Metalworking is a high-tech process. To get competitive products, you need to use high-quality equipment. One of the types of equipment that is used at the metalworking enterprise is drawing mills. There are different types of this equipment. The features of the units for drawing will be discussed later.
general description
Drawing mills are special equipment that is used during the processing of metals by pressure. They can be used to produce different products. The principle of operation of drawing mills is quite simple. A workpiece of a certain diameter extends through a hole of a smaller diameter. This work is done by rolls. They give the workpiece not only the required diameter, but also the shape.
As a result, the metal stretches and becomes thinner. The cross section of the product is round or shaped. The profile has high accuracy. Its surface is characterized by high purity. During the processing of metal, the workpiece may heat up. There is also cold drawing. The second option has several advantages. The finished product is stronger, harder. This increases the yield strength of its material.
Of great importance during metalworking is drawing. Drawing mills allow you to get a wire with a diameter of up to 5 microns. Pipes are also obtained on similar equipment. Their maximum diameter is 40 cm. The products of this industry are widely used in the national economy and industry.
Features
Modern equipment for drawing has a number of distinctive features. During the processing of metals, modern technologies are used. Therefore, today's mills are significantly different from equipment of past decades. First of all, their productivity increases. Modern mills are capable of producing much more products per unit of time. In this case, the surface quality of the metal will be good.
New equipment comes complete with dies, which are characterized by significant resistance to adverse effects and a long service life. Also, in modern units, various degrees of protection are provided. This significantly increases the safety of workers during the operation of the equipment. Precision processing is provided by modern measuring devices provided in the design.
Functional equipment
Modern drawing mills include a functional device and auxiliary equipment. The main part of the design is responsible for obtaining a specific processing result. Depending on the hauling device, the destination area of the mill is determined. Equipment can pull the workpiece in a straight line or wrap it around a drum. In the first case, several varieties of aggregates are distinguished. They can be tracked, rack and pinch, with reciprocating motion. Also on sale are units with a hydraulic mechanism for pulling a workpiece, chain drawing mills.
Also on sale are equipment with the function of winding the processed material onto a drum.
On the equipment, which involves pulling the workpiece in a straight line, produce bars, pipes, as well as other similar products. They do not wind up in riots.
The technology with the function of winding the wire is used to draw the wire. She may have a special profile. Also, pipes with a minimum diameter are made on such machines.
The presented equipment can be of the following types:
- one-time drawing (the workpiece is processed once);
- multiple with slip function;
- multiple with reverse tension;
- multiple without slip function.
For each type of finished product, the most suitable production methodology is selected. In the course of production, various metals and alloys are used. The technology of production depends on their type. The procedure involves several sequential steps.
Ancillary equipment
The drawing mill for the production of copper wire, steel pipes or other products necessarily includes a number of auxiliary mechanisms. It is intended to ensure the normal course of the production process. The category of auxiliary equipment includes unwinders, lubricating equipment, winders. Also, this category of mechanisms includes devices for sharpening wire, packaging riots, cutting blanks. In some cases, the material passing through the main equipment requires processing by welding.
In addition to equipment for drawing, the equipment may have a drum in its kit. The movement is carried out using an electric motor, gearbox. The design of a particular type of machine tool may differ depending on what material will be processed on it. Equipment for steel has a number of differences from units for non-ferrous metals. However, modern manufacturers produce equipment that is very similar, regardless of the type of metal.
It should be noted that its functionality depends on what material is processed on the machine. Non-ferrous metals are softer than steel. Therefore, the equipment that pulls them has a slip function. In this case, it is possible to reduce losses due to friction.
Principle of operation
It is necessary to consider in detail the principle of operation of the drawing mill. Material is fed into the unit from the basket of the front compartment. It goes through a series of roller devices. They direct the movement of the workpiece. Due to this action, the material is fed to the carriage roller. This is a compensating type device. After this, the workpiece falls on the drawing mill.
The presence of a compensating carriage in the system is extremely important. This helps prevent material breakage. Such trouble could not have been avoided by abrupt stopping or braking of the line. The operation of the carriage is quite simple. If for some reason the equipment stops abruptly, this device will rotate the rollers for some time. This allows you to give out some more material.
The compensating type carriage conducts an upward movement at this time. This allows you to release a certain amount of material. He enters the device for drawing. In this case, breaking the workpiece becomes impossible.
Further, the material enters the lower double drum. The cross over type roller holds the material higher. Here he takes the upper drum. If this is provided by the mechanism, the finished product is wound on a rod and stored here. It is from here that material is supplied when the mill stops, if it stops abruptly.
If necessary, after drawing, the products are straightened. She is given the necessary configuration. All work is provided by an electric motor.
Manufacturers
Today, the market for special equipment presents a huge selection of equipment for drawing. It is distinguished by functionality, performance and quality. In our country, equipment of Russian, Chinese and European production is most often purchased.
It is important to contact trusted suppliers. They will provide the necessary documentation for such devices. In this case, the equipment will have a guarantee. In this area, manufacturers of drawing mills from Europe will stand out. They produce the most modern, innovative technology. It provides many additional functions and modes. It can be either single mills or entire production lines. The quality of the finished product in this case will be the highest. This ensures that the products will be the most competitive.
Among European manufacturers of mills for drawing, German and Swiss-made equipment is in great demand. Depending on the type of equipment, the minimum cost of units is 1.5 million rubles. The most famous manufacturer in Germany in our country is Sket. Equally popular Swiss-made equipment. It is delivered to our country by ENCE.
For those enterprises for which the budget for the renewal of fixed assets is limited, it is possible to modernize the technical equipment using drawing mills in China. In this country, a huge amount of such equipment is produced. The minimum cost leaves from 1 million rubles.
Domestic manufacturers also supply similar units to the market. The cost of their products is comparable to Chinese. But the quality of the mills collected in Russia is higher. Also, some industries buy equipment that was in use. The price of such units starts from 50 thousand rubles. However, in this case, one should not count on the long-term operation of the equipment and the high quality of the finished product.
Single Draw Mill
Various types of drawing mills are on sale. They are intended for use in various technological processes. One of the popular types of products is a single-type mill. They allow the production of wire with a round cross-sectional diameter and a size of 25 to 40 mm. Also, pipes of ferrous and non-ferrous metals are made on such units. The larger the diameter of the finished product, the larger the drum is installed in the structure.
This type of wire drawing mill winds the wire onto the drum in one row. This reduces the weight of the riot.
Single mills provide a force of 0.05-200 kN. His choice depends on the type of finished product. At the same time, its cross-section, quality and profile are taken into account. Modern high-performance mills of this type provide a drawing speed of up to 5 m / s.
Productivity can be increased by increasing the mass of the riot. Moreover, this procedure is carried out both from the side of unwinding and winding the material. To do this, resort to a process such as welding.
One-time drawing is provided by equipment that includes an electric motor, gearbox, gearbox, unwinding figure, elevator, spike section and rack. The equipment stops only when it is necessary to change the receiving device when it is full. This procedure requires very little time. Maintenance and repair of drawing mills of this type is carried out only by specially trained personnel. The procedure does not take much time.
Double Draw Equipment
The wire drawing mill can crimp the workpiece twice. This allows you to give the workpiece the desired shape and size. Such equipment is used in enterprises with a small volume of metal forming. During such processing, the material undergoes four-fold reduction.
The simple design includes a two-stage drum. In the first stage, it has a smaller diameter. The slip function of the workpiece is often used here. The hood should be 1-2% larger than the difference in the diameters of these steps. At the lower stage, it is impossible to provide high compression. Therefore, in order to avoid wire breaks, the slip function is used here.
Also available are double-drag differential mills. They do not involve the use of slip on both steps. It is possible to carry out both high and low compression. Two drawing drums in a similar device are located on the same axis.
Repeated drawing
Drawing mills can crimp the workpiece several times. In this case, the material is pulled simultaneously through several fibers. This allows you to increase the degree of drawing of the workpiece. The draggs are sequentially located on the production line.
During processing, the drawing ratio is set. This indicator is affected by the initial size of the workpiece, its type of section and the parameters of the final product. Multiplicity can be set in the range from 2 to 25. There are camps that provide an even greater value of this indicator.
It is especially difficult to stretch durable materials. Behind the last drag in this case, there may not be enough tension. Therefore, to stretch the material through all the dies of the line at the same time is problematic. To enable such a treatment, a pulling drum is installed after each die. A workpiece is wound on it, and then it proceeds to the next processing step.
Direct-flow loopless units
Loop-free drawing mills require winding on the drum only a few turns of finished products (6-10 pcs.). This is enough to provide the required friction force. In this case, the strip extends along the line without slipping. Transportation is carried out without rollers.
Electric motors create anti-tension. The absence of a large number of rollers greatly simplifies the maintenance procedure, refueling the mill during pulling strong, thick workpieces. If significant compression cannot be used for the wire, this type of mills will allow to obtain high quality products using anti-tension.
The drums of the line are equipped with personal electric drives. They are connected in series. Moreover, in the process of tuning the torque, its excess determines the counter-tension index. The speed can only be adjusted on the drum, which feeds the finished wire. The remaining items are automatically configured.
Having considered the features and types of drawing mills, you can understand the principle of their work, as well as the features of the use of such equipment in production processes.