What is the grinder consist of. The scope of application

Editing a grinding circle: features, methods and rules

With prolonged work, the grinding circle is thinned and erased along the edge, which leads to a violation of its correct shape. This, in turn, negatively affects the work performed. Editing is required, which can be carried out in different ways. With its help, you can completely restore the structure of the grinding circle and extend its operational period without replacing it with a new.

The grinding circle consists of an abrasive surface, which is the interconnected fractional grains.

The distinctive features of the circles are determined by the scope of their use. With prolonged work, there is a possibility of flipping the end part, which leads to uneven grinding and can provoke damage to the details.

Soft circles are able to self.Ensure. When the surface layer is erased, new grains located under it enter the work. This does not affect the functionality of the circle itself.

Solid circles are deprived of this possibility due to suction and dulling. This is caused by a clog of the fractions of the circle by the wiped material. The grinding circle ceases to fulfill its functions and needs to be correct.

The appointment of grinding circles

The grinding tool is designed to remove the surface layer of the material in order to give the part of the specified geometric sizes or the required surface roughness. In addition, the direct grinding disk is used for peeping of cast blanks, stripping welds, as well as the removal of scale, rust and other contaminants from the surface of metal products. Various forms of grinding circles allow machining and grinding not only straight, but also curved surfaces. In this case, an abrasive tool can act as a template for the profile of the processed surface. Thin grinding is performed to give the surface of the product the required class of purity. To do this, use polishing discs with very small grain and soft ligament. Another area of ​​use of grinding circles is the sharpening of various tools: carpentry, locksmith and metal.Cutting, used on machines.

The use of grinding circles for metal processing

To grind hardened, not hardened, high carbon steels, grinding circles from an electric contribution with a granularity of 40 are used. 32, for stainless steel. From an electric contribution of white with a granularity of 40-32.

For processing aluminum, brass, bronze, circles are used, with an abrasive element. Black silicon carbide with Sic 95 content. 97% and granularity 40-32.

For processing solid alloys, grinding circles of green silice carbide with Sic 96 content are used. 98%.

What abrasive materials are used to create grinders?

The abrasive circle has a landing hole in the middle, which allows you to install it on the machine. Such circles are grinding and cutting. Grinding are used for grinding and sharpening parts and surfaces from durable materials. Such circles are made of particles of different sizes with the addition of binding components (volcanic, bakelite mass) by pressing in special forms.

Such abrasive materials are used to create grinders:

  • Silicon carbide. The circles of their material differ in black and green. Green carbide is more solid than black, but also more fragile. Such circles are suitable for working with fragile materials that can be deformed, crack due to corundum treatment (marble, porcelain) and grinding soft materials (rubber, aluminum, copper). Silicon carbide processed cast iron, granite, heat.Resistant steel.
  • Diamond. Diamond circles are used to work with different materials: metals, ceramic surfaces, marble, granite, onyx, glass, etc. With their help, cutting tools are pulled and finished grinding is carried out. Such a circle is self-terminated, it is fragile and due to the impact may be split into parts. Therefore, it is advisable to use it for finish processing, when you need to remove a small layer from the processed surface so that there is no threat of shock load. Due to low heat resistance, a diamond circle is best used with cooling.
  • Elbor. Characterized by high hardness and heat resistance. In terms of strength and hardness, it occupies the following place after the diamond, but is more fragile and less protected from mechanical influences (damaged when impact). Elbor is used to sharpen metal tools that can be deformed due to high temperature, and also for processing solid metals. This abrasive is widely used for finishing grinding of heat.Resistant, corrosion.Resistant steels.

In addition, electrocorundum is widely used to create grinders. This material is a clay molten in electric furnaces. The following varieties are distinguished:

  • Normal. It contains about 86-91 % of aluminum oxide. This type of electrocorundum is used to work with materials that differ in high resistance to break. This abrasive due to high viscosity is used for different friction loads. Due to good resistance to high temperatures and adhesion to the surfaces, uniform grinding is provided.
  • White, pink. This abrasive is up to 99% of aluminum oxide. Grinders from this material are finished processing of any steels, grinding threads. The white type of abrasive is inferior to the normal grain viscosity. Because of this, it is used for work, implying a lower depth of grinding. White corundure is more resistant to wear and high temperatures than normal.
  • Monocorund. Contains about 97% of aluminum oxide. Is the hardest and strongest type of electrocorundum. Devices for high.Speed grinding steel are made from it.

To purchase a diamond flexible circle or any means for processing stone, contact us. Our consultants will help you choose the best option, offer the best price and answer all questions.

The hardness of grinding circles

This definition is often misunderstood. The hardness of the mineral and device are different concepts. For the tool. This is the degree of resistance to the tear of grain from the base.

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According to the international certification system, the letters of the Latin alphabet are marked:

  • Group of the softest products. F, G.
  • Norm.Drying. H, i, j.
  • Medium.Tanks. K, l.
  • Medium. M and N.
  • Middle group. O, p, q.
  • Hard. R, s.
  • Completely hard. T, u.
  • Particular. V, W, X, Y, Z.

What is a grinding circle

Grinding circles are used both in industrial machines and in simple garage sharpeners, this tool is easy to work and significantly accelerates work on metalworking. But to achieve the best result, it is necessary to choose the right and use a grinding circle, which requires knowledge of existing types and features of this tool.

The grinding circles used today have a fundamentally identical device: in the general case, this is the body of rotation with a different profile, formed from an array of abrasive grains with a binder, and having a landing hole in the center for installation on a spindle (shaft) of a machine. The circle is made by gluing abrasive grains of a certain size using ligaments, which provide the necessary strength of the product and prevent its rupture under the influence of centrifugal forces during rotation.

Circles are classified according to the profile (cross section), type and granularity of the used abrasives, type of connecting material and some characteristics.

As abrasive material, the following types of grinding powders are used:

  • Elektrokorund (labeling “A”). Normal (grades 12A. 16A), white (brands 22A. 25A), chromium (brands 32A. 34A), titanium (brands 37A) and zirconium (brands 38a, can be marked with the letter “z”) ;
  • Silicon carbide (marking “C”). Black (brands 52C. 55C) and green (brands 62. 64C).

There are grinding circles in which diamond, elbrers and other materials are used as an abrasive, but they have a different design (a metal base on which the abrasive layer is applied) and the characteristics are not considered in this article.

The granularity of the abrasives used to make circles lies within the F36-F220 in accordance with GOST R 52381-2005 (corresponds to the international specification FEPA-Federal PRODUCERS OF ABRASIVES, the European Federation of Abrasives) and M10 according to GOST 3647-80 (currently time is partially canceled). In circles with abrasives F36. F220, the average grain size lies in the range of 58. 525 microns, and with abrasives M63. M10. From 7 to 63 microns.

When forming a grinding circle, the following types of ligaments can be used:

  • Ceramic (marking V, outdated. K);
  • Bakelite (marking B, B4, BF, obsolete. B, B4, BU);
  • Volcanic (marking r, outdated. C).

Ceramic ligaments. These are inorganic components based on various types of clay with additives of a field spar, quartz and other substances. After firing, the ceramic ligament provides a circle of the necessary rigidity, wear resistance and strength (including temperature), but it has increased fragility. These types of circles are not used in machines and machines leading with shock loads.

grinder, consist, scope, application

Bakelite ligament. This is a resin (bakelitis), which can be used in pure form, with strengthening additives (labeling BF/BO) or with graphite (marking B4/B4). Bakelite ligament due to elasticity is resistant to shock loads, however, it is poorly opposed to high temperatures and aggressive environments (including some types of lubricants and coolants, coolant. Also, a good self.Shaping circles on the bakelite bunch. Worn grain is relatively easily torn off the ligament, exposing a new grain, which provides stable abrasive properties.

Volcanic ligament. This is a vulcanized rubber (in fact. High density rubber or ebonite), which can have various additives to increase strength and chemical resistance. Currently, this type of grinding circles is used less often.

The higher the number, the less dense the structure has a circle, and the greater the distance in it between the grains.

Depending on the type of ligament and density, circles can have different hardness. A characteristic indicating the strength of retaining a bunch of abrasive grains. The higher the hardness, the stronger the grain is held in a bunch, and the more difficult it breaks out when the surface of the product is made by grinding. By hardness, the circle can be the following types:

  • Very soft (VM1, VM2; F, G);
  • Soft (m1. M3; h, i, j);
  • Medium.Tank (cm1, cm2; k, l);
  • Medium (C1, C2; M, N);
  • Medium hard (st1. St3; o, p, q);
  • Hard (T1, T2; R, S);
  • Very solid (TT; T, U);
  • Extremely solid (th; v. Z).

The digital-based marking of hardness complies with the old standard GOST 19202-80 (not used today), Latin letters-the standard GOST R 52587-2006.

Finally, grinding circles can have an accuracy class “AA”, “A” and “B”, and clock classes from 1 to 4.

Grinding circles are divided into several types by profile (section):

  • Type 1. Direct profile (PP);
  • Type 2. Ring (K);
  • Type 3. With a one.Sided conical profile (3P);
  • Type 4. With a bilateral conical profile (2P);
  • Type 5. With a one.Sided latch (PV);
  • Type 6. Cylindrical cup (CC);
  • Type 7. With a bilateral latch (PVD);
  • Type 10. With a bilateral latch and a hub (PVDS);
  • Type 11. Conical cup (Cheka);
  • Type 12, 14. Plate (t, 1t);
  • Type 20. With a sample;
  • Type 21. With a bilateral sample;
  • Type 22. With a sample and a back;
  • Type 23. With a sample and a latch on one side (PVK);
  • Type 24. With a sample and a latch on one side and with a back on the opposite side;
  • Type 25. With a sample and a back on one side and a sample on the opposite side;
  • Type 26. With a sample and a back on both sides (PVDK);
  • Type 35. End profile end;
  • Type 36. A direct profile with pressed fasteners (PN);
  • Type 37. Ring profile with pressed fasteners;
  • Type 38. With a one.Sided hub;
  • Type 39. With a bilateral hub.

All characteristics, geometric shape and sizes of grinding circles for stationary electric machines and machine tools in Russia are regulated by the standard GOST R 52781-2007. Previously, the standard GOST 23182-78 was valid for circles for handwriters, but at present it is canceled.


The operation and technical conditions of grinding circles regulates a number of Russian and international GOSTs. In particular:

  • GOST 3647-80 and corresponding to it ISO 8486. Regulates the granularity of circles.
  • GOST R 52588-2011-defines safety requirements for the tool.
  • GOST R 52781. Regulates the technical conditions of grinding circles.

There are other standards that determine the parameters of various types of grinding circles.

Types of grinding circles

There are various classifications of types of grinding circles based on their technical characteristics: in shape, according to the brand of an abrasive, by type of ligament, according to granularity. The totality of such parameters determines the type of processing for which this or that abrasive disk can be used. For industrial purpose, they are divided into grinding (for rough and thin grinding) and food (peeling). The former is used for all types of grinding and sharpening, and the latter is used for cleaning metal surfaces from various contaminants.


Abrasive discs used for mechanical processing, sharpening operations, polishing and polishing are generally called grinding. Basically, they are used to remove irregularities and reduce the roughness of surfaces on products from mineral materials and various metals. There are a large number of forms and sizes of such a tool, most of which are intended for grinding metal work. In addition to the most ordinary grinders with a direct profile, which are universally used to sharpen the tool and process flat surfaces, there are many other types of special forms. For example, plate circles are used to process the teeth of hounds and cutters, conical. For grinding threads, cups. For end grinding. There are also grinders for polishing work on flat and profile surfaces.


One of the varieties of rotational grinding tools is the circle. By this name, one can understand that they are used to clean the surfaces before the main mechanical processing or welding operations. These grinders have a direct profile (type according to GOST No. 1), and therefore another name of such a tool is a disk disk. They are used to process casting and welds, as well as for the removal of burrs, rust and old paintwork. If the food disk is used to remove crusts and scale from cast blanks and generations, then it is called peeling. In the process of work, reference circles are subjected to strong shock, so bakelite mixtures are used as a ligament in them.

Proven grinding manufacturers

The use of grinding circles suggests that in the process they account for a very serious load. Therefore, the quality of the products is given to special importance when choosing, because low.Quality circles are quickly cracking and destroyed.

Grounding manufacturers are represented on the market in large quantities, but not all products are of high quality.Nevertheless, you can find a fairly reliable and durable grinder among the products of both domestic and foreign factories.

Foreign production: suppliers

The production of grinding circles abroad is carried out in many countries, however, Italy occupies a special place among them. The manufacture of abrasive circles is engaged in companies such as:

  • Bavelloni, offering diamond and bakelite circles of various diameters for cutting glass and other tasks;
  • Boterro, offering circles both for rough grinding of glass (on a metallic basis), and for finishing grinding on a bake.Based basis, as well as diamond and bakelite products for machine tools and other products;
  • ADI is a recognized leader in the manufacture of cup circles designed to process the glass edge.

The operation of grinding circles of the production of Italian companies, as a rule, does not cause complaints, since they differ in extremely high quality and a relatively long service life. There is only one disadvantage in their use. High price.

For those who want to save on the purchase of a grinding circle, but not on its quality, the acquisition of Chinese.Made circles, in particular, companies will be an excellent solution: companies:

These circles are almost as long, like Italian, retain the properties of an sandpaper, but at the same time they are much cheaper.

Domestic manufacturers

Among the manufacturers of grinding circles in Russia are also companies whose products are in sustainable demand. Among them can be called:

The products of these and other Russian companies are successfully tested by high reliability and quite competitive price.

Grinding circles and abrasive materials

Types of grinding circles according to GOST R 52781-2007 are the following (rice. Eight.Thirteen).

As abrasive materials in circles, electrocorundum (a) and silicon carbide (C), Elbor and diamond are used in circles. Elektrokorund. Synthetic corundum (91–99% A1203) obtained by smelling of clay.Landing raw materials in electricity. SIC silicon carbide. Material obtained in electrical printing at high temperature. In pure form, sic are colorless crystals with diamond shine, but due to impurities they are usually painted in colors from yellow to black. Technical use distinguishes green and black silicon carbide.

Elboron circles according to GOST 241106-80 are widely used to grind hardened high.Speed steel, diamond circles in accordance with GOST 16181. 82. For sharpening of carbide tools.

In circles according to GOST R 52781-2007, which perform most of the metal processing, use electrorundant (A) and carbidromnia (C) materials on ceramic (V), bakelite (B), volcanic (R) ligaments:

grinder, consist, scope, application
  • – normal electrocorundum 15a;
  • – White Elektrokorund 23A, 24A, 25A;
  • – chromotitaneous electrocorundum 93A, 94A;
  • -Silicon-magnesium electrocorundum 91 A, 92A;
  • – Monocorund 43a, 44a, 45a;
  • – green silicon carbide 63C, 64C;
  • – black silicon carbide 53C, 54C, 55C.

Rice. Eight.Thirteen. Types of grinding circles according to GOST R 52781-2007

Circles Io GOST R 52781-2007 are made with granularities F36. F220 according to GOST R 52381-2005. The higher the grain number, the lower the grain size. When checking the powders for granularity, they are sifted through a set of five sieves. In each subsequent sieve, the size of the cell decreases. The sieve remains a certain volume of unenficed grains as a percentage of the initial volume of powder. To present about the sizes of cells and the remaining volumes in the table. Eight.1 shows the data for the largest grain used in circles F36, average F100 and small F220.

Grain composition of grinders with granularities F36, F100, F220

The size of the cell W2 Control Sita 2, MKM

The rest of the grinding powder Q Q2 on Kon “Troll Sita 2, %, no more

The size of the cell VF3 Control Sita 3, MKM

The balance of grinding powder (7, on a control sieve 3, %, at least

Cell size 1g4 Control Sita 4, MKM

The rest of the grinding powder in control sits is 3 and 4 %, at least

The size of the cell of the WJ Control Sita 5, μm

The balance of grinding powder in control sits 3-5 (2Z QA QS % at least

Earlier there was an idea that to improve the roughness of the processed surface, it is necessary to proceed to the use of circles with a reduced grain size, t.E. With a large grain number. It is currently proven that in circles with a large grain size, you can successfully receive good roughness due to a special amendment mode of circles.

The accuracy of the manufacture of circles should correspond to the uniform diameters by the unified norms for the tolerance of the size, radial and end beats without dividing into accuracy classes.

Three classes of imbalance are installed for circles. Class 3 should be used at the maximum operating speed of the circle up to 40 m/s, class 2. At a speed of 40-63 m/s, class 1. At speeds of more than 63 m/s.

The hardness of abrasive circles is indicated by the letters of the Latin alphabet with an increase in hardness from F to Z:

  • F, G. Very soft;
  • N, i, j. Soft;
  • K, l. Medium.Tanker;
  • M, n. Medium;
  • O, p, q. Medium hard;
  • R, s is solid;
  • T, u. Very hard;
  • V, W, X, Y, Z. Extremely solid.

The general rule of choosing the hardness of grinding circles is as follows: the higher the hardness of the processed material, the softer the circle should be.

The hardness of grinding circles is determined by four methods but GOST R 52710-2007 (rice. Eight.Fourteen).

Rice. Eight.Fourteen. Checking the hardness of abrasive materials

With the sandblasting method, a stream of quartz sand is directed to the surface of the tested circle under the pressure. By the depths of the resulting hole, they judge the hardness of the circle.


In the second method, a hardened ball is pressed in the surface of the circle of iodine with a certain load. The softer the circle, the deeper the hole. By the depths of the holes, they judge the hardness of circles.


When drilling, they reach a certain depth of the hole, the hardness is judged by the number of rpming drill.

The acoustic control method according to GOST R 52710-2007 gives an idea of ​​the hardness of the rate of spread of acoustic waves. The circle is installed in the “Sound” device and with the help of forced vibrations is brought to the state of resonance.

In the manufacture of circles between individual particles of an abrasive and a bunch, voids form. Pores (rice. Eight.Fifteen). Internal structure, t.E. Quantitative ratio and mutual arrangement of grains, ligaments and pores, are called structure of the grinding circle. The most important characteristic of the structure of the circle is the volume of grains in the material of the abrasive tool.

The metal chips formed during grinding should fall out of the pores when the circle exits from contact with the processed part. If the shavings lingers in the pores, then when contacted with the surface to be treated, it will heat up, melt and tightly clog pores, as a result, the cutting ability of the circle will decrease. This phenomenon is called Sawing circle.

Density structures are divided into closed, open and high.Porous. In Fig. Eight.15 schematically shows fragments of grinding circles of close grain, made with the same ligament, but having a different structure. White color belongs to pores, gray. Grains, black. Bunch. The denser the structure, the more grains per unit volume and less ligament and pores account. In the open structure, the number of pores in the circle is larger, and abrasive grains are located further from each other. In highly porous circles, the pores are so great that they are superior to the volume of dense material. Through a high.Porous circle of tens of millimeters, you can freely blow the air.

Technology Production of a grinding circle

Grinding wheels and surface finish.

A grinding circle is a device designed for cutting, polishing and milling materials such as, for example, glass or metal. The principle of work of the grinding circle is the same as that of the grinding machine. It is based on the friction of the particles of abrasive on the surface of the processed material. In the process of grinding, the circle is self.Adjusted. This is because abrasive particles break down, forming new sharp particles.

The grinding circle is made of several mineral and chemical components. The composition of the grinding circle depends on what action it is intended for, whether it is cutting, polishing or grinding, and for which materials it will be used. If you need a grinding circle for metal work, then it includes abrasive particles based on the white electrocorund. If a grinding circle is designed for cutting non.Metallic objects, such as stone or cement, abrasive particles based on silicon carbide, or carborund (sic) are used.

The scales programmed by the computer automatically weigh the components of the future mixture. These are impurities and additives, such as mineral cryolita and iron oxide, which lubricate abrasive particles. All components of the mixture combine powder and liquid resins together. The first components entering the mixer is powdered resin and additives. A minute later, they add liquid tar and abrasive materials to them. All this is thoroughly mixed for 5 minutes until the mixture in the consistency will resemble raw sand.

In order for the mixture to become absolutely homogeneous, it is sifted through a special sieve, separating lumps. Further, the mixture is poured into round forms using a device called “shuttle”. The diameter and depth of the form depends on the model of the grinding circle. The bottom of the form is reinforced with fiberglass.

A ring made of galvanized steel is installed in the center of each form. It fixes the mixture in four places. It is specially designed to protect the shaft rotating the grinding circle from damage. Then the product is squeezed by a hydraulic press. The pressure on it is about 350 kg/cm2, equivalent to pressure 30 cars. After the grinding circle leaves the conveyor, it is necessarily weighed to make sure of its compliance with technical standards.

Weighing, circles are sent to the oven. The temperature in it per day increases from 20 ?From to 200?With. Thanks to this, the resin hardens, thereby combining the components of the mixture. After the oven, the grinding circles get already hard, like a stone.

The final stage in the production of a grinding circle is the labeling of the label. Grinding circles move along the conveyor, periodically stopping. At this time, a nozzle is lowered on them, from which 8 drops of hot glue are produced onto the circle, and then the label is glued. It describes the parameters of the circle, the maximum speed of rotation, the scope of its application and, of course, the manufacturer’s logo is depicted. Then the circles are turned to the other side, where the label is glued indicating the safety rules.

The diameter of the grinding circle varies from 5 to 50 centimeters and more, thickness is 1-12mm. The smallest grinding circles are used in road bodybuilding, and the largest can cut railway rails or other large items.

Types of grinding circles

To properly process the part, it is necessary to determine the type of grinding. This will allow you to choose the right abrasive nozzles. The main selection criteria are the material of the processed part and the nature of the impact on its surface.

So, grinding circles with a straight or ring profile are widely used in everyday life and on small machines for grinding metals, sharpening operations performed by their end surface. These circles are relevant when working with glass, porcelain, stone (here you can also use flat nozzles with one- or bilateral extinguishing, which are convenient in the carrying out of the partitioning work).

The most common include conical circles, which can be both bilateral and ordinary. They can be used for all of the above work to process the surface of parts with the plane. Also, with their help, it is possible to perform recesses in almost any materials.

For processing many details, the best options can be called a grinding cup circle and a circle with plaster nozzles (most often they have all.Metal nozzles and diamond spraying). The cup circle resembles a direct profile tool with a conical latch. The main difference is that the end is located at right angles to the side plane.

Assortment of abrasive circles by the type of abrasive is quite wide. In addition to the previously mentioned diamond coating, electrocorundum is widely used. With the help of electric contribution, whole nozzles are made. Most often they have no reason and a pressed core.

The circles made of silicon carbide are also in demand. The latter are divided into two types: black and green (nozzles have the corresponding color). Green at the same time is more fragile.

High.Strength abrasives include Elbor. This material is based on cubic nitride boron. In terms of operational properties, it is not inferior to the diamond, while the elbor is characterized by a higher level of thermal resistance.

grinder, consist, scope, application

Circles from abrasive petals on a fabric base

Circle of the spellbird petal has a fan location of abrasive tissue petals. High elasticity, good adaptability to the processed surface made a petal grinding circle popular in metalworking and when grinding carpentry products. Until recently, the petal circle was used only on grinding machines and a direct grinding machine. Relatively recently, Klingspor began to produce petal circles for an angular grinding machine with a diameter of 115 and 125 mm. The new WSM617 petal circle is called like a petal corner circle. The petal grinding circle has an advantage over fiber and self.Supporting grinding circles that they do not cause the formation of secondary burrs, they are not clogged with grinding products.

Lipstand grinding circles are widely used in a metal.Processing sector when processing pipes. Grinding circles with dissected lamellas are suitable for processing shaped metal or wooden products.

The grinding circle is an important and significant abrasive tool that allows you to solve all possible problems on grinding machines and manual grinders. A user who wants to get the best result needs to take into account all the factors and features when choosing a suitable grinding circle.

The submitted types of grinding circles meet the requirements of GOST and are absolutely safe to use. You can buy a grinding circle in an abrasive complex on favorable terms.

Characteristics of grinding circles and their marking

There are different types of this tool. They differ in a number of parameters: sizes, shape, hardness, granularity. The selection of a grinding circle in shape and size depends on the specifics of the work. Flat tools can have a conical and direct profile, as well as tucks on one or two sides. Their shape is disk, plate, ring or cup.

An important characteristic is hardness. It depends on how durable the binding element is. Abrasive grains themselves have high firmness. Their location and ratio with the binding substance determines the structure of the adaptation.


The granularity of the grinding circle is determined by the size of abrasive grains of emery, diamond, and others. The unit of its measurement is micron. Uniform size. High quality of the tool, t. To. Provides better surface treatment. The choice of a circle with the required granularity depends on:

  • Details in need of processing and its size;
  • The thickness of the layer that must be removed;
  • Degree of roughness that is planned to give the processed surface.

According to this parameter, the marking is carried out respectively to two systems. The first of them was used in Soviet times. According to the then acting GOST (3647-80), a numerical designation was used. A grinding circle with grain size 10 micron was indicated by the number 1. If the size was 400 microns, then the number 4 was placed.

Currently, the designation is made, respectively, GOST 52381-2005, which repeats the international system. It uses letter designations. The dimensions of the grains are indicated by the letter F with the number, while the higher it is, the lower the size. For example, the F40 designation suggests that the size of the grains is 400-500 microns, and the F70 is about 200-250 microns.

GOST R 52381-2005 Abrasive materials

The petal grinding circles differ in that the working segments on them are located at the edges and resemble the petals. Their granularity depends on which work they are intended for. For rough processing, circles with large grains are used, mainly from emery, and vice versa.

Types of abrasive compositions

Grinding circles are made from materials that meet a number of requirements. First of all, they must have high hardness and not be subjected to friction wear. As well as a low thermal conductivity indicator. Industry uses various abrasive compositions. The main ones are the following.

  • Spherocorund. It is a material containing spherical grains and molten aluminum oxide. The hardness of this composition is high, the granularity is rough. Therefore, it is used for solid alloys.
  • Monocorund. It differs in that the grains in it have a monocrystalline structure. This composition is used in processing products from heat.Resistant and instrumental alloys. It is distinguished by reliability and durability.
  • Carbide.Based electrocorundum. The composition for working with details that have passed heat treatment (cast iron, various alloys, non.Ferrous metals), from which it is required to remove the surface layer. She is not afraid of temperature drops.
  • Boxite.Based electrocorundum. This composition has high heat.Resistant properties and the level of hardness.

The desired composition is selected taking into account the features of the work to be performed. And also the quality of products that need to be processed. Only in this case can the desired result be obtained

Hardness indicators

The firmness of grinding circles is their ability to prevent staining with grains when used before they completely develop their resource. This indicator is not determined by the firmness of abrasive grains. It depends on the technology of manufacturing the circle itself, the ligament, shape and type of particles, emery, granularity.

When interacting with the surface of the product, self.Substitution occurs: cutting grains of diamond or emery during grinding are split, some of them are painted. As a result, the new ones come into effect in return for the dulled. By hardness, such tools are divided into hard, soft, medium. In addition, very soft and very solid, medium.Span and medium.Sized, and extremely solid. Less solid are characterized by greater ability to self.Interference. In practical activities, grinding circles with an average hardness indicator are more often used. They are resistant to resistance and high performance.

Before starting use, it is necessary to determine the technical features in order to accurately choose the most suitable. For example, if it is necessary to sharpen a tool with cuts from solid alloys, you should choose a soft circle with a high ability to self.Substitution. If you need to achieve forms with the highest possible accuracy, then solid models with graters made of emery or diamond are more suitable.

TOP-3 petal disks for grinding

In circles for grinding Bosch X-Lock X571 At the heart of the petals of zirconium and aluminum.

  • The material is perfect for prolonged and intensive work with metal.
  • The X-Lock disk mounting system provides ease of replacing the circle during operation.
  • Among the “pluses” of the model, it is necessary to note a strong base and the enhanced design of the petals.
  • Bosch will help to easily polish the metal, working even with a large load.

The Russian master RM90337 is more complicated, but it has proven itself perfectly even when working at a speed of more than 13 thousand. Rpm.

  • Fiberglass is laid at the base of the circle, which ensures the resistance of the material to wear.
  • The design of the petals provides comfortable work.
  • As abrasive material, zirconium oxide is used, which does not overheat and is not afraid of washing.
  • Professionals recommend using a grinding circle Russian master when working with aluminum, brass, bronze.

Dronco 5211384 consists of cotton and polyester, which indicates the flexibility and stamina of the material.

  • At the heart of the grinding disk. A glass network that allows the use of a circle at a large load.
  • Dronco does not leave scratches, so the circle is used in decorative work. Recommended for the final stage of grinding.

Having studied the characteristics of various circles for grinding, you can easily choose the perfect disk at an affordable cost.

Abrasives for grinding circles

Materials whose properties are suitable for use as abrasives are mined (natural abrasives) or created at chemical industry enterprises (artificial abrasives). They are crushed by crushing, cleaned with electromagnets and chemicals, and heat treatment is subjected to. The finished abrasive material is sorted by classes. It is sifted in installations equipped with a cascade of grill and nylon nets with different sizes of cells. Grain, prevailing in the elongated material in volume, mass and quantity, is considered the main fraction.

Under the terms of GOST 3647-80, there are four types of the main fraction of grinding abrasives-grinder in size from 160 to 2000 microns, grinding slices in size from 40 to 125 microns, a micro-grinder size of 14 to 63 microns and a thin micro-grinder size of 3 to 10 microns. It should be borne in mind that the grinding material consists not only of the main fraction, but also with grains of other sizes, large or smaller. By the total volume of abrasive-grinding material, its grain composition is determined. There are two types of grain composition: the grain composition by weight, determined by the weight of all grains of the same size within the fraction to the total weight of the material; grain composition by the number of grains, calculated by the number of grains of all fractions separately for the total number of grains in the material.

The granularity meaning grain size in the main fraction in relation to groups of materials for grinding is indicated as follows:

  • For grinds and grinds. 1/10 part of the width of the sieve cell in MKM, through the lumen of which the grain of the main fraction does not pass. An example of the designation is 25, 40 or 18, meaning the size of abrasive particles 250, 400 and 180 microns;
  • For micro.Grinders. An extremely large grain size within the boundaries of the main fraction (in MKM), indicating the numbers of the Litera “M”. Example. M10, M40, M24;
  • For diamond grinders and grinds. The number in the form of a fraction, the numerator of which is equal to the width of the upper sieve cell, and the denominator indicates the width of the cell of the lower sieve that prevents the sifting of the grains of the main fraction (numbers in microns). For example. 160/125, 400/315;
  • For diamond submicroporos and microporos. The number in the form of a fraction, in the numerator of which the maximum size of the grain of the main fraction is indicated, and in the denominator. The minimum size (in MKM). Example. 28/20, 40/28, 12/9.

Also, the composition of abrasive particles is estimated by the percentage of the grain of the main fraction in the total volume. High (“B”), increased (“P”), normal (“H”) and permissible (“D”). For example, with granularity M63-M5, the main fraction should be no less than “B”-60-55%, “P”-50-45%, “H”-45-40%.

Characteristics of grinding circles

The ability to withstand forces striving to violate the rigid bonds between the bunch and grain of the abrasive is called the hardness of a circle for grinding. There are two ways to evaluate hardness. The effect of a sandy stream (hole method) and pressing under a given load of a steel ball. Consider the scale of brands assigned to the abrasive product according to the results of tests for hardness:

  • VM1 and VM2. Very soft;
  • M1, M2 and M3. Soft;
  • Cm1 and cm2. Medium.Tanks;
  • C1 and C2. Medium;
  • ST1, ST2 and ST3. Medium hard;
  • T1 and T2. Solid;
  • Tue. Very solid;
  • Th. Extremely hard.

The numbers that accompany the letter designation inside most degrees indicate an increase in hardness. For example, in order to increase the hardness of a grinding circle to one degree, it is necessary to increase the volume of the ligament by 1.5%.

In terms of total volume, the structural ratio of abrasive grain, ligaments and pores as part of the tool is indicated by number. From 0 to 20 (in the first case, the volumetric concentration of abrasive particles corresponds to 62%, in the second. 22%). As the license plate grows, the volumetric amount of grains is reduced. By 2% with each number. The relative concentration of grains in diamond grinding instruments is also indicated as a percentage, but somewhat differently. The above number four often exceeds the actual content in the grinding material tool. 75, 100, 150, etc.P.

Type of circle for grinding, brand of abrasive grain, circle dimensions, granularity index, structural number, type and brand of ligament, as well as other parameters indicate a static characteristic. The condition of the tool at the time of delivery. In circles with a diameter of more than 250 mm, the static characteristics data are set at the end, on products of smaller sizes. From 40 to 250 mm. Information are indicated on the packaging (packages or boxes).