Modern methods of processing non-ferrous metals.

In addition to the above methods of processing metals and manufacturing blanks and machine parts, other relatively new and very progressive methods are also used.

Metal welding. Before the invention of metal welding, the manufacture of, for example, boilers, the metal hulls of ships, or other work requiring the joining of metal sheets to each other, was based on the application of the method rivets.

At present, riveting is almost not used, it has been replaced metal welding. A welded joint is more reliable, lighter, faster and saves metal. Welding work require less cost work force. Welding can also be used to join parts of broken parts and, by welding metal, to restore worn parts of machines.

There are two welding methods: gas (autogenous) - with the help of a combustible gas (a mixture of acetylene and oxygen), which gives a very hot flame (over 3000 ° C), and electric welding at which the metal is melted by an electric arc (temperature up to 6000 ° C). At present, electric welding has the greatest application, with the help of which small and large metal parts are firmly connected (parts of the largest hulls are welded together). sea ​​vessels, bridge trusses and other building structures, parts of huge boilers of the highest pressure, machine parts, etc.). The weight of the welded parts in many machines is currently 50-80% of their total weight.

Traditional metal cutting is achieved by removing chips from the surface of the workpiece. Up to 30-40% of the metal goes into chips, which is very uneconomical. Therefore, more and more attention is paid to new methods of metal processing based on waste-free or low-waste technology. The emergence of new methods is also due to the spread in mechanical engineering of high-strength, corrosion-resistant and heat-resistant strong metals and alloys, the processing of which is difficult by conventional methods.

New methods of metal processing include chemical, electrical, plasma-laser, ultrasonic, hydroplastic.

At chemical treatment chemical energy is used. The removal of a certain layer of metal is carried out in a chemically active environment (chemical milling). It consists in time and place controlled dissolution of metal from the surface of workpieces by etching them in acid and alkaline baths. At the same time, surfaces that cannot be processed are protected with chemically resistant coatings (varnishes, paints, etc.). The constancy of the etching rate is maintained due to the constant concentration of the solution.

Chemical processing methods produce local thinning on non-rigid workpieces, stiffeners; winding grooves and cracks; "waffle" surfaces; handle surfaces that are hard to reach for the cutting tool.

At electrical method electrical energy is converted into thermal, chemical and other types of energy directly in the process of removing a given layer. In accordance with this, electrical processing methods are divided into electrochemical, electroerosive, electro-thermal and electromechanical.

Electrochemical processing is based on the laws of anodic dissolution of metal during electrolysis. When a direct current passes through the electrolyte, a chemical reaction occurs on the surface of the workpiece included in the electrical circuit and is the anode, and compounds are formed that go into solution or are easily removed mechanically. Electrochemical processing is used in polishing, dimensional processing, honing, grinding, cleaning metals from oxides, rust.

Anode-machining combines electrothermal and electromechanical processes and occupies an intermediate position between electrochemical and electroerosive methods. The workpiece to be machined is connected to the anode, and the tool is connected to the cathode. As a tool, metal disks, cylinders, tapes, wires are used. Processing is carried out in an electrolyte environment. Workpiece and tool
set the same movements as in conventional machining methods.

When a direct current is passed through the electrolyte, the process of anodic dissolution of the metal occurs, as in electrochemical processing. When the tool (cathode) comes into contact with microroughnesses of the processed surface of the workpiece (anode), the process of electroerosion occurs, which is inherent in electrospark machining. The products of electroerosion and anodic dissolution are removed from the processing zone during the movement of the tool and the workpiece.

EDM is based on the laws of erosion (destruction) of electrodes made of conductive materials when a pulsed electric current is passed between them. It is used for flashing cavities and holes of any shape, cutting, grinding, engraving, sharpening and hardening tools. Depending on the parameters of the pulses and the type of generators used to obtain them, electroerosive machining is divided into electrospark, electropulse and electrocontact.

Electrospark processing used for the manufacture of dies, molds, cutting tools and for hardening the surface layer of parts.

Electropulse processing used as a preliminary in the manufacture of dies, turbine blades, surfaces of shaped holes in parts made of heat-resistant steels. In this process, the metal removal rate is approximately ten times greater than in electrospark machining.

Electrocontact processing is based on local heating of the workpiece at the point of contact with the electrode (tool) and mechanical removal of the molten metal from the processing zone. The method does not provide high accuracy and surface quality of parts, but gives high speed removal of metal, therefore, it is used when cleaning the ebb or rolled products from special alloys, grinding (roughing) body parts of machines from hard-to-cut alloys.

Electromechanical processing associated with the mechanical action of an electric current. This is the basis, for example, of electro-hydraulic processing, which uses the action of shock waves resulting from a pulsed breakdown of a liquid medium.

Ultrasonic processing of metals- a kind of mechanical processing - is based on the destruction of the processed material by abrasive grains under the impact of a tool oscillating with an ultrasonic frequency. The energy source is electrosonic current generators with a frequency of 16-30 kHz. The working tool punch is fixed on the waveguide of the current generator. A blank is placed under the punch, and a suspension consisting of water and abrasive material enters the processing zone. The processing process consists in the fact that the tool, oscillating with an ultrasonic frequency, hits the abrasive grains, which break off the particles of the workpiece material. Ultrasonic processing is used to obtain hard-alloy inserts, dies and punches, cutting out figured cavities and holes in parts, piercing holes with curved axes, engraving, threading, cutting workpieces into parts, etc.

Plasma-laser methods processing is based on the use of a focused beam (electronic, coherent, ionic) with a very high energy density. The laser beam is used both as a means of heating and softening the metal in front of the cutter, and to perform the direct cutting process when piercing holes, milling and cutting sheet metal, plastics and other materials.

The cutting process proceeds without the formation of chips, and the metal evaporating due to high temperatures is carried away by compressed air. Lasers are used for welding, surfacing and cutting in those cases where the quality of these operations is subject to increased requirements. For example, a laser beam cuts over hard alloys, titanium panels in rocket science, nylon products, etc.

Hydroplastic processing metals is used in the manufacture of hollow parts with a smooth surface and small tolerances (hydraulic cylinders, plungers, wagon axles, electric motor housings, etc.). A hollow cylindrical billet, heated to the temperature of plastic deformation, is placed in a massive detachable matrix, made according to the shape of the part being manufactured, and water is pumped under pressure. The workpiece is distributed and takes the form of a matrix. Parts made in this way have a higher durability.

New methods of metal processing bring the technology of manufacturing parts to a qualitatively higher level. high level compared to traditional technology.

Heat treatment is a set of processes of heating metals to a given temperature, holding and cooling in order to give the workpiece certain physical and mechanical properties as a result of a change in the structure (internal structure) of the part. Material for blanks - non-ferrous metals, steel.

The main types of heat treatment:

1. Annealing of the 1st or 2nd kind. In the process of heating metals to a certain temperature, after holding and cooling, an equilibrium structure is obtained, viscosity and plasticity increase, hardness and strength of the workpiece decrease.
2. Hardening with or without polymer transformation. The purpose of heat treatment is to increase the parameters of strength and hardness of the material due to the formation of a non-equilibrium structure. It is used for those alloys that undergo phase transformations in the solid state during heating and cooling processes.
3. Vacation. Durable steels, hardened metal alloys are subjected to it. The main parameters of the method are heating temperature, cooling rate, holding time.
4. Aging applies to alloys that have been quenched without a polymorph. After hardening, the strength and hardness of magnesium, aluminum, nickel, and copper steels increase.
5. Chemical-thermal treatment. The technological process changes the chemical composition, structure and surface properties of parts. After processing, wear resistance, hardness, fatigue resistance and contact endurance, anti-corrosion resistance of the material increase.
6. Thermomechanical processing. This type includes the process of plastic deformation, with the help of which an increased density of defects (dislocations) of the crystalline structure of the workpiece is created. This method is used for aluminum and magnesium alloys.

Welding, electrical and turning processing

Welding is the production of a permanent connection of a steel part by heating to melting or to a highly plastic state. During processing, the material melts along the edge of the parts to be joined, mixes and hardens, and a seam is formed after cooling. There are electric (arc or contact) and chemical (thermit or gas) welding.

Turning method of processing - handmade on special machines in order to remove the excess layer and give parts certain shapes, roughness, accuracy, dimensions. The main types, depending on the purpose of the work: basic, repair and assembly.

To electrical methods metalworking includes:

1. Electrospark method. This method is based on the phenomenon of destruction of strong metals under the action of electric spark discharges.
2. Ultrasonic method. Precious stones, hard alloys, hardened steel and other materials are processed with the help of special machines.

metal casting

The technological process of casting consists in the fact that parts are obtained after pouring molten metal into certain forms. Various materials are used:

• cast iron;
• steel;
• copper, magnesium, aluminum and zinc alloys.

Today, metalworking equipment has found wide application in various industrial sectors: the railway industry, energy, aircraft and shipbuilding, construction, mechanical engineering, and so on.

The choice of machines directly depends on the volume of production (mechanical, manual, CNC, automatic, and so on), required quality details and processing.

Turning and milling

Machining is used to produce new surfaces. The job is to destroy the layer certain area: the cutting tool controls the degree of deformation. The main equipment for the mechanical processing of metals are turning and milling machines, as well as universal turning and milling machining centers.

Turning is a metal cutting process carried out with a linear feed of the cutting tool while simultaneously rotating the workpiece.

Turning is carried out by cutting a certain layer of metal from the surface of the workpiece using cutters, drills or other cutting tools.

The main movement in turning is the rotation of the workpiece.

The feed motion during turning is the translational movement of the cutter, which can be performed along or across the product, as well as at a constant or varying angle to the axis of rotation of the product.

Milling is a metal cutting process carried out by a rotating cutting tool while simultaneously linearly feeding the workpiece.

The material is removed from the workpiece to a certain depth with a cutter that works either with the end side or the periphery.

The main movement in milling is the rotation of the cutter.

The feed motion in milling is the translational movement of the workpiece.

Turning and milling of metals is carried out using universal machining centers with numerical control (CNC), which allow performing the most complex high-precision processing without taking into account human factor. CNC assumes that each stage of the work performed is controlled by a computer, which is given a specific program. Processing a part on a CNC machine ensures the most accurate dimensions of the finished product, because. all operations are performed from one setting of the workpiece being processed.

EDM

The essence of the method of electrical discharge machining (cutting) is the beneficial use of electrical breakdown in surface treatment.

When the electrodes under current approach, a discharge occurs, the destructive effect of which is manifested on the anode, which is the material being processed.

The interelectrode space is filled with a dielectric (kerosene, distilled water or a special working fluid), in which the destructive effect on the anode is much more effective than in air. The dielectric also plays the role of a catalyst for the process of material decay, since it - when discharged in the erosion zone - turns into steam. In this case, a "microexplosion" of steam occurs, which also destroys the material.

The most important advantage of wire-cutting machines is the small radius of the effective section of the tool (wire), as well as the possibility of precise spatial orientation of the cutting tool. Because of this, there unique opportunities for the manufacture of precise parts in a wide range of sizes with a fairly complex geometry.

For some manufactured parts, the use of electrical discharge machining is preferred over other types of machining.

EDM wire-cutting machines allows you to rationally carry out operations on:

production of parts with a complex spatial shape and increased requirements for accuracy and cleanliness of processing, including metal parts with increased hardness and brittleness;

production of shaped cutters, matrices, punches, cutting dies, patterns, copiers and complex molds in tool production.

Waterjet

Waterjet metal processing is one of the most high-tech processes with high accuracy and environmental friendliness of production. The waterjet cutting process consists in processing the workpiece with a thin jet of water under high pressure with the addition of an abrasive material (for example, the finest quartz sand). The technological process of waterjet cutting is a very accurate and high-quality method of metal processing.

In the process of hydroabrasive processing, water is mixed in a special chamber with abrasive and passes through a very narrow nozzle of the cutting head under high pressure (up to 4000 bar). The waterjet mixture exits the cutting head at a speed greater than the speed of sound (often more than 3 times).

The most productive and versatile equipment is console and portal type systems. Such equipment is ideal, for example, for the aerospace and automotive industries; it can be widely used in any other industries.

Waterjet cutting is a safe processing method. Cutting with water does not produce harmful emissions and (due to the possibility of obtaining a narrow cut) economically consumes the processed material. There are no zones of thermal influence, hardening. The low mechanical load on the material facilitates the processing of complex parts, especially those with thin walls.

One of the most important advantages of water jet technology is the ability to process virtually any material. This property makes waterjet cutting technology indispensable in a number of applications. technological productions and makes it applicable in almost every industry.

laser processing

Laser processing of materials includes sheet cutting and cutting, welding, hardening, surfacing, engraving, marking and other technological operations.

Usage laser technology processing of materials provides high productivity and accuracy, saves energy and materials, allows you to implement fundamentally new technological solutions and use hard-to-cut materials, improves the environmental safety of the enterprise.

Laser cutting is carried out by through burning sheet metal laser beam. During the cutting process, under the influence of a laser beam, the material of the section being cut melts, ignites, evaporates or is blown out by a gas jet. In this case, narrow cuts with a minimum heat-affected zone can be obtained.

This technology has a number of obvious advantages over many other cutting methods:

the absence of mechanical contact allows processing brittle and deformable materials;

materials from hard alloys can be processed;

high-speed cutting of thin sheet steel is possible;

For cutting metals, technological installations are used based on solid-state, fiber lasers and gas CO 2 lasers operating both in continuous and repetitively pulsed radiation modes. A focused laser beam, usually controlled by a computer, provides a high concentration of energy and allows you to cut almost any material, regardless of their thermal properties.

Due to the high power of laser radiation, high process productivity is ensured in combination with high quality cutting surfaces. Easy and relatively simple control of laser radiation allows laser cutting along a complex contour of flat and three-dimensional parts and workpieces with a high degree process automation.

Machining is a process during which the dimensions and configuration of workpieces and parts are changed. If we talk about metal products, then special cutting tools are used for their processing, such as cutters, broaches, drills, taps, cutters, etc. All operations are performed on metal-cutting machines according to the technological map. In this article we will learn what are the methods and types of mechanical processing of metals.

Processing methods

Machining is divided into two large groups. The first includes operations that occur without removing the metal. These include forging, stamping, pressing, rolling. This is the so-called using pressure or shock. It is used to give the desired shape to the workpiece. For non-ferrous metals, forging is most often used, and for ferrous metals, stamping is most often used.

The second group includes operations during which part of the metal is removed from the workpiece. This is necessary to give it the required size. Such mechanical processing of metal is called cutting and is performed using the most common processing methods are turning, drilling, countersinking, grinding, milling, reaming, chiselling, planing and broaching.

What is the type of processing

The manufacture of a metal part from a workpiece is a laborious and rather complicated process. It includes many various operations. One of them is mechanical processing of metal. Before starting it, make up technological map and make a drawing of the finished part indicating all the required dimensions and accuracy classes. In some cases, a separate drawing is also prepared for intermediate operations.

In addition, there is roughing, semi-finishing and finishing machining of metal. For each of them, the calculation and allowances are performed. The type of metal processing as a whole depends on the surface to be treated, the accuracy class, the roughness parameters and the dimensions of the part. For example, to obtain a hole according to the H11 grade, rough drilling is used with a drill, and for a semi-clean reaming to the 3rd accuracy class, you can use a reamer or countersink. Next, we will study the methods of mechanical processing of metals in more detail.

Turning and drilling

Turning is performed on machines of the turning group with the help of cutters. The workpiece is attached to the spindle, which rotates at a given speed. And the cutter, fixed in the caliper, makes longitudinal-transverse movements. In the new CNC machines, all these parameters are entered into the computer, and the device itself performs the necessary operation. In older models, for example, 16K20, longitudinal and transverse movements are performed manually. On lathes it is possible to turn shaped, conical and cylindrical surfaces.

Drilling is an operation that is performed to obtain holes. The main working tool is a drill. As a rule, drilling does not provide a high accuracy class and is either rough or semi-finishing. To obtain a hole with a quality below H8, reaming, reaming, boring and countersinking are used. In addition, after drilling, internal threading can also be performed. Such machining of metal is performed using taps and some types of cutters.

Milling and grinding

Milling is one of the most interesting ways of metal processing. This operation is performed using a wide variety of milling cutters on milling machines. There are end, shaped, end and peripheral processing. Milling can be both rough and semi-finishing, and finishing. The smallest quality of accuracy obtained during finishing is 6. With the help of cutters, various dowels, grooves, wells, undercuts are machined, profiles are milled.

Grinding is a mechanical operation used to improve the quality of roughness, as well as to remove an excess layer of metal down to a micron. Usually, this processing is the final stage in the manufacture of parts, which means it is finishing. For cutting, they are used on the surface of which there is a huge number of grains that have different shapes. cutting edge. During this processing, the part is very hot. In order for the metal not to be deformed and not chipped, cutting fluids (LLC) are used. Machining of non-ferrous metals is carried out with the help of diamond tools. This makes it possible to provide best quality manufactured part.

Metalworking means technological process changes in forms, quality characteristics and mechanical properties of steels and other materials to achieve the required performance. Modern technologies processing of hard and super-hard workpieces allows to produce products of exceptional quality at minimal production costs.

Despite all this, the industry continues to evolve steadily. To date, one can distinguish 3 key areas in the development of metalworking:

• development of new alloys and materials for their processing;
• increasing the efficiency and productivity of the process;
• optimization of metalworking methods.

Metal processing technologies

All metalworking technologies can be divided into 4 categories:

A significant proportion of metal products is manufactured by casting molten steel, cast iron, bronze, aluminum, copper, magnesium, zinc into special forms. This method is used for the production of housings for heating radiators, pumps and gearboxes, and frames for industrial machines. In the vast majority of cases, the casting process is accompanied by milling and boring processing of working and clamping surfaces.

Pressure treatment

This group of metalworking methods includes: pressing, rolling, stamping, drawing, forging. As a rule, the impact of pressure is aimed at changing the shape and size of a metal workpiece without destroying its properties and structure. However, before applying any mechanical force, it is often necessary to increase the ductility of the metal. This can be done by heating it to certain temperature indicators, determined by its chemical composition.

Soldering technology is used to obtain permanent connections. The essence of the method is to heat the metal to the melting point. To date, there are 6 types of welding:

• chemical;
• thermal;
• gas;
• electrical;
• arc;
• contact.

1. Machining on machine tools for metal

   For the manufacture of parts of the required geometric shapes and sizes, metal cutting technology is used on special machine equipment according to pre-designed drawings. To date, this is the most common option for processing workpieces made of steel, copper, brass, gold, silver, etc. Metal-cutting machines include turning, milling, engraving, planing and grinding machines.

   For the processing of thin sheet metals, laser cutting technology is used. An optical laser beam burns the metal along a predetermined cutting line. This method allows you to perform high-precision processing.

   Another method of modern machining of metals is waterjet cutting. Its principle is to act on the workpiece with a thin water jet with particles of abrasives. Water is supplied under high pressure, due to which abrasive substances destroy the material in the impact zone literally by molecules. Waterjet cutting is widely used in those enterprises where safety regulations prohibit strong heating and the formation of sparks.

   And finally, one of the safest and most high-speed methods of cutting metal is plasma cutting. It allows you to accurately, cleanly and accurately cut rolled products of any thickness at any angle. Plasma is formed from a gas with the participation of an electric current. The temperature of such a jet can reach 30,000 degrees. Plasma cutting suitable for processing any metals: non-ferrous, ferrous, refractory.