Ester plastics(alkyd resins, lavsan, etc.).
Alkyd resins- glyphthalic, pentaphthalic resins - used to obtain glues, varnishes, enamel paints.
Lavsan (polyethylene terephthalate) - from it get fibers, films, film bases, etc.
Polyurethanes have high abrasion and chemical resistance. They are used in production shoe materials - heels, soles; adhesives, varnishes, in the form of foam rubber - for seats in upholstered furniture, etc.
31. Household cleaning machines: classification and group characteristics of the assortment, design features, types, quality indicators.
Vacuum cleaners carry out vacuum dusting of premises. The principle of operation is based on the use of the energy of a moving air stream. The air flow created by the vacuum cleaner captures dust, fine debris and transfers them to the filter, where they are deposited, and the purified air is thrown into the room.
The vacuum cleaner consists of a body, an air intake unit, a filter, a flexible hose, a set of nozzles for various purposes and devices that increase the convenience of using the machine. Nozzles for their intended purpose are carpet, clothing, for cleaning the floor, hard-to-reach places, etc.
Classification:
1. by appointment - for dry cleaning, detergents.
2. by design features - with a dust bag, container type, with a liquid filter.
Glasses are classified according to their composition. Their name depends on the content of certain oxides.
The following oxide glasses are distinguished:
Silicate - SiO 2;
Aluminosilicate - Al 2 O 3, SiO 2;
Borosilicate - B 2 O 3, SiO 2;
Boroaluminosilicate - B 2 O 3, Al 2 O 3, SiO 2 and others.
Each type of glass has certain properties.
Silicate glasses are subdivided into ordinary, crystal, heat-resistant. Ordinary include lime-sodium, lime-potassium, lime-sodium-potassium glasses.
Crystal glasses are characterized by increased luster and strong refraction. Distinguish between lead and lead-free crystal. Lead crystal has an increased weight and is well decorated.
Depending on the amount of lead oxide, lead crystal is divided into:
1. Crystal glass containing lead, boron or zinc oxide in an amount of at least 10%.
2. Low-lead crystal containing 18-24% lead oxide.
3. Lead crystal containing 24-30% lead oxide.
4. High-lead crystal containing 30% or more lead oxide.
Lead-free crystal contains mainly barium oxide (at least 18%), which improves the refraction, increases the hardness and shine of the glass, but reduces the transparency.
Heat-resistant glass can withstand sudden temperature changes. They include boron compounds (12-13%). The thermal resistance of such glass increases after tempering.
Chemical properties of glass.
The chemical resistance of glass determines the purpose and reliability of products. It is very high, especially in relation to water, organic and mineral acids (except for hydrofluoric). Alkalis and alkali carbonates are more aggressive. Hydrofluoric acid dissolves glass and is therefore used for patterning, matting and chemical polishing of products.
The formation of consumer properties of glass products occurs in the process of their production.
Glass goods manufacturing consists of a number of stages: preparation of raw materials, preparation of a charge, melting of glass, production of glass products, processing and decoration of products, sorting, marking and packaging of products.
1. Preparation of raw materials comes down to cleaning quartz sand and other components from unwanted impurities, fine grinding and sieving materials.
2. Preparation of a charge, that is, a dry mixture of materials, consists in weighing the components according to the recipe and thoroughly mixing them until they are completely homogeneous. A more progressive method is the production of briquettes and granules from a charge; at the same time, the homogeneity of the charge is maintained, and cooking is accelerated. In addition, to speed up the melting of glass, 25-30% of glass breakage is added to the charge. The cullet is washed, crushed and passed through a magnet.
3. Cooking of molten glass from the charge is carried out in baths and pot furnaces at a maximum temperature of 1450-1550 ° C. During the cooking process, complex physical and chemical transformations and interactions of raw materials take place. With the help of clarifiers, the glass mass is freed from gas inclusions, thoroughly mixed until uniformity in composition and viscosity is achieved. In case of violations of the modes of processing of raw materials, preparation of a charge and cooking, defects in the molten glass are formed (we will analyze it later).
4. Shaping of articles from a viscous glass mass is carried out by various methods. The molding method largely determines the configuration of products, wall thickness, decoration techniques, coloring and therefore is an important assortment feature and price-determining factor.
Household products are made by blowing, pressing, pressing blowing, bending (bending), casting, etc.
Blowing out - the oldest method of molding glass products. Blowing can be mechanized, vacuum blowing, manual in molds and guten (free).
Manual blowing is carried out using a glass blowing tube. This blowing can be done in molds or without molds. By blowing in molds, products of any configuration and wall thickness with a smooth and shiny surface are obtained. They produce colorless, mass-dyed and overhead products (two- and multi-layer).
Blowing without a shape or free blowing (in the trade - Guten molding) is also carried out by means of a glass blowing tube, but the products are molded and finally finished mainly in air. Products are characterized by the complexity of shapes, smooth transitions of parts, a thickened wall.
Colorless products of simple shapes, mainly glasses, are produced by mechanized blowing on automatic machines.
Blown products have the smoothest walls, strong gloss, great transparency, the most varied shapes and wall thicknesses. They are decorated in almost every possible way and are considered to be of the highest quality.
Pressing are the most widespread and economical methods of obtaining glass products. Products are molded on automatic and semi-automatic presses in special molds, where a pattern is immediately applied to them. They are characterized by a large wall thickness (more than 3 mm), a large mass, less transparency and heat resistance, a significant bottom thickness, traces of the form are visible. The pressed dishes have simple shapes with a wide top.
They try to overcome some monotony of pressed products by creating a light relief pattern on the surface (textured press), pressing without an upper ring, which makes it possible to obtain a freely formed edge for each product, a combination of pressing and bending (press bending).
Press blowing characterized by the fact that the molding of products takes place in two stages - first they are molded in a mold, and then - in a hot form with air. Products have a narrow neck, thick uneven walls and traces of shape. Press blowing produces cans, bottles, decanters, vials; Products obtained by this method differ from pressed ones in a more complex shape, and from blown ones in thick walls, traces from the shape and a coarser pattern.
Casting. Glass mass is poured into a special mold, where it is cooled and takes shape. This method is used to obtain artistic and decorative items.
Centrifugal casting carried out in rotating metal molds under the action of centrifugal forces. Products obtained by this method have a large mass, and large-sized products are finished by hand. Aquariums are examples of centrifugally cast products.
Other molding methods are less common.
If molded incorrectly, various defects may occur.
Annealing products. During molding, due to the low thermal conductivity of glass, sharp and uneven cooling, residual stresses arise in the products, which can cause their spontaneous destruction. Therefore, annealing is required — heat treatment, which consists in heating the products to 530-550 ° C, holding them at this temperature, and then slowly cooling them. During annealing, residual stresses are weakened to a safe value and are evenly distributed over the cross section of the products. The thermal resistance of the glass depends on the quality of the annealing.
Processing and decoration. Primary processing consists in processing the edge and bottom of the products, lapping the corks to the neck of the decanters. Decorative processing is the application of jewelry of a different nature to products. Decor determines the aesthetic properties of glass products and is one of the main pricing factors.
Cuttings are classified according to the stage of application (hot and cold), types, complexity.
Hot applied jewelry:
1. Colored glass is obtained by adding dyes to the glass mass.
2. Products with bloom are made from 1 layer of glass and cover it with 1 or 2 layers of intensely colored glass.
3. Decorating hot blown products is carried out by applying glass adhesions, ribbons, twisted and tangled threads. Variety - decoration with filigree or thread has the form of 2 or 3 colored spiral threads.
4. Adornment for marble or malachite is obtained in the process of melting milk glass with the addition of ground, unmixed colored glass.
5. Cutting "crackle" ("frosty", "frosty glass") - a network of small surface cracks formed during rapid cooling of the product in water. Next, the semi-finished product is placed in an oven, where the cracks are melted.
6. Use a groove "for a roll", which creates an optical effect due to the wavy inner surface formed when the preform is blown in a ribbed shape.
7. Decorations with colored bulk. The heated billet is rolled over crushed colored glass, which is melted to the surface.
8. Iridescent films (irrigation) on the surface of products can be obtained by the deposition of salts of tin chloride, barium, etc on a hot product; These salts, decomposing, form transparent, shiny iridescent films of metal oxides (resembling mother-of-pearl).
9. Decorations by the method of free blowing - the product takes on a peculiar and unique shape.
10. Chandeliers - application of metal solutions to the surface of the product. Then the product is annealed, the solvent evaporates, and the metal film is fixed on the surface.
11. Pressed products are decorated mainly by the design from the mold.
Decoration of products in a cold state carried out by means of mechanical treatment, chemical treatment (etching) and surface decoration using silicate paints, gold preparations, chandeliers.
Mechanically applied cuts include matte tape, numbered grinding, diamond edge, flat edge, engraving, sandblasting.
1. Matte tape is a strip 4-5 mm wide. A metal strip is pressed against the surface of the product during its rotation, under which sand and water are fed. At the same time, grains of sand scratch the glass.
2. Numbered grinding - a matte surface (shallow) pattern made of round, oval sections or notches. Applied with emery wheels.
3. A diamond facet is a pattern of deep two-sided grooves, which, when combined with each other, form bushes, nets, polygonal stones, simple and multi-rayed stars and other elements. The pattern is applied on manual or automatic machines using an abrasive wheel with a different edge profile. After cutting the pattern, it is polished to full transparency. The diamond edge is especially effective on crystal items, where the brilliance and play of light in the edges are well revealed.
4. Flat face - these are polished planes of various widths along the contour of the product.
5. Engraving - surface matte or, less often, light pattern of a predominantly vegetative nature without large depressions. It is obtained using rotating copper discs or ultrasound.
6. Sandblasting - a matte pattern of various shapes, formed when glass is processed with sand, which is fed under pressure into the cutouts of the stencil.
Pickling cuts, are subdivided into simple (helioshirny) etching, complex (pantographic), deep (artistic) etching. To obtain a pattern, the products are covered with a layer of protective mastic, on which a pattern is applied with machine needles or manually, exposing the glass. Then the dishes are immersed in a bath of hydrofluoric acid, which dissolves the glass along the nude pattern to different depths.
Simple, or helioshirny, etching is an in-depth transparent geometric pattern in the form of straight, curved, broken lines.
Complex, or pantographic, etching is a linear in-depth pattern, but of a more complex, often vegetable character.
Deep, or artistic, etching is a relief drawing of a mostly vegetative subject on 2 or 3-layer glass. Due to the different etching depth of colored glass, a pattern of different color intensity is formed.
Surface decoration can be carried out with silicate paints, gold preparations. Such decorations include painting, decalcomania (it is a multicolor drawing without brush strokes, applied using decals), silk-screen printing (one-color drawing obtained by stencil using a silk mesh), application of ribbons (4-10 mm wide), layering (1- 3 mm), antennae (up to 1 mm), photographic images, etc. New methods of decoration are being developed - plasma spraying of metals, glass powders, photochemical engraving, etc.
The production process ends with acceptance control and product labeling.
Glass products, in accordance with their purpose, are divided into three classes: household, architectural and construction and technical.
The range of household products is classified according to many criteria:
1. According to their purpose, household glass products are divided into 5 groups: household utensils, art products, household utensils, kitchen utensils, lamp products.
2. According to the composition of glass, products are distinguished from sodium - calcium - silicate, special household, crystal glass, etc.
3. By the method of molding, blown, extruded, press-blown products are distinguished, as well as those obtained by centrifugal casting.
4. By the color of the product can be colorless, colored and tinted.
5. According to the size, the products are divided into small, medium, large and extra large. The size of the products is characterized by their diameter, length or height, and the size of the hollow products is characterized by their capacity.
6. In terms of completeness, household glass products can be piece and complete.
7. By the method of applying jewelry (see earlier).
Modern trends in the decoration of glassware - an expansion of the range of colored glasses, a combination of colored and slightly dimmed glass in an overlay, contrasting combinations of elements of a diamond facet, matte engraving, a chandelier, a wide use of decal and silk-screen prints of various subjects, picturesque cuts with paints and gold, often in combination with matting. Gutted cuts and products are still popular.
8. According to the style, the products are subdivided taking into account the shape of the body (ball, oval, cone, etc.), the presence of adhered (handle, leg, lid holder) and removable (cork, lid) parts, the nature of the edge (smooth, cut) and the bottom of the products. ...
The dishes are produced with a bottom of normal thickness, thickened, as well as on a pallet (a ledge or ledge in the lower part of the product).
The leg of the products can be of different heights, shapes (straight or curly) and processing (faceted and even). The style, along with the aesthetic features of molten glass and cutting, largely determines the artistic expressiveness of products. It is subject to change according to style requirements.
Assortment of glassware
The assortment of glassware, depending on the method of production and purpose, is divided into the following groups: blown products, pressed products, press-blown products, crystal products, household dishes, kitchen utensils.
The range of blown ware is very wide. These are glasses, goblets, wine glasses, wine glasses, wine glasses, jugs, decanters, sugar bowls, oil cans, vases for table setting (for fruits, jam, cookies, cream, sweets, salad bowls), dishes, etc.
The assortment of pressed cookware is much narrower. These are saucers for jam, trays, vases, lemon squeezers, glasses, sugar bowls, wine glasses, salad bowls, sugar bowls, etc.
Press blown ware has a limited range. These are decanters of various styles and containers, oil cans, table pans, etc.
Household utensils include products used for storing and preserving food (thermoses, jars, jars for pickles and jams, barrels, bottles for storing liquids).
Cookware made of heat-resistant glass is represented by pots of various capacities, baking dishes, braziers, pans. Heat-resistant glasses (borosilicate glasses) are used to make utensils for cooking on an open fire or in microwave ovens. Such dishes are obtained by pressing. Borosilicate glass products are subjected to special treatment-hardening to increase thermal resistance and are not decorated. Hardening consists in heating products to 700 ° C and subsequent rapid and uniform cooling by blowing air. In this case, high, evenly distributed residual stresses arise in the glass, increasing the impact strength by 5-8 times, and heat resistance by 2-3 times.
Crystal products. They are obtained mainly by blowing and press blowing methods. The range of blown crystal products is close to blown glassware. They produce crystal products, both piece and complete.
Assortment of decorative items- a glass sculpture, flower vases, toiletry, horn-shaped glasses, dishes, etc. Each type of product is produced in several varieties (articles), differing in size and style.
Range of lamp products consists of table lamps, lamp tanks, lamp glasses.
The main consumer properties of glass household products are functional, ergonomic, aesthetic and reliability properties.
The functional properties of glassware (for example, plysuda) provide for the ability to perform two main functions: "accept" and keep food and drinks in the same quantity and quality, and "give" them in whole or in part as needed. These properties depend on the composition of the glass, the shape, size and purpose of the products, the characteristics of food and drinks.
The ability to "accept" and preserve food and drinks is determined by the following group indicators: chemical resistance to food and drinks, resistance to weathering, resistance to heat, resistance to mechanical stress. Ability to "give away" food and drinks: functionality of the volumetric solution and versatility.
Ergonomic properties predetermine convenience first of all
(comfort) use and hygiene of glassware. The comfort of household utensils is determined by the convenience of holding, carrying, performing the functions of storage, washing, as well as the convenience of transportation and storage.
Hygienic properties are primarily due to the nature and properties of glass and are characterized by such group indicators as harmlessness and contamination.
The aesthetic properties of glass household goods are determined by the integrity of the composition, rationality of form and information content.
The integrity of the composition characterizes the arrangement, addition and connection of parts into a single whole in a certain order. The rationality of the form characterizes the conformity of the form of the product to the functional purpose and environmental conditions, the conformity of the tonal and color solutions of individual elements to the requirements of ergonomics, the style solution - to the interior, manufacturing technology - to the properties of the material.
The information content of glassware is determined by the symbolism, originality and compliance with their style and fashion prevailing at a given time.
The property of reliability of glass products is determined by their durability and preservation. Of greatest importance is durability, which is characterized by physical and moral wear and tear.
Indicators of a number of consumer properties of products are indicators of the physical and chemical properties of glass.
According to GOST 4.75—82 “Sorted glassware. Nomenclature of indicators "to consumer properties and their indicators include the following:
Indicators of purpose - chemical composition and density of glass, shape and main dimensions of products, their stability on a flat surface;
Reliability indicators - impact strength, hardness, heat resistance, water resistance, fastening strength of parts, indicators of annealing quality;
Indicators of ergonomic properties - content of harmful substances;
Indicators of aesthetic properties - the accuracy of reproduction of the author's sample, indicators of compositional integrity, information expressiveness, perfection of manufacturing products, as well as refractive indices, average dispersion, light transmission, cutting angle;
Economic indicators - weight of products (consumption of raw materials), cost.
Quality assessment and quality requirements for glass products.
The quality of glassware and decorative glassware must comply with the requirements of GOST 30407-96 “Crockery and decorative glassware. OTU. " Quality assessment is carried out by organoleptic (assessment of appearance) and physicochemical methods (determination of dimensions, thermal stability, etc.). In terms of structural and dimensional features, household glassware must comply with the approved samples. The product should not sway on a flat horizontal surface. Items in contact with hot food (glasses and saucers for tea, plates for hot food, etc.) must be thermally stable. Blown products should not collapse at temperature drops of 95-70-20C, pressed - at 95-60-20C.
Not allowed on products: chips; cut edges; adhering pieces of glass; cutting and crumbling glass particles when decorating products in bulk; through cuts; foreign inclusions with cracks and notches around them. The end surface of the top edge and the seams of the products must be smooth. The decorative coating applied to the inner surface of products in contact with food must be acid resistant.
The fastening of the handles of products and decorative elements must be durable. The permissible migration of harmful substances emitted from glass products in contact with food is established by the State Sanitary and Epidemiological Supervision authorities in the relevant regulatory documents approved in the prescribed manner.
Defects of glass products are divided into defects in molten glass, production and processing.
To defects in molten glass include:
1. Gas inclusions (“midge” diameter is more than 0.8 mm and “bubble” diameter is less than 0.8 mm) are formed as a result of insufficient clarification of the molten glass. Cloudy and bursting bubbles in the product are not allowed.
2. Swiles and schlieres are transparent inclusions that differ from the bulk of glass in composition or physical properties. Svili are filamentous inclusions, and schliers are hillocks, nodules, clots of glass.
3. Solid inclusions (stones, crystals). They arise as a result of crystallization of the molten glass.
4. Insufficient discoloration - the result of the presence of metal oxides in the glass.
Workmanship defects:
1. The difference in thickness in the glasses and the bottom of the product is the result of uneven distribution of the molten glass.
2. Chips and gaps;
3. Garbage - small chips;
4. Forging - unevenness in the form of fine waviness of the surface;
5. Wrinkles - irregularities in the form of ripples on the surface;
6. Pocket-shaped folds-unevenness.
Curvature, folds and wrinkles on the products are not allowed.