Requirements for glassware. Coursework: Analysis of the range, competitiveness and quality of glassware. Evaluation of the labeling of glassware from different manufacturers
IN products made of colorless glass, slight color shades are allowed that do not spoil the presentation. A difference in the intensity of coloring of the same product made of colored and overlaid glass, caused by uneven wall thickness, and various color shades of decor obtained by heat treatment of zinc sulfide glass, are allowed without spoiling the presentation.
On the areas of products decorated with colored chips, foreign materials that do not spoil the presentation are allowed. inclusions with a size of not more than 1 mm in an amount of not more than 3 pcs. (for small and medium-sized products), not more than about pcs. (for large and extra large).
For defects that cannot be measured, approval of samples agreed with the consumer is allowed.
Local accumulations of midges, cut edges, adhering pieces of glass, burrs, matte coating on the edges, as well as under-finishing and elongation of pattern lines larger than 4.0 mm are not allowed in the dishes.
The following defects are allowed:
svil, rarely located, not spoiling the presentation;
a bubble in the form of a "sickle", which does not spoil the presentation at the junction of the vessel and the leg, the leg and the bottom, the handle and the vessel, decorative elements:
scree, edge remelting, processed chips and crevices, traces of surface disturbance, traces of molds and scissors that do not spoil the presentation;
traces of distillation and polishing, defects in decorating with preparations of precious metals, luster and silicate paints, underfinishing and elongation of the lines of the pattern when decorating with ring lines, twisting in products of mechanized production that do not spoil the presentation.
In addition, in products with a stem, the asymmetry of the junction of the vessel and the bottom is allowed without spoiling the presentation, and in the places of the fusion of the vessel and the legs, the legs and the bottom, there is also an annular thickening or waviness.
The “mound” on the decorated items must be melted, without cutting glass particles, and must not crumble. The seams and the end surface of the upper edge of the products must be smooth.
Lids and plugs must be matched to products. Lids should freely cover or enter products. Stoppers with an unground stem should freely enter the neck of the product. The lapped stem of the cork should fit snugly against the neck of the product, a barely noticeable swing of the cork in the neck is allowed. In toilet utensils, the stem of the cork should be lapped.
The product must be stable on a flat horizontal surface.
Glasses and saucers for tea, plates for hot food must be thermally stable. Blown products should not collapse at a temperature of 95-70--20°C, pressed 95--60--20°C.
The total number of permissible defects in appearance in one small product is no more than 2, medium - 3, large - 4.
When tapped, crystal products emit a long melodic ringing. The sound effect is enhanced by increasing the lead oxide content and reducing the wall thickness: drop-shaped products have a greater sound effect.
A feature of crystal products is also a light effect, depending on the amount of lead and the angle of cutting. At a faceting angle of 90 degrees, the reflection of the light incident on the facet is greatest. The reflection coefficient is directly proportional to the content of lead oxides in the glass.
Crystal products are made massive and thick-walled, so they can be applied with deep diamond edges and thereby increase the reflection of light.
depending on the quality of the glass. ways of producing and processing products are divided into 1st and 2nd grades. Products must have a shiny smooth surface, polished to full transparency.
In colorless products, slightly pronounced bluish hues are allowed that do not spoil the presentation.
Products made of glass and crystal, subjected to sudden heating and cooling, mechanical stress during operation, must have the necessary thermal resistance and mechanical strength, especially to impact.
Consumer properties (usefulness) of glass products used in everyday life and in the field of public catering are determined by a set of properties - functionality, economy, aesthetics, comfort (convenience, hygiene), reliability (strength, durability), etc.
The functional properties of glass products depend on the nature of the glass, shape, size and purpose of the products.
Ergonomic properties of products, first of all, ease of use (comfort) and hygiene of glass products.
The comfort of household utensils is determined by the convenience of performing its functions, keeping it clean, and storing it. At the same time, the shape and capacity of the product, the presence and location of the handles, and the correspondence of their shape to the fingers are taken into account. Assessing the convenience of caring for products, they pay attention to the diameter of the upper hole, the nature of the surface, the presence of roughness, sharp, cutting and scratching areas, corners and recesses, as well as ease of transportation, packaging, storage of products.
The hygienic properties of dishes are primarily due to the nature and properties of glass. Products must have high chemical resistance, must be harmless to the human body. When assessing hygiene, they take into account the simplicity and ease of removing various kinds of contaminants from the surface of products, keeping them clean.
The aesthetic properties of glass products are characterized by the integrity of the composition, the rationality of the form and information content.
Indefinite contours of both the entire product and its elements, unfortunate color and pattern, hiding natural properties material, impair the aesthetic perception of the shape of the product.
The ratio of the dimensions of the parts, sides, pattern characterizes the proportionality of the product.
The reliability of glass products is determined by their durability. Less reliable are products with attached parts, on a high leg, of complex configuration.
Products must have a shiny smooth surface, polished to full transparency.
The edge and end surface of the upper edge of the products must be melted or polished. Facet is applied to the edge of the upper edge of the products or other types of processing are used. Lids and plugs must be matched to products.
Lids should freely cover or enter products. The difference between the diameter of the cover and the edge of the body (or neck) should not exceed 2 mm.
Stoppers with an unground stem should freely enter the neck of the product. The lapped stem of the cork should fit snugly against the neck of the product. In toilet utensils, the stem of the cork should be lapped.
The spout of the product should be located opposite the handle.
Fixing sticky parts and decorative elements should be simple.
The bottom of the products must be smooth, clearly polished, ensure a stable position on a flat horizontal surface. The inner surface of the bottom of trays and saucers should ensure the stability of the products placed on them.
Products in the set must be selected so that the difference in height between them does not exceed the permissible deviation from the parallelism of the edge of the bottom plane.
The difference in wall edge thickness should not be more than 0.5 mm for products with wall thickness up to 3 mm inclusive and 1 mm for products with wall thickness over 3 mm.
The quality of household glassware depends on the presence of defects that adversely affect its mechanical, thermal, optical, aesthetic and sanitary-hygienic properties.
Defects in glass products are divided into three groups - defects in glass, production and processing.
The impact of a particular defect on the quality of the product depends on its type, location, size, and also on the size of the products.
According to these features, some defects are allowed with restrictions on the number, size and location, while others are not allowed at all.
GOST 30407-96 standardizes the quality of the main groups of glass products. These are physical and chemical indicators, indicators appearance, marking, packaging, safety. When checking the appearance, you should pay attention to indicators that may adversely affect the properties of glassware.
Glass defects:
- Rukh - opaque blotches
- Schlier - transparent droplets and tubercles
- Svil - inclusions in the form of flagella or threads.
- Gas inclusions - bubbles
- Insufficient discoloration
Production defects:
- Different thickness of the edges of the product, its walls or bottom.
- Edge scree - crevices resulting from poor-quality grinding
- Small cracks - cuts
- chipped
- Underpressing - lack of glassware mass
- Forged - occurs when the form for casting is worn out.
Processing defects:
- Sticky glass pieces
- Edge deformation, strong melting - overheating
- Asymmetrically arranged parts
- oblique edge
- Erased or matte gold pattern
Glassware intended for drinking and eating is subject to mandatory certification.
Cookware safety requirements:
- Chemical Safety - Lead and Cadmium Restrictions
- Mechanical safety - no manufacturing and processing defects
- High and low temperature resistance
- Ability to hold water
- Strong fixture of elements of ware and its details.
When checking glassware in operation, it is placed on a stable horizontal surface, previously filled with water - to determine the integrity. The lid must fit snugly against the product. The cork should be tightly ground to the neck.
The correctness of the marking includes the name of the manufacturer or his trademark. Article designation and GOST.
The container in which the glassware is packed must be sufficiently reliable. To ensure safety when transporting dishes. It should have a "Caution - glass" sign on it. Other requirements are specified in the contract or agreement.
Consumer properties and quality indicators of glass goods
Classification and characteristics of the range of glass products.
glass classification.
Glasses are classified based on 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;
boron aluminosilicate - B 2 O 3, Al 2 O 3, SiO 2 and others.
Each type of glass has certain properties.
Silicate glasses are divided into ordinary, crystal, heat-resistant. Common ones include soda-lime, soda-lime, potassium-lime, soda-potassium lime glasses.
Crystal glasses are characterized by increased brilliance and strong refraction. Distinguish between lead and lead-free crystal. Lead crystal has an increased mass and is well decorated. Given the dependence on the amount of lead oxide, lead crystal is divided into
1. Crystal glass containing at least 10% lead, boron or zinc oxide.
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 refraction, increases the hardness and brilliance of glass, but reduces transparency.
Heat-resistant glasses withstand sudden changes in temperature.
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They include boron compounds (12-13%). The thermal stability 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 hydrofluoric). Alkalis and alkali carbonates act more aggressively. Hydrofluoric acid dissolves glass and, therefore, is used for applying patterns to glass, matting and chemical polishing of products.
The formation of consumer properties of glass products occurs in the process of their production.
Production of glass goods consists of a number of stages: preparation of raw materials, blending, glass melting, glass production, processing and decoration of products, sorting, marking and packaging of products.
1. The preparation of raw materials is reduced to the purification of quartz sand and other components from unwanted impurities, fine grinding and screening of materials.
2. The preparation of the charge, i.e., a dry mixture of materials, consists in weighing the components according to the recipe and thoroughly mixing them until completely homogeneous. A more advanced method is the production of briquettes and granules from the 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 cullet is added to the mixture. Cullet is washed, crushed and passed through a magnet.
3. Cooking glass melt 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 occur. With the help of clarifiers, the glass mass is freed from gas inclusions, thoroughly mixed until a uniform composition and viscosity is achieved. In case of violations of the modes of processing raw materials, preparation of the mixture and cooking, defects in the glass mass are formed (we will analyze later).
4. The molding of products from viscous glass mass is carried out by various methods. The molding method largely determines the configuration of products, wall thickness, decoration techniques, coloring and, in this regard, is an important assortment feature and pricing factor.
Household products are made by blowing, pressing, pressing blowing, bending (bending), casting, etc.
Blowing - the oldest method of molding glass products. Blowing must be mechanized, vacuum-blown, manual in molds and gooten (free).
Manual blowing is carried out using a glass blowing tube. Such blowing can be carried out in molds and 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-layered).
Blowing without a mold or free blowing (in the trade - Gooten 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 forms, smooth transitions of parts, thickened wall.
By mechanized blowing on automatic machines, colorless products of simple outlines, mainly glasses, are produced.
Blown products have the smoothest walls, strong gloss, high transparency, the most diverse shape and wall thickness. Οʜᴎ are decorated with almost all possible ways and are considered to be of the highest quality.
Pressing are the most widespread and economical methods of obtaining glass products. Products are formed 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 shape are visible. Pressed utensils have simple shapes with a wide top.
They strive to overcome the non-uniformity of pressed products by creating a light relief pattern on the surface (textured press), pressing without an upper ring, which allows to obtain a freely formed edge different for each product, a combination of pressing and bending (press bending).
Pressblowing characterized by the fact that the molding of products takes place in two stages - first they are molded in a mold, and then in hot air. Products have a narrow neck, thick uneven walls and traces of the shape. Press blowing produces jars, bottles, carafes, vials; Products obtained by this method differ from pressed ones in a more complex shape, and from blown ones, in thick walls, traces of the shape and a rougher pattern.
Casting. The glass mass is poured into a special mold, where it cools and takes on the shape of the mold. This method is used to obtain artistic and decorative products.
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 manually. Aquariums can serve as an example of products made by centrifugal casting.
Other molding methods are less common.
Incorrect molding may cause various defects.
5. Annealing products. During molding, due to the low thermal conductivity of glass, sharp and uneven cooling, residual stresses arise in products that can cause their spontaneous destruction. For this reason, annealing is required - heat treatment, which consists in heating the products to 530-550 ° C, keeping 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. The thermal stability of glass depends on the quality of annealing.
6. Processing and decoration. Primary processing consists in processing the edge and bottom of the products, grinding the corks to the throat of decanters. Decorative processing is the application of decorations 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 decorations:
1. Colored glass is obtained by adding dyes to glass mass.
2. Colored products are made from 1 layer of glass and coated with 1 or 2 layers of intensely colored glass.
3. Decoration of blown products in a hot state is carried out by applying glass moldings, ribbons, twisted and tangled threads. Variety - decoration with filigree or twisting has the form of 2 or 3-colored spiral threads.
4. Marble or malachite decoration is obtained in the process of melting milk glass with the addition of ground, unmixed colored glass.
5. Cutting ʼʼcrackleʼʼ (ʼʼfrostʼʼ, ʼʼfrosty glassʼʼ) - a network of small surface cracks that form when the product is quickly cooled in water. Next, the semi-finished product is placed in a furnace, where the cracks are melted.
6. Cut-out “under the roller” is used, creating an optical effect due to the wavy inner surface formed when the billet is blown in a ribbed shape.
7. Jewelry in bulk. The heated workpiece is rolled over crushed colored glass, ĸᴏᴛᴏᴩᴏᴇ is melted to the surface.
8. Iridescent films (irrization) on the surface of products can be obtained when salts of tin chloride, barium, etc. are deposited on a hot product; these salts, decomposing, form transparent, shiny, iridescent films of metal oxides (reminiscent of mother-of-pearl).
9. Jewelry by free blowing - the product acquires a peculiar and unique shape.
10. Chandeliers - application of metal solutions to the surface of the product. Next, the product is annealed, the solvent evaporates, and the metal film is fixed on the surface.
11. Pressed products are decorated mainly due to the pattern from the mold.
Cold decoration carried out by mechanical treatment, chemical treatment (etching) and surface decoration using silicate paints, gold preparations, chandeliers.
To the sections applied mechanically, include matte tape, numbered grinding, diamond cutting, flat cutting, 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. In this case, the grains of sand scratch the glass.
2. Number grinding - matte surface (shallow) pattern of round, oval sections or notches. Applied with emery wheels.
3. The diamond face is a pattern of deep dihedral grooves, which, combined with each other, form bushes, nets, polygonal stones, simple and multi-beam 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 facet is especially effective on crystal products, where the brilliance and play of light in the facets are well revealed.
4. Flat edge - these are polished planes of various widths along the contour of the products.
5. Engraving - a surface matte or less often light drawing of a predominantly vegetative nature without large depressions. It is obtained using rotating copper disks or ultrasound.
6. Sandblasting - a matte pattern of various shapes, formed during the processing of glass with sand, which is fed under pressure into the cutouts of the stencil.
Cuts applied by etching, subdivided into simple (heliospheric), complex (pantograph), deep (artistic) etching. To obtain a pattern, products are covered with a layer of protective mastic, on which a pattern is applied with machine needles or manually, exposing the glass. Next, the dishes are immersed in a bath of hydrofluoric acid, which dissolves the glass in a naked pattern to various depths.
Simple, or heliospheric, 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 vegetative nature.
Deep, or artistic, etching is a relief pattern in the main plant plot on 2 or 3-layer glass. Due to the different depth of etching 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 multi-color drawing without brush strokes, applied with the help of decals), silk-screen printing (a single-color drawing obtained by stenciling using a silk mesh), applying ribbons (4-10 mm wide), layering (1- 3 mm), antennae (up to 1 mm), photographic images, etc.
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New methods of jewelry are being developed - plasma spraying of metals, glass powders, photochemical engraving, etc.
The production process ends with acceptance control and labeling of products.
Glass products in accordance with the purpose are divided into three classes: household, architectural and construction and technical.
The range of household products is classified according to many criteria.
1. By 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 from sodium - calcium - silicate, special household, crystal glass etc.
3. According to the molding method, blown, pressed, press-blown products, as well as those obtained by centrifugal casting, are distinguished.
4. According to the color of the product, there are colorless, colored and with a color.
5. By size, the products are divided into small, medium, large and extra large. The size of products is characterized by diameter, length or height, and the size of hollow products is characterized by capacity.
6. In terms of completeness, household glass products are piece and complete.
7. According to the method of applying jewelry (see earlier).
Modern trends in the decor of glassware - expanding the range of colored glasses, a combination of colored and slightly muted glass in the overlay, contrasting combinations of diamond-cut elements in the pattern, matte engraving, a chandelier, the widespread use of decal patterns and silk-screen printing of various subjects, pictorial cuts with paints and gold, often in combination with matting. Harvest 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 sticky (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 at the bottom of the product).
The leg of the products must be of different heights, shapes (straight or figured) and processing (faceted and even). The style, along with the aesthetic features of glass mass and cutting, largely determines the artistic expressiveness of products. It is subject to change in accordance with the requirements of the style.
Assortment of glassware.
The range of glassware, based on the method of production and purpose, is divided into the following groups: blown products, pressed products, press-blown products, crystal products, household utensils, kitchen utensils.
The range of blown dishes is very wide. These are glasses, glasses, glasses, glasses, wine glasses, jugs, decanters, sugar bowls, butter dishes, vases for table setting (for fruit, jam, cookies, cream, sweets, salad bowls), bowls, etc.
The range of pressed tableware is considerably narrower. These are saucers for jam, trays, vases, lemon squeezers, glasses, sugar bowls, glasses, salad bowls, sugar bowls, etc.
Press-blown tableware has a limited range. It's decanters different styles and containers, oilers, canteens, etc.
Household utensils include products used for storing and preserving food products (thermoses, jars, jars for pickles and jams, kegs, bottles for storing liquids).
Cookware made of heat-resistant glass is represented by pots of various capacities, baking dishes, braziers, frying pans. For the manufacture of dishes for cooking on an open fire or in microwave ovens, heat-resistant glass (borosilicate glass) is used. Get such dishes by pressing. Products made of borosilicate glass are subjected to a special tempering treatment to increase thermal resistance and are not decorated. Hardening consists in heating the products to 700 ° C and subsequent rapid and uniform cooling by air blowing. In this case, high, uniformly distributed residual stresses arise in the glass, which increase the impact strength by 5–8 times, and the heat resistance by 2–3 times.
Crystal products. They are obtained mainly by blowing and pressing-blow method. The range of blown crystal products is close to blown glassware. They produce crystal products both piece and complete.
Assortment of decorative products- These are glass sculpture, flower vases, toilet utensils, horn-shaped glasses, dishes, etc.
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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 glass products (using the example of a pluda) provide for the possibility of their performing two basic functions: "accept" and keep food and drinks in the same quantity and quality, and "give" them in whole or in part as they are extremely important. 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 store food and drinks is determined by the following group indicators: chemical resistance to food and drinks, resistance to weathering, resistance to thermal effects, resistance to mechanical stress. The ability to "give away" food and drinks: the functionality of a volume-spatial solution and versatility.
Ergonomic properties predetermine, first of all, the convenience (comfort) of use and hygiene of glass products. The comfort of household utensils is determined by the convenience of holding, transferring, performing storage, washing functions, as well as ease 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, the rationality of the 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 correspondence of the form of the product to the functional purpose and conditions environment, correspondence of tonal and color solution individual elements to the requirements of ergonomics, style solutions - to the interior, manufacturing technology - to the properties of the material. Informativeness of glassware is determined by the symbolism, originality and compliance with their style and fashion prevailing at the time.
The property of reliability of glass products is determined by their durability and storability. The most important 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 ʼʼVarious glassware. The nomenclature of indicators eyʼʼ 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, annealing quality indicators; - indicators of ergonomic properties - the content of harmful substances; - indicators of aesthetic properties - accuracy of reproduction of the author's sample, indicators of compositional integrity, informational expressiveness, perfection of industrial production of products, as well as refractive indices, average dispersion, light transmission ͵ faceting angle; - economic indicators - the mass of products (consumption of raw materials), cost.
Quality assessment and quality requirements for glass products.
The quality of glassware and decorative glass products must comply with the requirements of GOST 30407-96 ʼʼ Glassware and decorative glassware. OTU.ʼʼ. Quality assessment is carried out by organoleptic (appearance assessment) and physico-chemical methods (sizing, thermal stability, etc.). In terms of structural and dimensional features, household glassware must comply with approved samples. The product on a flat horizontal surface should not swing. Products that come into contact with hot food (tea glasses and saucers, hot food plates, etc.) must be thermally stable. Blown products should not be destroyed at temperature drops of 95-70-20C, pressed - at 95-60-20C.
Products are not allowed: chips; cut edges; stuck pieces of glass; cutting and crumbling glass particles when decorating products "in bulk"; through passages; foreign inclusions that have cracks and cracks around them. The end surface of the upper 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 product handles and decorative elements must be durable. Permissible migration of harmful substances emitted from glass products in contact with food products is established by the State Sanitary and Epidemiological Supervision authorities in the relevant regulatory documents approved in the prescribed manner. Defects in glass products are divided into defects in glass mass, production and processing.
To glass defects include:
1. Gas inclusions (ʼʼmoshkaʼʼ diameter more than 0.8 mm and ʼʼʼʼʼ diameter less than 0.8 mm) are formed as a result of insufficient clarification of the glass mass. Turbid and squeezing bubbles in the product are not allowed.
2. Strands and schlieren are transparent inclusions that differ from the bulk of the glass in composition or physical properties. Svili are thread-like inclusions, and schlieren are tubercles, nodules, glass clots.
3. Solid inclusions (stones, crystals). Occur as a result of crystallization of glass mass.
4. Insufficient discoloration - the result of the presence of metal oxides in the glass.
Production defects:
1. The difference in thickness in the glasses and the bottom of the product is the result of an uneven distribution of glass mass.
2. Chips and crevices;
3. Scree-small chips;
4. Forged-unevenness in the form of fine waviness of the surface;
5. Wrinkles - unevenness in the form of ripples on the surface;
6. Folds - uneven pocket shape.
Curvature, folds and wrinkles on products are not allowed.
Consumer properties and quality indicators of glass products - concept and types. Classification and features of the category "Consumer properties and quality indicators of glass products" 2017, 2018.
Functional (consumer) properties 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 sample, the properties of glass and the quality of workmanship. They are based on the natural properties of glass, due to its nature, composition and structure, methods of obtaining products, decoration. The following groups of consumer properties of glass household products are distinguished: purpose, ergonomic, aesthetic properties, reliability. In view of the greatest diversity of the assortment of glassware among all glass household goods, it is advisable to consider a detailed description of the consumer properties of glass products using the example of glassware. Functional properties are determined by the purpose of the dishes, their ability to accept, store and give away food and drinks (Table 3.5).
Purpose glass products provides for the possibility of their performing two main functions: to accept and preserve the functional properties of glass household goods (dishes)
Table 3.5
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Group |
single |
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1. The ability to accept and keep food and drink in the same quantity and quality |
Chemical resistance to food and drink |
alkali resistance |
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Acid resistance |
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Salt solution resistance |
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Water resistance |
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Weather resistance |
Lightfastness |
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Humid atmosphere resistance |
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Thermal resistance |
Heat resistance |
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Heat resistance |
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Thermal conductivity |
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Resistance to mechanical stress |
impact strength |
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Compressive strength |
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Hardness |
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Surface stability |
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2. The ability to give food and drink in whole or in part as needed |
Functionality of the volume-spatial solution |
Fit for purpose |
|
Fit for purpose |
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Versatility |
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Possibility of use for various kinds drinks and food |
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accept food and drink 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 variability of the shape and size of products.
Ergonomic properties predetermine the convenience (comfort) of use and hygiene of glass products. The comfort of household utensils is determined by the convenience of holding, transferring, performing the function of storage, washing, as well as the convenience of transportation and storage, and this is ensured by the general parameters of the product, the shape, size and location of individual parts, weight. Hygienic properties are primarily due to nature, properties, glass and style features. They are characterized by such group properties as harmlessness and contamination.
Glassware is chemically resistant and harmless, however, some paints and finishes may not fully meet these requirements due to their salt content. heavy metals. Bulky, inconvenient shape and design of products can also reduce their hygiene, making it difficult to clean in hard-to-reach places.
Aesthetic properties glass household goods are determined by the integrity of the composition, the rationality of the form and information content. Glassware, like other products, is designed to perform an important aesthetic function, thereby satisfying the spiritual needs of consumers, cultivating taste, a sense of beauty, and contributing to the creation of coziness in housing, a feeling of comfort at the table. Aesthetic properties are formed at the design stage of products, 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.
Reliability property glass products is determined by their durability and storability. Such indicators of durability as non-failure operation and maintainability are uncharacteristic for glass products. The most important is durability, which is characterized by physical and moral wear and tear. Optimal is the coincidence in time of performance of utilitarian and aesthetic functions, i.e. physical and obsolescence.
quality requirements glass household goods are diverse, they are set out in GOST 30407-96, GOST R 51969-2002. They can be grouped as follows: requirements for the quality of the reference sample, the technical design of the product, labeling, containers and packaging.
Household glass products must meet the following general requirements: have a convenient rational shape (style), the necessary mechanical strength, thermal stability, and also meet hygienic and aesthetic requirements: good transparency (especially for crystal products); the surface of the products must be clean, shiny and with a clear pattern. In addition, glass household goods must conform to the reference sample of the purchase in terms of shape, size, nature and type of finish.
Quality control of these products in trade is reduced to establishing their conformity in shape, dimensional characteristics, types of processing, selection and number of items in the set to drawings and standard samples approved in the prescribed manner. The higher the quality of the reference sample, the higher the level of its consumer properties, and hence the level of properties finished products in full compliance with the standard sample. Without agreement on the replacement of the assortment or in the case of delivery of products that do not correspond to the standard sample, the trade enterprise has the right to refuse to accept the goods.
In the case of full compliance of the goods with the reference sample, the next step is to check the quality of manufacture, i.e. compliance with regulatory documents and the grade indicated in the accompanying documentation and on the labeling of products. In accordance with the current regulatory documents, tableware and household utensils made of ordinary glass are not divided into grades. Crystal and household heat-resistant dishes are of the 1st and 2nd grade.
When accepting glass products, 100% of the batch is accepted for “visible” and “audible” breakage. When a fight is detected, the calculation of the fight rate is carried out. The battle within the established norms is debited to the “Distribution costs” account of the trade organization. Fighting standards are established for domestic and imported goods, for wholesale and retail trade enterprises, depending on the distance of transportation and mode of transport. With an increase in the distance of transportation and delivery by mixed modes of transport, the fighting rates increase.
In accordance with the Decree of the State Standard of the Russian Federation of December 1, 2009 No. 982 “On Approval of the Unified List of Products Subject to Mandatory Certification and the Unified List of Products, Conformity Confirmation of Which is Carried out in the Form of a Declaration of Conformity” are subject to:
- obligatory certification: glassware for children (OKP code 5970);
- declaration of conformity: glassware for adults (5970); household utensils made of colorless heat-resistant glass and household utensils made of glass-ceramics (5982); glass canning containers, including jars (5986); glass bottles (5987).
Glass defects. The quality of glass household products depends on the presence of defects that adversely affect the mechanical, thermal, optical, aesthetic and hygienic properties. Defects in glass products are divided into three groups: defects in glass, production and processing. Characteristics of glassware defects are given in Appendix 10.
A mandatory requirement for decoration is the clarity of lines in the drawings, uniform velvety and matte surface, light (to complete transparency) polishing of all elements of the drawing.
The effect of a particular defect on the quality of a product depends on its type, location, size, as well as the size of the product, etc. For example, defects in glass melt violate the uniformity of the structure and thereby sharply reduce the strength and optical properties of glass. According to these features, some defects are allowed with a limitation in quantity, size, others are not allowed at all.
Products that do not spoil the presentation are allowed: processed chips, rarely located streak and “scrotum”, overmelting of the edge; traces of surface disturbance in the form of scratches, folds, wrinkles, superficial cuts, etc. These indicators are often monitored visually using a magnifying loupe. Defects may be assessed using control samples agreed by the developer of the standard or the consumer.
On products are not allowed: chips, cut edges, stuck 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 dimensions of foreign inclusions and bubbles are checked using a measuring tool.
The standards provide a plan and procedure for conducting acceptance control. The value of the acceptance level of defectiveness is 4%.
Special requirements apply to the labeling and packaging of glass household goods. These are the factors on which the preservation of their quality largely depends. The marking is applied to a paper label and glued directly to the product, the use of silicate glue is not allowed. The label can also be stuck on consumer and transport containers or applied with a stamp. The marking is applied to each product, in a set - at least one product, in sets - on the largest product and at least two others. On small and medium-sized pressed products without refining, it is allowed to apply marking in the process of working out to the bottom of the products.
On boxes with glassware, handling signs should be applied - a glass, an umbrella, “CAUTION, FRAGILE”, “TOP, DO NOT TURN”.
In general, the requirements for packaging are that it should preserve the consumer properties of products during transportation and storage as much as possible. Retail packaging is subject to additional requirements in terms of its beauty and advertising expressiveness.
Products are transported by all types of transport in covered vehicles in accordance with the rules for the carriage of goods in force for this type of transport. Glass products are stored in bright, closed and dry rooms, protected from the influence of atmospheric precipitation. Optimal conditions for storage - temperature 20 ± 5 °C, relative humidity in the room 60 ± 5%.
When using dishes for long-term preservation of quality, you should follow some rules for caring for it. Manufacturers provide batches of products with accompanying documentation, which, in addition to marking data, contains instructions for caring for products, especially for dishes with specific properties such as glass-ceramic, tempered - “D yura leke” from borosilicate glass. Glassware is easy to clean detergents, but do not use metal ruffs, brushes to prevent scratches on the glass. The “plaques” formed during the operation of the dishes can be removed with a solution of two or more tablespoons of vinegar in a glass of water. The shine of the dishes will increase if, after washing, rinse them first with salted and then plain water. After washing, it is recommended to wipe crystal products with a woolen napkin with starch blued with blue. This will improve their shine. Products decorated with gold preparations, decals are not recommended to be washed with soapy water or soda solution. Dishes made of tempered, heat-resistant glass must not be washed with powders containing abrasive substances, must not be cleaned of burnt food residues with knives or other scratching objects. When cooking in heat-resistant cookware, it should be heated slowly.
After removing from heat, allow the dishes to cool and then wash them. Proper handling of your cookware will prolong its life and reduce the amount of time it takes to care for it.
When conducting an examination of glassware, they are guided by the instructions on the procedure for conducting an examination of goods by expert organizations and the requirements of regulatory and technical documentation. The procedure for conducting an examination depends largely on the purpose of the examination.
During the examination, the following are determined:
- 1) compliance of the quality of goods with applicable standards;
- 2) the correctness of the name of the product, its purpose and compliance with the labeling and accompanying documentation;
- 3) decrease in the quality of goods in the process of production and transportation;
- 4) causes of defects;
- 5) the validity of the write-off of damaged goods from the accountability of financially responsible persons, etc.
A batch of goods that is heterogeneous in composition must be sorted by assortment (name, article numbers, sizes, etc.) before the examination. Then each group of goods is checked for compliance with standard samples in terms of style, size, capacity, weight, glass composition, molding method, decoration method. If the customer submits several consignments of goods at the same time, each consignment is checked separately, taking into account the shipping documents.
To check the compliance of the overall dimensions of the container product with the data of the documents, a millimeter ruler, caliper, probe, measuring cup or cylinder are used.
Overall dimensions (height and diameter) of the product are determined by rulers, right-angled triangles. Oval products are measured in height and in large and small diameters. The point of intersection (vertically and horizontally) of the two rulers is the height of the product.
When checking the container, water (temperature 20 ° C) is poured into vials, bottles, decanters - to the point of transition to the throat; in jugs, jars - to the bottom edge of the lid; in other products - to the brim.
To determine the thickness of the walls, neck, bottom of the product, use a caliper.
A wedge-shaped steel plate or a vernier caliper is used to determine the bevel of the edge and the deformation of the body of the product. The gap between the edge of the product and the plane, the difference between the maximum and minimum height is determined.
The quality of glassware and decorative glass products must comply with the requirements of GOST 30407-96. According to GOST, in the general technical requirements, products that do not spoil the presentation are allowed:
Processed chips;
Rarely located striation;
Rarely located "midge";
A bubble in the form of a sickle at the junction of individual parts of the product and decorative elements;
Edge remelting;
Traces of violation of the surface;
Traces from molds and scissors;
Traces of distillation and polishing;
Not finishing and lengthening the lines of the drawing;
Defects in decoration with preparations of precious and other metals, luster and silicate paints;
Torsion in products of mechanized production;
Thickening with one protrusion on the upper edge of the glasses made of sodium-potassium-silicate glass;
Waviness of the surface of the faces;
Deviation in the drawing from the reference sample, caused by the need to eliminate defects;
Asymmetry of the junction of the vessel and the bottom, an annular thickening or waviness in the places of the junction of the vessel and the stem, legs and bottom.
5.1.4 The number and size of foreign inclusions that do not have cracks and cuts around them should not exceed the values \u200b\u200bgiven in Table 2.
table 2
On the parts of the products decorated with colored chips, foreign inclusions not exceeding 1 mm in size that do not spoil the presentation are allowed. in the amount of not more than 3 pcs. for small and medium products, no more than 5 pcs. - for large and extra large products.
Depending on the size of the product, they are divided into groups in accordance with table 3.
Table 3
The group of products is determined by the largest parameter.
M a r k i r o v k a
Products are marked on a paper label, which is glued directly to the product (the use of silicate glue is not allowed) or during the production process. The marking of consumer (group and (or) individual) containers, group packaging made of paper 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 labeling of products on a paper label indicates the following data:
§ vendor code;
§ mass fraction of lead oxide (only for lead crystal);
The label is placed on each product. In sets, the label will be placed on at least one product, in sets - on the largest and smoldering on no less than two others.
It is allowed not to indicate the article in the labeling of products packed in individual containers.
Marking in the process of development must contain a trademark or the name of the manufacturer.
The composition of the kit or service is indicated on the consumer packaging or on the largest product.
It is allowed, in agreement with the consumer, not to apply marking on products or to apply to part of the products in a batch.
Products intended for export are marked in accordance with the terms of the agreement or contract.
The labeling of consumer (group and (or) individual) containers and group paper packaging indicates the following data:
§ trademark and (or) name of the manufacturer;
§ name of products;
§ vendor code;
§ number of products in a packaging unit (for group containers);
§ number of controller and packer;
§ designation of this standard.
For certified products, the sign of conformity or the number of the certificate of conformity is affixed to the product marking on a paper label and (or) in the marking of containers and packaging, as well as in the shipping documentation.
Transport marking - in accordance with GOST 14192 with the application of the handling sign "Fragile - Caution".
It is allowed to apply the image of a manipulation mark on a label intended for marking containers.
Package
Products are packed in consumer and transport containers.
Specific types of containers and packaging that ensure the safety of products during transportation, gross weight are indicated in contracts for the supply of products between the manufacturer and the consumer.
Safety requirements
Permissible migration of harmful substances emitted from glass products in contact with food products 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 Appendix A.
The water resistance of products must be at least hydrolytic class IV (4/98).
Glasses and saucers for tea, plates for hot food must be thermally stable. Blown products ms should be destroyed at temperature differences of 95-70-20C, pressed - at 95-60-20C.
Products are not allowed: chips;
cut edges; stuck pieces of glass;
cutting and crumbling glass particles when decorating products in bulk; through sections; foreign inclusions with cracks and cuts around them.