All about car tuning

Requirements for the quality of glass household goods. Assessing the quality of glass goods. Types of cutting glassware

Products made of glass and crystal, which are subjected to sudden heating and cooling and 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 catering industry 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.

The ergonomic properties of products are primarily ease of use (comfort) and hygiene of glass products.

The comfort of household utensils is determined by the ease of performing their functions, keeping them clean, and storing them. At the same time, the shape and capacity of the product, the presence and location of handles, and the correspondence of their shape to the fingers are taken into account. When assessing the ease of care of 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 the ease of transportation, packaging, and storage of products.

The hygienic properties of tableware are determined primarily by the nature and properties of glass. Products must have high chemical resistance and be harmless to the human body. When assessing hygiene, the simplicity and ease of removing various types of contamination from the surface of products and keeping them clean are taken into account.

The aesthetic properties of glass products are characterized by the integrity of the composition, rationality of form and information content.

Undefined contours of both the entire product and its elements, poor color and design, hiding the natural properties of the material, worsen the aesthetic perception of the product’s shape.

The ratio of the sizes of parts, sides, and patterns characterizes the proportionality of the product.

The reliability of glass products is determined by their durability. Products with attached parts, high legs, and complex configurations are less reliable.

Products must have a shiny, smooth surface, polished to complete transparency.

The edge and end surface of the top edge of the products must be melted or polished. A bevel is applied to the edge of the upper edge of the products or other types of processing are used. Lids and plugs must be selected for the products.

Lids must cover or fit into the products freely. The difference between the diameter of the lid and the edge of the body (or neck) should not exceed 2 mm.

Plugs with unworn stems should fit freely into the neck of the product. The ground stem of the cork should fit snugly to the neck of the product. In toiletries, the stem of the cork must be ground in.


The spout of the product should be located opposite the handle.

Attaching adhesive parts and decorative elements should be simple.

The bottom of the products must be smooth, clearly polished, and 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.

The products in the set must be selected so that the difference in height between them does not exceed the permissible deviation from parallelism of the edge of the bottom plane.

The difference in the edge thickness of the walls should not be more than 0.5 mm for products with a wall thickness up to 3 mm inclusive and 1 mm for products with a wall thickness over 3 mm.

The quality of household glassware depends on the presence of defects that negatively affect its mechanical, thermal, optical, aesthetic and sanitary properties.

The impact of a particular defect on the quality of a product depends on its type, location, size, and also on the size of the product.

Based on these criteria, some defects are allowed with restrictions on quantity, size and location, while others are not allowed at all.

Defects that do not affect the consumer properties of products.

Defects are allowed in glass products that do not spoil the appearance and are permitted by the requirements of the agreement/contract:

Weakly expressed bluish tints in products made of lead crystal;

Differences in the intensity of coloring of the same product made of colored and applied glass, caused by uneven wall thickness;

A barely noticeable difference in the density of the color shade of parts of sets or sets between large and small items of the set for products made of colored glass;

Barely noticeable rocking of the plug in the neck;

A ring-shaped protrusion no larger than 1.5 mm in size on the inner surfaces of the bottoms of products on a leg, manufactured in a multi-stage method;

Small deviations in the height and width of the teeth located along the edges of the products;

Small deviations in coloring, engraving from the drawing or sample, which do not violate the artistic design of the product;

A small addition of a pattern or polish that would not interfere with the presentation of the product;

Guten products have transparent bubbles, single foreign inclusions;

Foreign inclusions up to 0.5 mm in size inclusive, in an amount of no more than 2 pieces. on medium, large and especially large products;

The bubbles are transparent, closed, without cracks or cuts around them, ranging in size from 0.8 to 2 mm in the following quantities:

For small items - 1 piece;

For medium ones - 2 pcs.;

For large ones - 3 pieces;

For especially large ones - 6 pieces;

The style is single, barely noticeable;

- “midge” is single, rarely located on all products except small ones;

The difference in thickness between the edges of the walls and the nominal thickness is no more than 15%;

Non-parallelism of the edge of the bottom plane (bottom slant):

For small ones, no more than 0.5 mm;

The average ones have 1 mm;

For large ones 1.5 mm;

For especially large ones, 2.0 mm.

Defects affecting consumer properties.

Defects that are not allowed on glass products regardless of size at locations:

Foreign inclusions with cracks and settlements around them;

Foreign inclusions that do not have cracks or nicks around them, in tea glasses, cups, teapots;

Glass cutting stick;

Notches, cracks;

The cutting mark of the scissors is cutting;

Blown glass;

A sharp, cutting edge or edge of a product;

Underpressing, scratching burrs;

Undermining of attached parts;

Impact marks from a tool with cracks around;

Burnt paint, decals with peeling and abrasion;

A bubble pressing on the inner surface of products for eating and drinking;

De-vitrification along the edges of products for eating and drinking;

Unmelted scree along the edges of the products;

Chips and chips, unfixed or partially melted or painted over and scratching along the edges of products for eating and drinking;

Cutting slipper.

If you find any defect on the product, you must make sure that it does not spoil the appearance.

Defects that spoil the appearance of products reduce the quality of products depending on the location, size of the defect, as well as the product itself.

Glassware- depending on the purpose, it is divided into dining (varietal) and household.

Tableware(varietal) has a wide variety of assortment; grouped according to the following characteristics: production method, types, styles, sizes and nature of glass. According to the production method, tableware is divided into blown, pressed and press-blow.

Types of tableware are very diverse: glasses, saucers, decanters, shot glasses, goblets, goblets, jugs, milk jugs, sugar bowls, oil dishes, vases, salad bowls, crackers, teapots, cheese caps, ashtrays, toiletries, jugs, water utensils, liqueur and etc. All types of tableware (glasses, wine glasses, goblets, jugs, milk jugs, teapots, liqueur, crock, water and some other products) are produced using the blowing method, the shape of which excludes the possibility of using pressing. By pressing methods - products whose upper diameter is larger than the lower and middle (ashtrays, herring containers, beer mugs, stands for knives and forks, saucers, glasses, glasses, plates, etc.).

The styles of tableware are very diverse; they are determined by the design of the product and the shape of the body; By design they can be with or without a handle, without a leg or on a leg, etc., and by the shape of the body - spherical, oval, conical, etc.

The dimensions of the dishes are determined by the capacity of the products (glasses, decanters, jugs, etc.), diameter (plates, dishes and other flat products), height (flower vases), top diameter and height (vases for fruit, cookies, cream and jam). According to the nature of the glass, dishes are made from ordinary colorless glass, colored glass, colored glass, and crystal glass (colorless, colored, and colored).

Types of cutting glassware

Household dishesIts product range includes jars and barrels for pickles, jars for jam and milk, jars, jars, bottles, thermoses and flasks for home-canned foods, siphons, etc. This group also includes heat-resistant kitchen utensils manufactured made of special glass, usually transparent or having a slightly greenish-yellowish tint. Thanks to special hardening, this cookware has high thermal stability. It can be placed directly on electric stoves or in the microwave, subject to certain precautions (gradual inclusion of gas) - on gas stoves. It includes: cast-rules, frying pans, braziers, so-called ducklings, baking dishes, teapots, coffee pots, milk jugs, mugs, glasses, cups with saucers, plates, dishes, sauces, etc.

For the production of glassware, potassium-sodium-lime glass (the so-called ordinary glass) and potassium-lead (crystal) glass are usually used - Glass.

Tableware is made in two main ways: blowing and pressing.

Cutting glassware with diamond cut

Blowing utensils mainly (with the exception of tea glasses) produced manually using a blowing tube (a metal tube with a rubber reservoir - balloon); Glass melt is collected at the end of the tube, which, under the pressure of injected air, turns into a thick-walled bubble called a “jar.” Using various techniques, the “jar” is transformed into a so-called “bullet”, with such a distribution of glass as is necessary for blowing the finished product. The “bullet” is placed in a special mold and inflated under the pressure of blown air, the glass mass is pressed against the walls of the mold, taking on its outline, and in this form it freezes. If products have handles and legs (shot glasses, jugs, etc.), then the latter are made separately and then, in a softened state, attached to the body of the product. Machine blowing carried out on various types of machines. Thus, in the USSR, glasses were produced on VS-24 machines, decanters - on LVM machines, glass jars - on LAM machines.

Machines in which the “bullet” is produced by pressing and the product by blowing are called press-blow machines. Such machines include, in particular, the LVM machine.

Pressing carried out on manual, semi-automatic and automatic presses; it is much more productive than blowing. During pressing, the glass melt is fed into special molds. Under the influence of the core descending into the mold ( punch) glass melt fills the space between the walls of the mold and the punch and takes the shape of the product. All products are annealed in special furnaces: kept for several minutes at a temperature of about 500° and then slowly cooled. Annealing reduces residual stresses to an acceptable value. Unannealed or poorly annealed glass products will crack with minor temperature changes and slight shocks.

Glassware processing consists of separating the cap, processing the edge, and sometimes the bottom. To separate the cap on the body of the product, a line is made with a diamond and then a sharp flame of a gas burner is directed at this line. The cap then bounces off. The resulting uneven edge of the product is ground and then polished or melted with the flame of gas burners. The bottom of the products is first ground and then polished.

Glassware decoration produced in various ways. The main ways to decorate blown glassware during the blowing process are: inflated, marbled, with colored threads, with a wavy surface (roller), iridescence, etc. Dishes with inflorescence have two or more layers of glass, of which one is usually colorless. In dishes decorated with marble, between two layers of glass, one of which is milky and the other colorless, there are pieces of colored glass interspersed. For dishes with colored threads, the latter are either in the thickness of the glass or on the surface. Dishes decorated with a roller have vague longitudinal edges of varying widths on the body, while those decorated with iridescence have rainbow tints. Recently, the glass industry has been using a new method of decorating tableware, called “sulfide” glass. It consists in introducing zinc sulfide into the glass mass, which partially decomposes during the manufacture of tableware to form iron sulfides, which color the glass in a variety of colors.

Decoration of finished dishes (after processing) is done in various ways: matte tape, decorative grinding, engraving, etching, painting, gilding, decalcomania, photography, etc.

Matte tape- the simplest pattern resulting from processing a rotating product using a metal plate with sand and water. Decorative grinding is achieved using rotating carbon-rundium wheels that remove, or rather cut through, the top layer of glass and form edges of various shapes and depths.

Depending on the nature and complexity of these edges, grinding is divided into: simple or gross (in the form of round or oval pits); number plate with more complex designs; lettered or washer (wide edges); a diamond cut in the form of various deep slits (most often triangular in shape), forming patterns consisting of beams of rays, meshes, rhombuses, polyhedra, stars, etc. The diamond cut is distinguished by a variety of patterns and is divided into 10 groups according to complexity. The diamond cut is especially widely used for decorating crystal products, which are usually made with thick walls. The diamond edge clearly reveals the nature of the glass material and gives the products a greater play of light (color refraction).

Decorating glassware with a diamond cut (first difficulty group)

Engraving It is produced using rotating small copper discs and a special grinding paste. It can be matte or shiny - polished. Engraving produces designs mainly of a plant nature (flowers, leaves, berries, etc.).

Etching based on the property of hydrofluoric acid to dissolve glass. Depending on the complexity and depth of the drawing, the following are distinguished: types of etching: simple, or guilloche, pantographic- with a more complex pattern (both names come from the name of the machines with which patterns are drawn on products coated with waxy mastic) and deep artistic, performed mainly on products with color.

Painting on dishes is done with a brush using special silicate paints, fixed to the products by additional firing. Picturesque designs are most often applied to products made of colored glass or glass with color, predominantly milky white.

Painting products with gold, decorating them with decalcomania and the photographic method, which was previously used only in ceramic production, is widespread ().

Depending on the nature and complexity of the decoration, blown glassware is divided into complexity groups from No. 1 to No. 7, and thick-walled crystal - from No. 5 to No. 10.

Pressed dishes, as a rule, are not subject to additional decoration, since the design on them is obtained during the manufacturing process. A small part of pressed products is decorated by matting individual parts of the design (matting can be chemical or sandblasting), as well as grinding, polishing and gilding.

Decorating glassware with a diamond cut (second difficulty group)

Quality requirements and sorting. The quality of glassware depends on the rationality of the design of the product, which determines the ease of use; on the shape of the product, which affects its artistic value; on the quality of raw materials; the manufacturing and finishing process, which influences the appearance of the product and its operational properties - thermal, mechanical resistance, etc.

The use of low quality glass and violations of production technology cause the formation of a number of defects on products.

Glassware defects

Glass melt defects

1. Violation of colorlessness, resulting in different shades in the glass. Blurred shades (pinkish, bluish) are allowed.

2. Stone - foreign inclusions in the glass (particles of refractories or charge) sharply reduce the heat resistance of the glass. Not allowed.

3. Schlier - clumps of glass in the form of tubercles, usually having wavy branches.

4. Svil, which is wavy stripes in glass.

5. A bubble, which is gaseous inclusions in glass, transparent and cloudy (alkaline bubble), over 0.8 mm in size.

6. Midge - small bubbles, up to 0.8 mm in diameter.

7. Rukh, which is crystallized opaque glass particles.

Production defects

1. Uneven distribution of glass melt, resulting in a noticeable difference in the thickness of the walls and bottom of the products.

2. Blowout of the walls of the product - a sharp decrease in wall thickness in certain places.

3. Ovality of the body, bottom and tray, which violates the correct shape of the product.

4. Scale, which is the result of inclusion of iron particles from the blowing tubes.

5. Asymmetrical fastening of parts - violation of the symmetry of handles, legs, etc.

6. Curvature of the product - violation of the correct shape of the product.

7. Shcherbiny - depressions along the edge of the product.

8. Edge fraying is a small pitting of the edge of the product.

9. Chips - damage to the integrity of the side walls of products at the edge.

10. Cuts - small hairline cracks on products.

11. Scratching and scratches - stripes from scratching the walls of products with hard objects.

12. Gaps between the body and the cover.

13. Excess - burrs from the seams of the mold.

14. Underpressing - violation of the shape of pressed products; is the result of a lack of glass melt.

Processing defects

1. Traces of distillation (fine grinding).

2. Re-melting of the edge - curved inward and heavily melted edges of thin-walled products.

3. Skewed edges - violations of the correctness of the design, in which gaps and breaks in the matte tape and etched designs are noticeable, asymmetrical patterns, collapse of edges, blots, bulges, moles and burnouts in the picturesque cuts.

Decorating glassware with a diamond cut (third group of difficulty)

Based on the presence of these defects, blown and pressed crystal glassware in the USSR was divided into 1st, 2nd and 3rd grades; blown tableware and heat-resistant glassware - 1st and 2nd grade. Pressed tableware and household tableware made of ordinary glass were not divided into types. When establishing the grade, the type of defect, its size, location (on the body or at the bottom of the product), the method of making the dishes, the size and, in some cases, the nature of the decoration of the product, were taken into account.

There are a number of general requirements for glass tableware. The main ones are: correct shape and stability of products. The lid of sugar bowls, oil dishes, vases, jugs and other products must be selected according to style and color and fit tightly (without gaps) to the body. Stoppers for decanters should be selected according to style and color and tightly ground to the neck, and for decanters with more valuable cuts (diamond cut, etc.) the stoppers should be polished until completely transparent. The edge of blown and pressed products must be well melted or ground and polished. The inner surface of the bottom of saucers, trays and plates must be flat, ensuring the stability of the glasses placed on them. The edges of the bottom should not be sharp. Stones, scale, crumbling edges, nicks, blown walls, alkaline and surface bubbles, pressing through unfilled (with sharp edges) chips, and under-pressing are not allowed in the vessel.

Household utensils must have the correct shape and specified dimensions. Cracks, stones, large streaks, cloudy bubbles, air leaks and significant thickening are not allowed in this container.

A very important indicator of the quality of glassware is its thermal resistance, i.e. resistance to sudden temperature fluctuations. To check the thermal resistance of the dishes, samples in the amount of 100 pieces were taken from the batch. Thermal resistance was tested by first exposing the dishes to high temperatures (boiling water is poured, immersed in heated water, and other methods), and then low (usually immersed in water with a temperature of 15 or 20°).

Marking. Blown and pressed dishes were marked with a stick-on label, which indicated the brand or name of the plant, product grade, standard number and decoration group. The color of the labels for different types of dishes was different. On packs of glass tableware, the article number of the packaged glassware and the pattern number were additionally indicated.

Packaging and transportation. Crystal products, as well as products made from ordinary glass, but with valuable cuts, were wrapped in paper, and then in shavings and packed into bundles. Pressed tableware and household utensils were packed in straw or shavings. Glassware was transported in covered wagons or containers. Rows of bags or packs were lined with straw. Packs with heavier products were placed at the bottom, and with lighter ones at the top.

Storage. Glass is an easily breakable product; therefore, the warehouse for its storage had to be spacious, dry and convenient for receiving, placing and issuing goods. Glassware was stored on shelves and racks; it was laid on them not flat, but with its end, on the upper shelves it was lighter and slow-moving, on the lower shelves it was heavier, in particular pressed.

Decorating glassware with a diamond cut (fourth difficulty group)

Decorating glassware with a diamond cut (fifth difficulty group)

Decorating glassware with a diamond cut (sixth difficulty group)

Decorating glassware with a diamond cut (seventh difficulty group)

General information about glass household products

Glass as a material has a long history. Russian scientists - M.V. Lomonsov, K.G. Laksman, D.I. Mendeleev, N.I. Kitaigorodsky and others - made a significant contribution to the development of the science and practice of glassmaking. The main representative of this type of product is glass utensils that are used both for setting the table and for preparing and storing food. Its widespread use is due to its high demonstrated aesthetic properties, harmlessness, environmental friendliness, hygiene, etc.
Glass is a material with an amorphous-crystalline structure, obtained by supercooling a melt consisting of oxides of various metals.
Any glass contains at least five oxides. Taking into account the dependence on the composition (its main component), silicate (SiO2), borate (B2O3), phosphate (P2O5) and combined (borosilicate, etc.) are distinguished. The oxides that form the structure and properties of glasses are called glass-forming substances. In the production of household goods, silicate glasses and glasses based on their combinations are most widely used.
SiO2 is used as glass-forming oxides in silicate glasses, which is introduced in the form of quartz sand, Na2CO3 - in the form of soda, K2CO3 - in the form of potash, CaCO3 - in the form of limestone or chalk, broken glass and other components are also introduced. The quality of quartz sand and the absence of harmful impurities in it (iron oxides and ferrous oxides, etc.) have a significant impact on the colorlessness and transparency of glass (an example is “Bohemian” glass).
In addition to glass-forming substances, glass may contain the following components: bleaches, brighteners, dyes, opacifiers, oxidizing and reducing agents, glass melting accelerators. These components of the composition influence the aesthetic properties, functional purpose and technological performance of glass products.

Classification and assortment of glass household goods
The assortment of glass household goods (GHS) is quite wide; many characteristics are used to classify it, some of which facilitate the study of the assortment and its formation in trade enterprises (type of glass, forming method, type of decoration, purpose, completeness), others allow for quality control ( product shape and size).
Taking into account the dependence on the type of glass, household products are divided into products made from ordinary glass, crystal and special glass.
Common glasses include sodium-calcium-silicate (sodium-lime) and potassium-calcium-silicate (lime-potassium) glass. Glasses of this group are characterized by good transparency, strength, and low cost.
The cheapest representative of this group of glasses is sodium-calcium-silicate, which has color shades of varying degrees of severity (greenish, yellowish, grayish, etc.). This glass is used to produce household utensils (jars, bottles) and cheap, usually colorless, everyday tableware.
Potassium-calcium-silicate glass, due to the introduced potassium oxide, is more colorless, which makes it possible to obtain better products, in terms of aesthetic properties, colorless and colored (greater color purity is achieved). This glass is somewhat more expensive and is used mainly for the production of tableware.
The group of crystals combines glass containing lead oxides (PbO2). Lead oxide helps increase the density of glass, improves optical properties: transparency, “whiteness” (colorlessness), and increases the refractive index (brilliance, play of light). At the same time, these types of glass have a higher cost, lower hardness, chemical resistance and harmlessness. This group combines three types of glass: crystal glass (low-lead crystal); lead crystal and high lead crystal.
Crystal glass contains a minimum amount of lead oxide (according to GOST, the total amount of lead and potassium oxides should not be less than 10%), and therefore it occupies an intermediate position between ordinary glass and lead crystal in terms of optical properties and cost. Products made from crystal glass are usually produced by pressing, with a pattern applied from the mold; they are not subjected to manual decorative processing. The range of products is represented by tableware (mugs, salad bowls, herring bowls, vases for table setting, ashtrays, etc.).
Lead crystal contains at least 24% lead oxide. This type of crystal is superior to that previously discussed in terms of optical properties and density; when struck, products made from it produce a high, long-lasting sound (“crimson ringing”). Lead crystal is used in the production of tableware, festive assortment (shot glasses, glasses, wine glasses, cups, vases for table setting), decorative and utilitarian products (flower vases, souvenir mugs, ashtrays), and decorative items. Products are produced by blowing, pressing, multi-stage production, and in almost all stages they are subjected to manual finishing (decorated with a “diamond edge”, etc.), which increases the level of aesthetic expressiveness.
High-lead crystal (lead oxide content of at least 32%) is characterized by maximum cost and high potential for shaping the aesthetic properties of products. It is used to make expensive dishes, cups, decorative prize items, small sculptures, etc.
Previously, the domestic industry produced crystal products based on barium oxides and zinc oxides, and currently their production is limited.
The third group of glasses - special glasses - is represented by borosilicate (heat-resistant) glass and glass-like materials - glass ceramics. These types of glass are characterized by specific properties: increased heat resistance and mechanical strength (which is primarily inherent in glass ceramics).
Borosilicate glasses can withstand heating up to 500 °C and are resistant to thermal shock, which determines their possible use in the production of kitchen utensils: pots, braziers, frying pans, baking dishes, etc. Externally, this type of glass is easily recognizable by its reduced transparency, greenish-yellow color (imported products can also be painted in warm colors: orange-pink, rose-red, etc.) and massiveness of the products (large wall thickness is determined by the production method - pressing) .
Sitalls are glass-like materials with a crystalline structure (lithium, titanium and magnesium introduced into the composition of aluminosilicate glasses activate the process of crystal formation), maximum mechanical strength (tens of times superior to ordinary glass); high temperature resistance. These materials are also characterized by low transparency, most often have a white color, and dishes made from them have signs of pressed products.
Taking into account the dependence on the molding method, glass products are divided into five groups: pressed, blown, press-blow, multi-stage production, cast.
Pressing is the most technologically advanced method of producing glass products for this purpose. The process boils down to the formation of a product from molten glass mass placed at the bottom of the matrix, in the gap between the matrix (the stationary part of the mold) and the punch (the moving part of the mold). During the molding process, relief patterns and marking attributes can be applied to the surface of the matrix, which are transferred to the product during pressing.
At the same time, this method does not always emphasize all the advantages of glass: “airiness,” shine, and a high degree of transparency. Products obtained by this molding method are characterized by massiveness, large wall thickness, lower heat resistance (for products made from ordinary glass), simplicity of shape, their upper internal diameter is always larger than the lower one, due to the wear process of the molds, smoothness is lost and gloss decreases.
Blowing is a forming method that makes it possible to use the potential capabilities of glass to a greater extent; the blowing process can be carried out by mechanized and manual methods. The products of this production method are distinguished by the following features: a variety of shapes; high surface smoothness; a significant range of wall thickness (from very small - up to 1 mm, to very large - 10 mm or more); various types of jewelry (both simple and complex).
Products obtained by mechanized blowing are characterized by a simple shape with a central axis of symmetry and may have a thickened bottom. Examples of such products are thin-walled tea glasses, products with a stem (shot glasses, glasses, wine glasses).
The hand blowing method is more labor intensive and can be done freely and using molds. A variation of manual free blowing is guten work (gutny technique). Products of this production method are characterized by complex types of decoration and form an assortment of artistic and decorative products.
Press blowing is carried out in two stages: first, the product blank is pressed, and then the blank is finally blown into the mold in a hot state. Products of this production method have the characteristics of both pressed and blown products, but their distinguishing feature is the presence of a neck; traces (“seams”) from the connector of composite molds are often visible.
Multi-stage production (jointing) is used in the production of hollow products with a stem, in which the hollow part is blown, the stem is pressed, then both parts are articulated.
Decorative items (sculptures) and optical glasses are made by casting into molds (molten glass is poured into a prepared mold).
Taking into account the dependence on the type of decoration, a distinction is made between products with decorations applied during the molding process, as well as on finished products.
Decorations applied during the molding process include:
– coloring in the mass – a dye is introduced into the glass mass in order to impart a certain color (by their nature, dyes are molecular and colloidal);
– color – used for surface coloring of blown products, additionally emphasizing (by grinding, diamond cutting, etc.) the colorlessness of the base glass;
– optical pattern – the product is produced in two stages: at the first stage it is molded in a relief form, and at the second - in a smooth form;
– decoration with a “roller” resembles an optical pattern, but the front surface remains in relief;
– air bubbles – gas-forming inclusions are introduced into the glass melt (or individual elements of the product);
– colored spots, marble decorations, malachite, etc. – glass melts of different colors are mixed unevenly;
– crackle – the product after molding is sharply cooled, the resulting surface cracks are subsequently melted;
- decoration in bulk (crumbs) - the product is rolled hot over glass chips;
– decorations with glass threads, ribbons, glass cords;
– clings, decorative folds of edges, curly edges are obtained using a special tool in the process of free blowing of products.
Decorations applied to finished products are usually classified into three subgroups:
– mechanical methods of decoration;
– chemical decorations;
– overhead (surface) film decorations.
Mechanical methods of decoration include the following:
– grinding – removing the glass surface using an abrasive to form a certain pattern; a distinction is made between grinding with and without polishing;
– engraving – processing the glass surface with narrow engraved abrasive wheels (laser, ultrasound) to form a pattern; unlike grinding, the pattern is thinner, more textured, matte (not polished);
– diamond edge – the pattern is formed by dihedral grooves obtained on the glass using an abrasive, which can be additionally polished or not;
– sandblasting, waterjet processing – the formation of a pattern by chipping the glass surface with abrasives supplied by air or water flow, usually through a stencil.
Chemical decorations are currently used to a limited extent by the domestic industry due to their significant cost. These decoration methods are based on the destruction of the surface layer of glass with hydrofluoric acid. These types of decorations include guilloche, pantograph and deep artistic etching (the latter is usually characteristic of products with color).
Overlay (surface) film decorations are widely used for decorating products made of ordinary glass and glass ceramics; they are represented by the following types:
– painting – decorations with paints or gold preparations applied with a brush; designs can be both thematic and in the form of stripes (up to 1 mm - tendril, from 1 to 3 mm - layering, from 4 mm to 10 mm - tape);
– decal (decalcomania) – decorations applied using decals;
– silk-screen printing (silk-screen printing) – often a one-color design, reminiscent of a “thin” screen print;
– stencil – a single-color or multi-color simple drawing with paints, applied using one or several stencils, respectively (possible overlay of paints, lack of clarity of the outline);
– metallization, irrigation, plasma spraying – application of metal oxide, metal and other films to the glass surface to form a certain pattern;
– decoration with luster paints – when applying and subsequent firing of paints, a thin film with a specific effect is formed on the surface (golden luster, iridescent luster, etc.).
Glass household goods are divided into two main groups according to their intended purpose: tableware and artistic and decorative items.
In turn, each of these groups includes a number of subgroups: tableware should be distinguished - dining room, kitchen, household and universal; in artistic and decorative products - decorative-utilitarian and decorative.
The dining room includes utensils for serving food and drinks on the table and for eating food and drinks. Household utensils are products used for storing and preserving food products. Kitchenware includes products used for cooking on gas and electric stoves, mainly products made of heat-resistant borosilicate glass. Universal cookware is represented by glassware, it can be used both for cooking in microwave ovens and as a tableware (for serving and eating heated or cooked food).
According to the completeness, glassware can be piece or complete. Sets include sets (consisting of products of the same type); devices (sets consisting of products of different types, united by a common function); sets (sets consisting of products of different types, united by a common function and intended for 6 or 12 people); sets (combine several sets, for example a tea, coffee and dining room set).
Based on their shape, glass household products are divided into hollow and flat. Each of these groups is divided by size into small, medium, large and extra large. The size of flat products is determined by the largest diameter (mm), hollow - by volume (cm3), tall (vases) - by height and diameter (mm). Small products include products with a diameter of 100 mm, a volume of up to 100 cm3, and a height of up to 100 mm. Large ones – with a diameter of more than 150 mm, a volume of more than 500 cm3, and a height of up to 250 mm. Medium products include products with intermediate sizes. The size of especially large products is characterized by the following parameters: diameter more than 250 mm, volume more than 1000 cm3, height more than 250 mm.
It is advisable to consider the assortment of glass household goods using their classification by purpose.
The range of tableware includes items for making food and drinks: vases for table setting (for cookies, jam, fruit, etc.), salad bowls, butter dishes, decanters, jugs (usually with a handle, with a wide neck), damasks; for eating and drinking: jam sockets, plates, portioned salad bowls, glasses (for tea, water, cocktails, wine, etc.), products on a stem (shot glasses - volume up to 100 ml, glasses - volume from 100 to 200 ml, wine glasses - volume more than 200 ml), cups and saucers, mugs; complete and other products for table setting (napkin holders, trays, ashtrays).
Household utensils include jars, bottles, containers for bulk products and spices, cheese caps, teapots, thermoses.
Kitchenware (borosilicate) is represented by the following products: pots, braziers, frying pans, baking dishes.
Universal cookware (ceramic glass) for preparing, serving and eating food includes the following types of products: plates, pots, bowls, salad bowls, cups, etc.
Artistic and decorative products are presented in an assortment of decorative products: small sculptures, decorative vases, and decorative and utilitarian products: vases for flowers and table settings, ashtrays, etc.

Consumer properties of glass household goods
Due to the fact that the range of glass household goods is mainly represented by dishes, the range of their consumer properties is similar to that which was discussed in the section “Consumer properties of plastic products”.
When characterizing the consumer properties of glassware, their specificity should also be taken into account.
Functional properties. Glass is a material that is widely used for contact with food; its heat resistance is significantly increased due to tempering. The chemical resistance of crystal is lower than other types of glass; therefore, it is not recommended to store food products in this container for a long time. The ability to receive and give food, as well as the versatility of the utensils, depend on its type and design features.
Ergonomic properties. The convenience of performing basic and additional functions of glass products depends on the design features of the products, their shape and size. Glass has a smooth surface, which increases ease of care, however, relief and surface decorations applied to the products can reduce this indicator.
The safety properties of glass products are determined by chemical and mechanical safety. Chemical safety is determined by the type of glass, type and location of the decor. When characterizing mechanical safety, it should be taken into account that when glass breaks, fragments with cutting edges can be formed.
The reliability of glass products is determined by mechanical, thermal and chemical resistance. These indicators are significantly influenced by the type of glass, the thickness of the walls of the product, the type of decoration, and design features.
Potentially, glass products have high aesthetic properties, which proves the aesthetics of the material itself and the wide variety of decorations used.

Quality requirements for glass household goods

The quality of basic groups of glass household goods is standardized by GOST 30407-96 Tableware and decorative glassware, which applies to products made of ordinary glass and crystal and imposes requirements for appearance, physical and chemical characteristics, labeling, packaging, and safety.
Safety requirements are mandatory; according to these indicators, glassware that comes into contact with food is subject to mandatory certification. The requirements of this group include requirements for chemical safety (the migration of lead and cadmium is limited); to mechanical safety (chips, stuck pieces of glass, cutting and crumbling particles, through cuts and cut edges, foreign inclusions that cause damage to glass are not allowed), to water resistance and heat resistance; to the strength of fastening of handles and decorative elements.
In trade practice, quality control is usually carried out in terms of appearance, labeling compliance, and operability (checking the product in action).
When checking the appearance of SBT, defects may be detected that negatively affect various indicators of product properties. The impact of a particular defect on the quality of a product depends on the type of defect, its location, size, and the size of the product. Based on these criteria, some defects are allowed with restrictions on quantity and size, while others are not allowed.
Defects in glass products are divided into three groups: glass melt defects, production defects and processing defects.
Glass melt defects include:
– insufficient supply – occurs when there is an excess or lack of decolorizers or due to a violation of the glass melting process; appears as a greenish tint to the glass;
- gas inclusions - they are small (midges) and large (bubbles), in composition - airy or alkaline with a whitish coating, in location - internal and external squeezable;
– svil – well-vitrified thread-like or rope-like inclusions;
– schlier – transparent vitrified inclusions in the form of drops and tubercles;
– ruch – crystallized opaque particles.
Production defects include various deviations from standards that arise during the formation of products:
– variations in thickness in the walls, edges, and bottom of the product arise due to incorrect methods of molding products;
– edge scree – chips on the inner or outer surface of the edge of the product that occur when using low-quality grinding material;
– chips – differ from chips in that they extend from the edge along the plane of the product;
– notches – small cracks on the internal or external walls of the product;
– forgedness (traces from a worn mold);
– burrs and excesses (traces from opening forms);
– under-pressing (insufficient amount of glass melt), etc.
Processing defects include:
– overheated edges – heavily melted edges, often deformed;
– asymmetry of parts,
– stuck pieces of glass,
– bevel edge;
– dullness and erasure of the gold pattern, etc.
Checking the product in operation involves determining its integrity (the product is filled with water), stability, horizontal surface, mating of covers and plugs with the body and neck.
The marking must include the following information: trademark or name of the manufacturer; vendor code; mass fraction of lead (for products made of lead and high-lead crystal); GOST designation.
Containers and packaging must ensure the safety of products during transportation and contain the handling sign “Fragile. Carefully". Additional requirements for PBT packaging may be specified in agreements or contracts.
Current standards do not provide for the division of glass products into grades.

The technological process for the production of glass products is divided into the following main stages: preparation of glass melt, melting of glass melt, production of products, annealing, processing and cutting of glass products.

Preparation of glass melt consists of preparing raw materials, preparing the batch and melting the glass.

The raw materials used for the production of various types of glass are, with some convention, divided into two groups: main, or glass-forming, and auxiliary.

Glass-forming materials include silica, boric anhydrite, alumina, sodium sulfate, soda, potash, limestone, dolomite, red lead and litharge, witherite and zinc oxide.

Auxiliary materials include brighteners, decolorizers, dyes, opacifiers, oxidizing and reducing agents, and cooking accelerators.

Clarifiers help free the glass melt from large and small bubbles and make it homogeneous. Clarifiers include sodium sulfate, arsenic trioxide and nitrate.

Decolators are used to reduce or remove colored tints from glass. Arsenic trioxide, saltpeter, sulfate, sodium chloride, antimony oxide, etc. are used as bleaches.

Dyes are added during the glass melting process to color it a specific color. There are staining of glass with molecular dyes (oxides of heavy and light metals) and colloidal dispersion dyes (compounds of gold, silver, copper, selenium, antimony).

Silencers are used to make glass opaque. These are fluoride, phosphoric acid compounds, tin and antimony compounds. Mufflers paint the glass white.

Oxidizing and reducing agents are added during the melting of colored glasses to create an oxidizing and reducing environment. These include sodium and potassium nitrate, arsenic trioxide, carbon, tartar, and stannous chloride.

Melting accelerators help speed up glass melting (fluoride compounds, boric anhydride, aluminum salts).

All raw materials required for glass production are processed. Quartz sand is enriched, that is, the content of iron and other impurities in it is reduced. Then sand, soda, saltpeter are dried, dolomite, chalk, limestone are crushed and sifted through sieves - vibrators. After preparing the raw materials, they begin to compile the charge.

A charge is a mixture of raw materials in a given proportion. To speed up the cooking process, 25-30% cullet (of the same composition) is added to the mixture. The starting materials are thoroughly mixed and sent to glass furnaces for glass melting.

The main methods for producing household tableware include: blowing, pressing, press blowing and centrifugal casting.

Blow molding method production can be manual (for products of complex shapes) and mechanized. In the manual method, metal blower tubes are used, into which air is supplied with a special rubber cylinder. The heated end of the tube is lowered into glass melt, which adheres to the heated metal. A certain amount of glass is wound onto the tube, leveled on a metal table, and then inflated into a small bubble “jar”, ​​from which the products are finally blown into a metal split mold.

The mechanized method of blowing using a vacuum machine is used for glasses.

Pressing- a simpler way to produce products than blowing. The pressing process is as follows: a certain weight drop of glass melt is fed into a mold (matrix), into which a punch is lowered, exerting pressure on the glass melt as it moves, the latter filling the space between the mold and the punch. Products are pressed using manual, semi-automatic and automatic presses.

Press-blow method The production of products is carried out in two steps: first, the workpiece is pressed out and the edges of the product are trimmed, and then the workpiece is blown out with compressed air to the specified dimensions. The production of these products is carried out on automatic machines.

After the product is manufactured, it is sent for annealing. The annealing process for glass products for household use involves heating them and maintaining them at a temperature of 530-580°C. The products are then cooled to room temperature.

TO product processing This includes the separation of caps from blown products, processing of the edges and bottom of the product.

Decorations are applied to the bulk of blown glassware, i.e. they are cut. Products are decorated either during the production process (in a hot state) or when they are ready (in a cold state).

Decorations applied to glass products during their production process (in a hot state)

Colored glass obtained by adding dyes to glass melt.

Products with color made from a single layer of glass and covered with one or two layers of intensely colored glass.

Marble decoration obtained through the process of melting milk glass, to which ground, unmixed colored glass is added, thereby creating the impression of veins in marble. Glassware imitated with malachite is decorated in a similar way.

Decoration with fiberglass It is considered a promising type of decoration for products. Fiberglass fabric of a certain size is applied to an almost finished product, the fabric is fused to the surface of the glass, and the product is blown.

Decoration with colored mounds is as follows: the heated workpiece is rolled on a table over crushed colored glass, which envelops the workpiece and melts to its surface, after which the workpiece is heated again.

Guten work characteristic of products made by blowing without a mold. According to the artist's intention, the surface of the product may have indentations, bulges and clings.

Crackle decoration obtained when the workpiece is immersed in cold water, then heated in an oven and blown out. The surface of the product is covered with small and large cracks, creating a unique pattern.

Decoration with filigree or curling They give the product an openwork look and look like two or three colored spiral threads.

Chandeliers are obtained by applying solutions of organic metal compounds in organic solvents to the surface of products and subsequent firing. During firing, the solvents burn out, and a film of metals or their oxides is fixed on the surface.

The surface of products with cutting "irrization" has rainbow tints. The products are heated in a muffle furnace in a vapor atmosphere of a mixture of tin chloride, strontium nitrate and barium chloride, which, settling on the surface of the product, firmly connect with it and give various shades with iridescence (reminiscent of mother-of-pearl).

Decorations applied to finished products (cold)

All decorations applied to finished products (in a cold state) are done mechanically, chemically and by painting.

By mechanical means, matte tape, number grinding, diamond edge, engraving, straight wide edge are applied to the products.

Matte tape- This is the simplest type of decoration. A metal strip is pressed to the surface of the product, under which sand and water are fed; grains of sand scratch the glass, resulting in a matte stripe.

Number grinding is a pattern in the form of pits and grooves connected by inclined slits. The design is applied using sand, corundum and emery wheels.

Diamond edge- This is a carving on glass. The designs consist of deep slits and triangular grooves that form a complex geometric pattern. The diamond edge is applied using corundum and electrocorundum single- and multi-blade wheels sharpened at a certain angle. Then the product is polished.

Engraving— the design is flat, without large indentations, matte, often with a plant theme; The pattern is applied using copper or alundum disks of different diameters.

Straight wide edge is one of the types of cutting. It is applied to the products using cast iron or sand washers.

Chemical etching is applied to products: simple, complex (pantograph) and deep.

Simple and complex etching It is performed as follows: the product is covered with a mastic consisting of wax, paraffin, rosin and turpentine, then a pattern is drawn in it using a thin needle, after which the exposed glass surface is etched in a bath with hydrofluoric acid. Simple etching is characterized by a simple pattern; more complex patterns are applied on pantographic machines (complex etching).

Deep etching— performed on two- or three-layer glass manually with a brush. By repeated treatment with hydrofluoric acid, a relief pattern is obtained on the surface of the product.

Scenic drawings applied manually and semi-automatically with paints, 12% gold solution, enamels, chandeliers, followed by firing at a temperature of 580-600°C.

Chemical composition and properties of glass

Soda-lime-potassium, lead-potassium and borosilicate glass is used for tableware.

The approximate composition of glass is expressed by the “normal glass formula” R 2 O · RO · 6SiO 2, which is a trisilicate, and R 2 O means the monovalent oxides Na 2 O, Ka 2 O; RO - divalent CaO, MgO, PbO, etc., along with silicon oxides, the glass composition includes Al 2 O 3, Fe 2 O 3, etc. The most common glass compositions contain 14-16% monovalent oxides; divalent - 11-12% and silica - 71-75%.

There are chemical and physical properties of glass.

Chemical properties include the chemical resistance of glass, i.e. its ability to withstand the destructive effects of various environments and reagents. Glass is a chemically resistant material.

Physical properties of glass: viscosity, density, strength, fragility, hardness, heat resistance, etc. Viscosity for each type of glass at a certain temperature is a constant. The density of various glasses ranges from 2.2 to 6.0 (Mg/m³). Soda-lime glass has a density of 2.5, and crystal has a density of about 3.0 or higher.

The tensile strength of glass is low - from 35 to 90 MN/m², and in compression - from 500 to 2000 MN/m². Fragility - the property of glass to break under the influence of an impact load without plastic deformation. Glass has increased fragility; oxides MgO and Al 2 O 3 reduce it. Hardness is the ability of glass to resist the penetration of another body into it. According to the mineralogical scale, the hardness of glass is 4.5-7.5.

The thermal conductivity of glass is very low and ranges from 0.7 to 1.34 W/m deg. The thermal expansion of glass is characterized by a coefficient of linear expansion, which for various glasses ranges from 5.8·10 -7 to 151·10 -7 , for many glasses of mass use it is equal to 100·10 -7 . Thermal stability is the ability of glass to withstand sudden temperature changes without breaking.

The main optical properties of glass are transparency and the refractive index of glass. The transparency of glass depends on the chemical composition of the glass and the presence of iron oxides in it. The refractive index of glasses of various compositions ranges from 1.475 to 1.96; for ordinary glass it is 1.5, for crystal - 1.55 and higher.

Classification and assortment of glass products

Household glass products are classified according to the main characteristics: purpose, production method, type of glass, color, size, cutting method, completeness, etc.

By purpose household glass products are divided into five groups: household tableware; art products; household utensils, kitchen utensils; lamp products.

By production method Household glass products are divided into blown, pressed, press-blown and centrifugally cast.

By appearance glass products are sodium-potassium-lime (ordinary), potassium-lead (crystal) and borosilicate (heat-resistant).

By color they can be colored or with colors.

By size products are divided into small, medium, large and extra large.

The leading role in the creation of products is played by cutting, which provides ample opportunities for its decoration. Cutting is not always applied to products, and the desired effect is achieved by using only shape and color. The greatest variety in terms of cutting, of course, is found in blown utensils, and cuts on press-blow utensils are less interesting. Decorations are applied to the latter during the manufacturing process.

According to completeness household glass products can be piece or complete (sets and services).

The range of glassware, depending on the method of production and purpose, is divided into the following groups: blown products; pressed products; press-blow products; crystal products; household utensils; cookware.

Blown glassware is very diverse: its range includes hundreds of items. Blown glassware can be pieced or complete.

Assortment of pressed tableware significantly narrower than blown. Pressed products are distinguished by their simplicity of shape and decoration.

Press blow utensils has a limited range.

Household utensils include products used for preparing and storing food, pickles, jam, kvass, water, etc. (jars, bottles, barrels of various containers).

Kitchen utensils made of heat-resistant glass (borosilicate) and glass ceramics are intended for cooking. Its range includes: roasting pans, pots, pans and baking dishes.

Quality assessment of glass products

The quality of glass goods is influenced by many factors: design and dimensional features, mechanical strength, thermal stability, hygienic, aesthetic properties, etc. In terms of design and dimensional features, household glassware must correspond to approved samples. Products on a flat horizontal surface should not swing. Glass products must have good mechanical strength. The thermal stability of products is considered satisfactory if 99% of the tested products pass the tests provided for by GOST 30407-96.

It is necessary that glass products be transparent and not have colored tints (especially crystal). Products made of colored glass and colored glass must be uniformly colored.

It is important that the product has a clean, smooth surface without burrs or scratches and a clearly defined pattern. The edge of the product should not be cutting; for this it is melted, ground and polished.

In accordance with the current GOST, glass tableware and decorative items are produced in one grade. Crystal products are divided into grades I and II. When determining the grade of a product, the type of defect, its size, quantity and location are taken into account. On glass products there are defects in the glass melt, production and processing. The listed defects arise during the process of cooking, molding the product and its processing; they significantly reduce the quality of the finished product.

TO glass melt defects include the following:

1. Gas inclusions appear due to insufficient clarification of the glass mass. These include defects - midge and bubble. Cloudy and squeezable bubbles in the product are not allowed.

2. Svil, schlier are transparent inclusions that differ from the bulk of glass in chemical composition or physical properties. The strands are thread-like, hairy, in the form of nodules and strands.

3. Crystalline inclusions have a crystalline structure (white) glass particles.

Production defects formed during the formation of glass products. Variation in thickness in the walls and bottom of the product is the result of uneven distribution of glass melt during the production process of the product. Chips and nicks are damage with a conchoidal structure located at the intersection of the product with its end. Scree - small chips. Forging is an unevenness that manifests itself as fine waviness of the surface. Wrinkles are irregularities that appear as ripples on the surface. A fold is a pocket-shaped surface irregularity. Curvature, folds and wrinkles on products are not allowed.

Defects in processing and decoration of products are melting of the edges, asymmetry of the designs, imperfections and transfers on the products (allowed), breaks, obstruction of the diamond edge, blots, fading of paints and films, swelling, cracking, drips on the products are not allowed, since they sharply reduce the aesthetic and hygienic properties of the products. The total number of acceptable defects in terms of appearance in one product should be no more than 2 for small ones, 3 for medium ones and 4 for large ones. For especially large products, the total number of permissible defects that do not spoil the presentation is not regulated.

For crystal products, the total number of permissible defects in terms of appearance should not exceed 2 for small products of grade I, 3 for medium-sized products, and 4 for large products, and for grade II, respectively: 3, 4 and 5.

Labeling, packaging, transportation and storage of glass goods

Blown products are marked with a paper label, which is applied to the product indicating the manufacturer, trademark, GOST, pattern number, processing group.

Pressed and press-blow products are marked during production. The marking includes the name of the manufacturer or trademark.

Glass products are packaged in cardboard or corrugated containers with cavities or in bags made of wrapping paper or shrink film. When packaged in bags, blown products must be pre-wrapped in paper and interspersed with shavings or other materials. Shot glasses, glasses and other small and medium-sized products are wrapped in paper in pairs, placing paper between the bottoms of the products. Complete products are placed in one box or one bag. Souvenir and gift items are not wrapped in paper, but placed in specially artistically designed boxes. Paper bags tied with twine have a sticker label indicating: the trademark or name of the manufacturer; product name; pattern number or processing group; number of products per packaging unit (for group packaging); controller and packer number; packing date; designation of the standard.

Glass products are transported by rail in clean covered wagons or containers, on which the plant puts in large print the inscription: “Do not tilt the top!”, “Caution, fragile!”. When placing glass products in cars or containers, boxes and bags are placed tightly with packaging materials across two rows, without gaps. Products that are shipped to the Far North and other remote areas must be packaged in accordance with established standards and special requirements.

Glass products are stored indoors, protected from the influence of precipitation. When placing products in a warehouse, it is recommended to place heavy products on the lower shelves, located at a height of 15-20 cm from the floor, and lighter ones - on the upper ones.

The quality of the main groups of glass household goods (GBT) is standardized by GOST 30407-96, which applies to products made of ordinary glass and crystal and sets requirements for appearance, physical and chemical characteristics, labeling, packaging, and safety.

Safety requirements are mandatory; according to these indicators, glassware that comes into contact with food is subject to mandatory certification. The requirements of this group include requirements for chemical safety (the migration of lead and cadmium is limited); mechanical safety (chips, stuck pieces of glass, cutting and crumbling particles, through cuts and cut edges, foreign inclusions that cause damage to the glass are not allowed), water resistance and heat resistance; strength of fastening of handles and decorative elements.

In trade practice, quality control is usually carried out based on appearance, labeling compliance, and operability (checking the product in action).

When checking the appearance of SBT, defects may be detected that negatively affect various indicators of product properties. The impact of a defect on the quality of a product depends on its type, location, size, and size of the product. Based on these criteria, some defects are allowed with restrictions on quantity and size, while others are not allowed.

Defects in glass products are divided into three groups: glass melt defects, production defects and processing defects.

Glass melt defects include:

insufficient discoloration- occurs when there is an excess or lack of bleaching agents or as a result of disruption of the glass melting process, manifests itself in the form of a greenish tint to the glass;

    gas inclusions (bubbles)- they can be small (midges) and large, in composition - airy or alkaline with a whitish coating, in location - internal and external, pressable;

    svil- well-vitrified thread-like or rope-like inclusions;

    schlier- transparent vitrified inclusions in the form of drops and tubercles;

Rukh- crystallized opaque particles. Production defects include various deviations

from standards arising during the formation of products:

    thickness variation walls, edges, bottom of the product - arises due to incorrect methods of molding products;

    scree edges- chips on the inner or outer surface of the edge of the product that occur when using low-quality grinding material;

    chips - differ from chips in that they extend from the edge along the plane of the product;

    cuttings- small cracks on the walls of the product;

    forgedness(traces from a worn mold)

    hangnails And surplus(traces from drop-down forms)

underpressure(insufficient amount of glass melt), etc.

Processing defects include:

overflow of the edges- heavily melted edges, often deformed;

    asymmetry of parts;

    stuck pieces of glass;

    Kosina the edges;

    Matte and erasure gold drawing, etc.

Checking the product in operation involves determining its integrity (the product is filled with water), stability on a horizontal surface, and the mating of covers and plugs with the body and neck.

The marking must include the following information: trademark or name of the manufacturer;

vendor code; mass fraction of lead (for products made of lead and high-lead crystal); GOST designation.

Containers and packaging must ensure the safety of products during transportation and contain a handling sign “Fragile - be careful.” Additional requirements for PBT packaging may be specified in agreements or contracts. Current standards do not provide for the division of glass fiber products into grades.

4. Ceramic products

Ceramics is one of the oldest materials used for making dishes and other products. It has a number of positive properties: strength, heat resistance, environmental and chemical safety; products made from it have a high aesthetic potential, which determines its widespread use.

4 .1 General information about ceramics

Ceramics- these are products made of clay (or clay substances) with or without mineral additives, obtained by molding and subsequent firing. To improve consumer aesthetic properties, ceramics are coated with glaze.

Materials used in the production of ceramics are usually divided into plastic materials: clays (polymineral rocks consisting of kaolinites, soda, silicon oxides, feldspar, iron, etc.); kaolin (monomineral rock consisting of kaolinite); thinning materials- reduce shrinkage during drying and firing: quartz sand, alumina, broken porcelain and earthenware, fireclay; plavni - reduce the sintering temperature and create a glassy phase (feldspar and pegmatite); glaze materials.

The factors that shape the consumer properties and quality of ceramic household goods are the same as for glass products: the type of ceramics, the method of molding and the type of decoration.

Depending on the structure, a distinction is made between fine ceramics (vitreous or fine-grained shards) and coarse ceramics (coarse-grained shards). The main types of fine ceramics are: porcelain, semi-porcelain, faience, majolica, and coarse - pottery ceramics.

Porcelain- has a dense sintered shard of white color (sometimes with a bluish tint) with low water absorption (up to 0.2%), when struck it produces a high melodic sound, and can be translucent in thin layers. Due to the pair firing of the products, the edge of the side or the base of the product is not covered with glaze.

There are hard and soft porcelain. Hard porcelain is used for the production of tableware and tea and coffee tableware for everyday use. Soft porcelain can be: biscuit (not covered with glaze, used for the production of artistic and decorative products), bone (bone meal is introduced into the composition, externally resembles white marble, is characterized by high whiteness and transparency, used for the production of tea and coffee tableware for a festive assortment ), feldspathic (“thin-walled”, similar in properties and purpose to bone, but its white color has a bluish tint); low-temperature (“fritted” - heat-resistant, mechanically strong, usually coated with colored glazes, abroad one of the main types of ceramics for the production of everyday tableware).

The raw materials for the production of porcelain are kaolin, sand, feldspar and other additives.

Semi-porcelain in terms of properties it occupies an intermediate position between porcelain and earthenware, its shard is white, water absorption is 3~5%, it is used in the production of household utensils.

Faience has a white shard with a yellowish tint, the porosity of the shard is 9-12%. Due to the high porosity, earthenware products are completely covered with colorless glaze. The glaze has low heat resistance, so this type of ceramic is used in the production of tableware for everyday use. It is produced from white-burning clays with the addition of chalk and quartz sand.

Majolica has a porous crock (water absorption of about 15%), the products have a smooth surface, high gloss, small wall thickness (which is determined by the molding method - casting), they are covered with colored glazes, they can have decorative relief decorations. For the production of majolica, white-burning clays (faience majolica) or red-burning clays (pottery majolica), flux, chalk, and quartz sand are used.

Pottery ceramics- the shard has a red-brown color (red-burning clays are used), high porosity (water absorption up to 18%). Products can be covered with colorless glazes or painted with colored clay paints - engobes. The assortment includes kitchen and household utensils (pots for roasting, milk jugs) and decorative items.

The process of producing ceramic household goods in a simplified form can be represented by the following stages: preparation of raw materials; obtaining ceramic mass; product molding; drying and straightening; burning; glazing; decoration.

The main methods of molding ceramic products are: plastic molding method; casting, semi-dry pressing.

When molding products plastically They use ceramic mass with a moisture content of 22-24%, the formation is carried out on automatic or semi-automatic machines. With this method, the ceramic mass is placed on the bottom of the mold and rolled out with a template; a product is formed in the gap between the mold and the template. This method is used to produce products from hard porcelain, earthenware, and pottery ceramics.

Casting method involves the use of ceramic mass (slip) with a moisture content of 32-36% (creamy consistency), which is poured into porous gypsum or polyvinyl chloride molds. This method is used to produce products from soft porcelain (except frit), hard porcelain (products of complex shape), and majolica.

For flat products of simple shape use semi-dry pressing method. The ceramic mass has a residual moisture content of 2-3%; pressing is carried out in metal molds. This method is used in the production of products from earthenware, semi-porcelain, and low-temperature porcelain. The advantages of this method are an increase in production speed and a reduction in energy costs (drying and straightening processes are excluded), but it is used for a limited number of types of products: small plates, saucers, etc.

Ceramics are finally formed during the firing process. There are two types of firing: cozy And watered. Kiln firing precedes glazing, resulting in a shard that is resistant to soaking. Water firing is carried out after glazing in order to form the structure of the glaze.

At decorating ceramic household goods are used in a number of ways: painting, decorations in the form of stripes, stencil, silk-screen printing, decal. Specific types of decoration of ceramic household goods include the following:

    roof- coating the surface of the product with paints (distinguish between continuous; partial; with cleaning; with cleaning and finishing; downward and upward) using an airbrush, stencil, special templates;

    stamp- a small one-color surface pattern applied with paints and gold preparations using rubber stamps or tapes; it is usually used in combination with other types of jewelry;

    seal- a contour drawing formed by dots, dashes, strokes (ink from the print is transferred to the product, or first to tissue paper, and then to the product); monochromatic drawings, can be overglaze and underglaze, complemented by painting (with additional drawing), stencil;

    photo on ceramics- used for decorative (gift) products;

    decoration with decorative glazes: colored, flowing, crystal, matte, lace, luster, crackle.

    relief-cut decorations: openwork border, cut-out edge, relief border (and their combinations); decorative reliefs;

    additional decorations with paints and gold preparation: smear- continuous coating of the product element; motley- partial sketch (stroke) emphasizing individual elements of the product.

All drawings, based on the nature of their location on the product, are divided into side drawings; solid; bouquet (up to three sculptures); spreading with a large bouquet; medallion (a picture framed in the form of a circle, oval, polygon); arabesque (narrow side ornamental pattern).

Decorations can be overglaze and underglaze. Most types of surface film decorations; subject to firing.