Diamond is a natural mineral that is carbon with an allotropic crystal lattice. Due to the peculiarities of the molecular structure, it is an extremely hard material that can be stored indefinitely.
The chemical composition of a diamond can be changed under the influence of various factors: high temperature, pressure and / or vacuum. As a result of their action, diamond turns into another chemical element, graphite, which has a different composition of qualitative characteristics.
Diamonds are produced by natural mining and artificial mining. In the framework of the second method, the chemical element graphite is subjected to high temperature and pressure. Graphite material changes its molecular structure and turns into diamond raw materials, acquiring the characteristic properties of strength.
Before further use, the resulting raw material needs additional processing. Factor increased diamond hardness requires a special approach to the methods of its implementation.
Story
The history of diamond mining is extremely young. This is due to the complexity of the search and extraction of the mineral, as well as the difficulties associated with its processing. The processing technology of the described material with the help of another diamond began to gain popularity only by the XIV-XV century of our era. Until this time, this method was used only by ancient Indian masters, who carefully kept the secrets of technology.
On the territory of Russia, the development of mineral deposits and the development of its processing technologies took industrial scale only in the second half of the XIX century. Today in Siberia, work is underway on the extraction of this mineral in the mines that are on the list of the largest in the world. At the same time mastered all types of diamond processing.
Processing features
The processing technology and a set of technical devices suitable for this are determined by the name of the ultimate goal for which the processed diamond will be used.
The characteristics of the diamond necessitate its use in various technological systems, tools and devices. For example, a small diamond fraction, a crumb, is used as a spray coating covering the working surfaces of any cutting devices. Diamond spraying is used for application to cutting discs, saws, bands, intended for sawing metal, stone, concrete, ceramics and other materials.
Despite the stability of diamond to the effects of destructive loads of a wide spectrum, he is a fragile material. The use of percussion-pressing technology makes it possible to crush diamonds into chips. Mineral crushing is performed using a hydraulic press (this treatment option is rarely applicable).
The most widely used technology is rolling milling. As part of this process, the raw material is conveyed through a conveyor to a special chamber in which cylindrical rollers in contact with each other rotate. Passing between them, the rough diamond crumbles. Considering the coefficient of diamond strength, several blocks with rotating rollers with different gaps between them are used on the conveyor. This allows you to reduce the load on the mechanism, as it is a phased crushing on the principle of more to less.
The working surface of the rollers is covered with diamond coating, since no other material is able to withstand this load in such an effective equivalent.
The dimensional parameters of the crumb fraction are determined by the name of the end goal for which it will be used. Diamond grit larger grain is used for rough processing of materials with high strength factor: ceramics, granite, porcelain. For example, large crumb is used as a cutting element applied to the working edge of circular crowns for cutting round holes in hard materials: ceramic tile, concrete, granite slabs and others.
The diamond crumb of smaller granularity is applied to implementation of thin processing of these or those materials. In the framework of this treatment, materials are cleaned, polished and polished. Polishing is performed with a special paste, which is based on diamond dust. Obtaining diamond chips of different grain sizes is achieved by crushing and subsequent sieving.
Passing crushed diamond through mesh panels with different cell sizes makes it possible to obtain fractions of a fixed diameter.
The process of obtaining diamond materials suitable for use in production purposes is a more laborious procedure than the shock-pressing technology. As these materials are used, for example, circles for cutting glass, tips of turning tools and others. They are elements consisting entirely of diamond mass. Making such additions involves carrying out production procedures associated with resource costs and the use of several processing technologies at the same time.
The properties of diamond strength make it difficult to manufacture parts that place high demands on dimensional parameters and shape accuracy.
The only material with which you can produce efficient processing of rough diamonds is diamond itself.
The correct combination of factors affecting the processing tool and the material being processed allows for the most efficient processing. For example, in some cases, the workpiece is heated within the average temperature range, and the temperature of the processing device is kept in the area of low thermal performance. In this case, the preheated workpiece can be processed, and the percentage of tool wear is reduced.
The use of this method is due to the properties of diamond, which it acquires under the influence of high temperatures. The higher the temperature, the lower the coefficient of strength of the mineral.
How to make a split?
Another way to process a diamond is with hot iron. This mineral is able to enter into a chemical reaction with the metal heated to high temperatures. Hot iron begins to absorb the carbon component of the diamond. At the point of contact of the hot metal with the mineral, at the molecular level, the latter melts.
This method has low production efficiency, however, only with its help it is possible to achieve certain results in the processing of diamond material.
The application of the hot steel method is carried out when it is necessary to cut large volumes of raw materials with a minimum waste ratio. The method uses hot steel wire driven by rotating shafts. In this case, the cutting line is as thin as possible, and the loss of the main raw material is minimized.
With the hot sawing method, only manipulations can be performed that are aimed at processing a general nature. Detailed cutting is performed using more sophisticated grinding techniques.This method also uses hot drilling technology. In this case, the drilling steel element is also heated to high temperatures. The efficiency of the method is also increased by heating the two parts as a result of friction against each other.
Diamond drilling is used for roughing. Along the split line of the workpiece, holes of the desired diameter are drilled. Special anchor expanders are immersed in them. The technology allows you to manage the expansion of anchors alternately or simultaneously. Because of this, it is possible to perform a controlled split of the workpiece along a given line.
The key role for the effectiveness of the method is played by the angle at which the holes are drilled. Any deviation from the specified values can lead to a breakdown accuracy.
What are polished diamond?
The main direction in the processing technology of this mineral is its grinding. Thanks to this procedure, diamonds acquire their final form, and in some cases turn into precious stones.
Making diamonds, the masters resort to methods of step-by-step processing. Rough stock is cleared of impurities of other minerals, if any. Then rough cutting is performed, thanks to which the main form of the future product is formed. After this, the cut begins.
For grinding a diamond mineral, devices are used that are equipped with special nozzles — discs or plates that have a thickness, shape, and material of manufacture that correspond to the name of the procedure being performed. The working surfaces of these nozzles are coated with diamond particles of various diameters.
If the cut is made in order to obtain a gemstone - a diamond, then a lot of nozzles with a wide range of dimensional parameters are used. The first used plates or discs with diamond grit of the largest diameter. As the process proceeds, the granularity of the nozzles decreases. The final polishing is carried out using diamond nanoparticles.
The tools used to cut are different in purpose and principle of operation. Some of them function due to the presence of rotational motion of the rotor, on the end shaft of which a grinding disk is attached. The work of other tools is based on the principle of reciprocating movement. Grinding plates are inserted into special clamps of these tools.
During processing, the diamonds are ground to a transparent glassy state. Due to the fact that the edges of the future diamond are located in strictly adjusted positions, and at a given angle, the rough material is transformed into a precious stone. At the last stage of processing it is polished to a mirror state.
The reproduction of the whole process takes a huge amount of time (sometimes years), which is explained by the resistance of the mineral to external effects.
Interesting information about diamond mining and processing can be found in the next video.
