Body car

04/11/2012 0:50 85

Body car - This is a complex and metal consumer part of the vehicle, which serves to accommodate the driver, passengers and cargo. Not only appearance depends on the state of this element. carBut also important parameters like streamlining, comfort and safety.

Modern Body car Usually make a frameless. It is a rigid welded construction consisting of:

basis (floor) with special subframes for installation transmissions and engine;

front and rear parts;

left and right sidewall;

rear and front wings;

roofs.

Elements of final finishing of the body include:

bumpers (Protect the front and back of the body in collisions at low speeds);

outdoor decoration and protective decorative lining (used to improve the aerodynamic characteristics of the car);

body glazing;

door locks (play a significant role in ensuring passive safety);

seat (provide passive and active safety);

interior decoration.

When designing a body, the manufacturer takes a number of factors: size and type of engine, dimensions of leading bridges, the space required for installation of wheels, the volume and location of the fuel tank, aerodynamic characteristics, road clearance, visibility, comfort and safety during operation, manufacturability, maintainability and much Other. The resulting design should have as many rigidity as possible when crashes and bending, the low frequency of oscillations, well absorb the kinetic blow energy during the accident, and also be resistant to the effects of constant stresses, which can lead to cracks and the destruction of welds. The main condition for satisfying these requirements is the right choice of materials used in the manufacture body car.

At the moment, the greatest popularity was obtained:

a) Plonic steel steel.

The shell carrying "skeleton" of the car is made of thin-sheet steel (0.6 to 3 mm). Due to its high strength, plasticity and economic efficiency, no other materials of large distribution in the production of bodys did not receive.

b) aluminum.

Aluminum is usually used in the manufacture of individual parts of the body (hood, lid trunk, etc.) in order to reduce the mass of the car. However, sometimes used for the manufacture of carrier parts, such as in the ASF spatial frame of the German company Audi.

c) Plastics.

The use of plastics instead of steel in the manufacture of individual body elements recently becomes more and more popular. The advantages of this material are very low cost and simplicity of manufacture, minuses - low strength and impossibility of repair (damaged item has to change).

To protect the metals from corrosion, the amount of flange compounds, as well as sharp edges and angles, the zones of possible accumulation of dust and moisture are eliminated as much as possible, the zones of the possible accumulation of dust and moisture are eliminated, special technical holes are performed for anti-corrosion treatment, the ventilation of the hollow elements is provided, drainage holes are performed.

Three main differences body type: single-vocabulary (engine compartment, salon and trunk are combined into one), two-volume (in one compartment there is an engine, driver, passengers and luggage) and three-volume (in one compartment there is an engine, in the second - driver and passengers, in the third - Luggage compartment). In addition, the body of passenger cars is distinguished by the number of doors (two-, three-, four-five-door), according to the number of seats (with one, two or three rows) and the roof design (with open or closed riding).

Materials from which produce the body of a modern car

The overwhelming majority of the bodies of modern cars are made from the same material that Henry Ford used to produce its legendary Model T. However, in order to reduce the weight of the vehicle, automakers not only use such well-known metals as aluminum, magnesium and all sorts of alloys, but also invested in the development of new materials, including fiberglass ( fiberglass) And all kinds of carbon fiber options.

Consider some of the main modern materials, on the example of creating a sports car.

Carbon

In the automotive industry, the most advanced from the technological point of view from the materials used today is carbon. The name of this composite material translated from Latin Carbonis means "coal". The base of carbon is the threads of carbon, which have outstanding capabilities: the characteristics of resistance to stretching-compression, as in steel, while the density, and, accordingly, the mass, less than that of aluminum (for comparison, with the same strength of carbon 40%, it became easier and By 20% aluminum), moreover, carbon has a minimal expansion when heated, high wear resistance and chemical resistance. But, naturally, carbon cannot be perfect and its threads are designed only for stretching, and therefore be used as reinforcing material. For use in the bodies and panels of cars, the alloy is used, and more precisely the modified fiber - rubber threads in the threads of the carbon. Such carbon fiber is still used to make carbon-ceramic brake discs and clutch discs, due to the fact that they are much more resistant to overheating and have the ability to maintain performance at higher than steel discs, temperatures. It is not surprising that initially applied carbon invented in Formula 1 in the seventies (Mercedes McLaren, Porsche Carrera GT).

Aluminum

The second most popular material in the production of supercars - aluminum, more precisely, its alloys. The advantage of such alloys is that they are easy and, moreover, practically not subject to corrosion. Aluminum alloys are used in the manufacture of motor blocks of cylinders, outdoor body panels, the most carrier body and some suspension elements. Why use aluminum instead of steel? Because of its lightness, such designs are much easier to be the same, but from steel. However, aluminum has its drawback and is associated with its welding: The fact is that the welding process must be produced in the medium of inert gases using a special additive wire. Therefore, some automakers (for example, Lotus) are trying to seek the replacement of welding and glue aluminum parts with a special composition, enhancing the joints of the junctions with rivets.

Plastic

In the production of sports cars, all sorts of plastic received widespread use. Especially durable and elastic plastic is used for the manufacture of body panels, in some models (for example, Chevrolet Corvette) - the entire outdoor part of the body. In such a car, the carrying design is performed in the form of a framework, which is hosted by a decorative body.

Fiberglass

Fiberglass is a fiber or complex thread that is formed from glass. In this form, the glass shows unusual properties for himself: it does not be afraid and does not break, but instead it is easy to short without damage. It allows you to go from it fiberglassused in the automotive industry.

Due to the fact that the glass fabric can take any form, it is used primarily when creating aerodynamic kites. Using the glass molding layout, the necessary form (framework) is given, and resins are used to fix it. Thus, it turns out an easy and durable carcass of the sports car body.

Tomorrow

The automotive industry, as well as any other, does not stand still and develops in favor of the consumer who wants to have a fast and safe car. This will lead to the fact that in the future, more new materials that meet modern requirements will be used.

In the car body, a huge number of different materials are used, much more than in any other knot of the car. Now we will look at what the bodies of the car are manufactured and for which these or other materials are used.

To accurately comply with all technology, strength standards and at the same time make the body easy and cheap manufacturers are constantly looking for new materials.

Consider the main advantages and disadvantages of various materials.

Of the steel now make the main elements of the car. Basically, low carbon sheet steel thickness from 65 to 200 microns is used. Unlike earlier cars, their modern counterparts have become much easier, while maintaining the rigidity and strength of the body.

In addition to lowering the weight of the car, low carbon steel allows you to make parts of various complex forms, which allowed the designers to implement new ideas.

Now to disadvantages.

Steel is very susceptible to corrosion, so modern bodies are treated with complex chemical compositions and paint according to a certain technology. Also, the disadvantages include high material density.

The body elements are empty from the sheets of steel, and then weld into one. Today, welding is fully carried out by robots.

Advantages of steel bodies:

* cost;

* Easy to repair the bodies;

* Well-established production technology.

Disadvantages:

* High mass;

* The need for anti-corrosion processing;

* a large number of stamps;

* limited service life.

Aluminum

Aluminum alloys are not so long used in automotive production. You can find cars, where only part of the body elements aluminum, but there are also fully aluminum bodies. The feature of aluminum is the worst noise insulating ability. To achieve comfort, you must additionally conduct noise insulation of such a body.

Welding with argon or laser is required to connect body elements from aluminum, and this is a more complex and expensive process than when working with more familiar steel.

Advantages:

* The form of body parts can be any;

* smaller weight with equal strength equal;

* Corrosion resistance.

Disadvantages:

* Difficulty in repair;

* High welding cost;

* more expensive and complex equipment during production;

* Above the cost of the car.

Fiberglass and plastic

Fiberglass is a fairly widespread concept, which combines any material consisting of fibers and soaked with a polymer resin. Carbon, fiberglass and kevlar received the greatest distribution. From these materials, the body panels most often make.

Polyurethane is used in the details of the cabin, trim and in shockproof linings. Recently, the wings, hoods and trunk lids make from this material.

6.2. What makes the body of cars

None in any other element of the car is not used so many diverse materials as in the body. These are structural, finishing, insulating and other types of materials.

Basic parts of the body are made of steel, aluminum alloys, plastics and glass. Moreover, the preference is given to low carbon leaf steel with a thickness of 0.6 ... 2.5 mm. This is caused by its high mechanical strength, deficiency, the ability to deeply extract (it is possible to obtain parts of a complex form), the technological content of the welding parts and so on. The disadvantages of this material are very high density (therefore body is obtained heavy) and low corrosion resistance requiring complex and expensive protection events.

Aluminum alloys are used in bodyworking still in limited quantities. Since the strength and rigidity of these alloys is lower than that of body steel, therefore, the thickness of the parts have to increase and a significant reduction in body weight cannot be obtained. In addition, the noise insulating the ability of aluminum parts is lower than steel, and more complex activities are required to achieve the necessary acoustic characteristics of the body. Considering the high thermal conductivity of the material and formation on its surface of aluminum oxides with a high melting point, for welding aluminum parts it is necessary to use more powerful and expensive equipment.

Nevertheless, examples of widespread use of aluminum in passenger car bodies are known. Back in the 50s. In France, a Panar-Dina car was produced with an aluminum alloy body, and later the Citroen ZXS-19 car. Had an aluminum roof. There is reason to believe that, as the physicomechanical properties of aluminum alloys improve, solutions to technological and other issues, these materials will take a worthy place in body-building buildings.

About 80% of plastics used in cars accounted for five types of materials: polyurethanes, polyvinyl chlorides, polypropylene, ABS plastics, fiberglass. The remaining 20% \u200b\u200bis polyethylene, polyamides, polyacrylates, polycarbonates, etc.

From fiberglass manufactures outdoor bodies of bodyworks, which ensures a significant reduction in the mass of the car. Thus, the body of the car "Corvette" Models of 1984 by 113 kg is easier than steel.

From polyurethane foam, pillows and backrests of seats, shockproof lining, etc., are made by a relatively new direction to the use of this material for the manufacture of wings, hoods, trunk covers, etc.

Polyvinyl chlorides are used for the manufacture of many fittings (devices, handles, etc.) and upholstery materials (fabrics, mats, etc.). From polypropylene make headlights, steering wheels, partitions and much more. ABS plastics are used for various facing parts.

The number of glass in car bodies is steadily increasing. This is explained by the desire to improve visibility, give a car more aesthetic appearance. Inorganic glasses are mainly used. The transparency depends on the quality of surface treatment (non-polished or polished), and mechanical characteristics - from heat treatment (uncrowed or hardened). After hardening the glass can not cut or drill. In case of impact, it is crushed into small pieces with stupid edges, so such glass is called safe. Tempered glass has a thickness of 3 ... 6 mm.

Safe glasses can be obtained by gluing, for example, two sheets of inorganic thin glass with a transparent film of polymethylacrylate or full acetate. It turns out a horse skamer, called triplex. With a strong impact, such glasses disintegrate into fragments held on an intermediate layer with a thickness of 0.4 ... 0.8 mm. (Glasses with a thicker intermediate layer have high strength when bending and shuffles.)

Organic (polymeric) glasses have high transparency, easily painted, are able to delay infrared rays - (prevent the heating of the salon with sunbeams). However, they possess a very significant disadvantage - easily scratched. Move such glasses from polycarbonate or methyl methacrylate.

Throughout history, from the moment the car was created, the search for new materials was kept. And the body of the car was no exception. Produced body bodies, steel, aluminum and various types of plastic. But on this searches did not stop. And, for sure, everyone is interesting, from which material do car body do today?

Perhaps the manufacture of the body is when creating a car with one of the most complex processes. The plant in the factory, where the body is produced, covers an area of \u200b\u200bapproximately 400,000 square meters, the cost of which is a billion dollars.

For the manufacture of the body, you need more than a hundred separate parts, which then need to be combined into one structure connecting all parts of the modern car. For lightness, strength, safety and minimum body value, designers need to make compromises all the time, look for new technologies, new materials.

Consider the shortcomings and advantages of the main materials used in the manufacture of modern car bodies.

Steel.

This material is used for the manufacture of bodyworks for a long time. Steel has good properties, allowing to produce parts of various shapes, and with the help of various welding methods to combine the necessary parts into a whole design.

A new grade steel has been developed (reinforcing during heat treatment, doped), allowing to simplify production and further obtain the specified body properties.

Body is manufactured in several stages.

From the very beginning of the manufacture of steel sheets having different thicknesses, separate details are stamped. After these parts are welded into large nodes and with the help of welding are assembled into one. Welding in modern factories lead robots, but also manual types of welding are also used - semi-automatic in carbon dioxide environment or contact welding is used.

With the advent of aluminum, it was necessary to develop new technologies to obtain specified properties that steel bodys should be.

Tailored Blanks technology is just one of the new products Welded on a template Steel sheets of various thicknesses from a variety of steel grades form a stamping workpiece. Thus, individual parts of the manufactured part have plasticity and durability.

low cost,

high maintainability of the body,

exhaust production technology and disposal of body parts.

the biggest mass

corrosion protection is required,

need for a large number of stamps,

their high costs

as well as a limited service life.

Everything goes into business.

All materials mentioned above have positive properties. Therefore, the builders are designed bodies, combined parts from different materials. Thus, when used, you can bypass disadvantages, but to use exceptionally positive qualities.

The Mercedes-Benz CL body is an example of a hybrid design, since such materials, steel, plastic and magnesium were used in the manufacture. The bottom of the luggage compartment and the engine compartment frame, and some separate framework elements were made. Aluminum made a number of outdoor panels and framework parts. Magnesium carcasses made of doors. The plastic is made of the trunk lid and the front wings. This design of the body is still possible, in which the framework will be made of aluminum and steel, and the outer panels are made of plastic and / or aluminum.

the weight of the body is reduced, while maintaining rigidity and strength,

the advantages of each of the materials are used as possible.

the need for special technology connection technologies,

complex disposal of the body, as it is necessary to pre-disassemble the body to the elements.

Aluminum.

Aluminum alloys for the manufacture of automotive body began to use relatively recently, although they were applied for the first time in the past century, in the 30s.

Use aluminum in the manufacture of the entire body or its individual parts of the hood, frame, doors, roof of the trunk.

The initial stage of the manufacture of aluminum body is similar to the manufacture of steel body. Details first stamped from aluminum sheet, then collected in a whole design. Welding is used in argon medium, connections on rivets and / or using special glue, laser welding. Also to the steel frame, which is made of pipes of different sections, the body panels are attached.

the ability to make parts of any form

the body is easier than steel, while the strength is equal,

ease of processing, recycling is not difficult,

corrosion resistance (except electrochemical), as well as low price of technological processes.

low maintainability,

the need for expensive methods of connecting parts,

the need for special equipment

significantly more than steel, since energy consumption is much higher

Thermoplastics.

This is a type of plastic material, which, with a temperature increase, goes into a liquid state and is done fluid. This material is used in the manufacture of bumpers, the parts of the interior cover.

easier steel

when processing minimum costs,

low cost of preparation and production in comparison with aluminum and steel bodies (not needed stamping parts, welding production, electroplating and painting)

the need for large and expensive molding machines,

in case of damage to the complexity in repair, in some cases the only output is to replace the part.

Fiberglass.

Under the name fiberglass refers to any fibrous filler, which is impregnated with polymer thermosactive resins. Carbon, fiberglass, kevlar, and fibers of plant origin are considered the most famous fillers.

Carbon, fiberglass from a group of plastics, which are a network of intertwined carbon fibers (moreover, weave occurs at different specific angles), which are impregnated with special resins.

Kevlar is a synthetic polyamide fiber, distinguished by a small weight, high-temperature resistant, non-combustible, for strength to break exceeds steel several times.

The technology of manufacturing body parts is as follows: The filler layers are fitted into special matrices, which is impregnated with a synthetic resin, then leave for its polymerization for a certain time.

There are several ways to manufacture bodyworks: monocletes (one piece one detail), an outdoor plastic panel installed on an aluminum or steel frame, as well as the power elements integrated into its structure without interruptions.

with high strength small weight,

the surface of the details has good decorative qualities (this will allow to abandon painting),

easy in the manufacture of details having a complex shape

large sizes of body parts.

high cost of fillers,

high demand for the accuracy of forms and clean,

the manufacture time of parts is quite long,

when damaged, the complexity is repaired.

No one is doubted that the car carrier of the car body is the main and most complex in production (and therefore in the price) to the detail of the modern vehicle. About him and will be discussed in this article.

From the history.

Of course, in Era Telug and Karet (the beginning of the history of the Body), he saved people from changeable weather, and served the consumer goods. With the emergence of the automotive industry under the external bodies of the body "disguised" the devices and nodes. For a long time, the body patiently worked only the roof that protects cargo, passengers, and devices. For the first time, in half a century of the 20th century, events for removing the carrier function from the frame started, and the translation of this component on the body. After the development of a few years, the body became the "carrier". In other words, in addition to personal "congenital" functions, the body began to play the role of a frame of support for devices, suspension, etc.

In order to achieve suitable stability, stiffness torsion and bending, the body parts were introduced into the body system: spars and crossbars, they strengthen the roof with its racks, doors, and so on. The Domestic Victory, the creation of which started in 1945, became a source of frameless serial vehicles. Of course, at the very beginning of the production of carrier bodies in the fortress were inferior to frame systems.

For this period, the situation changed towards the first. In any case, the difference is very insignificant. In the open-top machines, the lack of stiffness was reimbursed by the reinforcement of the car. In separate structures, the rigging was reached by connecting the front and rear side meters, more resistant to shock structures.

A little about definitions.

Body geometry A strictly defined body system arrangement of front and rear suspension, box, doors, winds and lumen devices.

The change (accident, modernization) of the body geometry leads to changes in motion, uneven wear of rubber and worsens the safety of passengers (increasing the possibility of driving, smashing doors on the go and so on).

Zones of deformation Defined constructive features of the body of space with reduced rigidity, specially created to absorb the energy of the impact. The deformation zones are provided for saving the integrity of the automotive salon and the health of passengers.

Contact welding Electric welding method, where electrodes are summed up to the areas of the welded parts, and high power current is carried out. In the heating position, the alloy of elements melts, forming a homogeneous connection. Welding places are continuous and point. The second way is so called "spot welding" (the connection is made at a distance of about 5 cm from the adjacent point).

Welding laser Connection of elements using a focused laser beam. The temperature in the place of the junction is just huge, but the distance of smelting from the edge is very slightly. From here there is a huge plus of this method, a practically invisible place of welding. So, there is no need for welding welding processing.

Power frame Cooked in the overall design of the bottom, racks, roof with frames of the windows, spars, amplifier beams and other power components that form the overall "cocoon" in which the passenger car lounge is located.

Body bodyguard.

In the modern high-speed world, the body of the car body began to perform a new task of the second level of passenger protection. On the first - belts, airbags, etc. For this car body broke into zones that have different degrees of rigidity. The front and rear produced more "pillars" successfully absorbing the power of the blow, and the salon body is more hard zone to eliminate the occurrence of traumatic situations and pressing the units in the body. Energy absorption is maintained using the crumpled "in the accordion" of some power structures that can bring damage to the health of passengers.

An unconventional solution was made in passive protection and increasing the body rigidity of the Mercedes Class A. designers in order for the engine that is under a short hood, when an accident could not cause damage to passengers, the bottom itself was designed by the double-sided designers formed a kind of "sandwich" with a void interval. Of course, with such an assembly, placed in fact at the bottom of the engine, in the case of a frontal impact, it is pressed during this gap, thereby protecting passengers of the cabin from damage. Also, it is worth noting that the battery, benzobac, as well as other aggregates and vehicles of the car are freely accumulated in this gap.

What and how the carrier bodies make.

In the manufacture of bodyworks, leaf iron, having a different set of parameters. For example, in places where power loads are increased, 2.5 mm sheet metal is used, and for the elements of the "plumage" of the hood, wings, doors, trunk 0.8-1.0 mm.

All items, of which the body will later appear, are connected using several types of electric welding. By the way, some companies use unusual methods for connecting body elements, for example, laser welding is used, or riveted with rivets in combination with very durable glue. In the range of materials for the manufacture of bearing bodies, the choice is not great.

Until this time, the serial vehicles were used exclusively sheet iron and, occasionally, aluminum. In the 80s in order to protect the body from rust, began to use galvanized iron first period with a single-layer zinc coating, later began to cover on both sides. As a result, the guarantees from end-to-end rust on the body increased from 6 to 10 years, somewhere even up to 12!

Most bodies for many causes are made of sheet steel. The most important of these reasons are:

• high strength;
• deformability (ability to draw);
• weldability (as well as suitability for opica);
• stainability;
• sufficient service life with proper anti-review processing;
• satisfactory cost.

In general, the following are applied Leaf Steel.:

• tonalist, cold-rolled calm steel brand RRST 1405 according to DIN 1623 (standard for quality), DIN 1541 (standard per dimensions) with a strength limit of 270-350 MPa, a relative elongation of more than 36%, with a matte, clean surface, thickness of 0.6-0.9 MM (supplied with a thickness interval of 0.1 mm), is used for species (interviewed) outer panels (roof, hood, doors, sidewalls, etc.);
• the same varieties of steel, which are indicated above, sometimes the thin boiling steel of the UST 1203 or UST 1303, that is, the worst quality, with the strength limit of 270-410 MPa, the relative elongation of 28-32%, the same thickness, which is indicated above, Used for non-dust (painted), outdoor panels, as well as floor parts (internal framework, amplifiers, floor panels, crossbars, etc.);
• hot-rolled steel tape for DIN 1624 (standard for quality), DIN 1606 (standard per dimensions) of the ST 4 brand with a strength limit of 280-380 MPa, the relative elongation of more than 38%, thickness of 1.5-2.5 mm and more, is used for Details located at the bottom of the body (amplifiers, supports, flanges, etc.), especially large thickness.

The design and technology of manufacturing parts should be focused on the maximum width of the supplied sheet steel (currently 2000 mm). For details operating in Copposional aggressive cpeed, it is necessary to use galvanized sheet steel, given that in the manufacture of parts such steel does not allow large devices (bending, a small exhaust). In special cases, it is possible to use aluminated sheet steel. Both surfaces of steel sheets can be subjected to special processing.

Light metals

Until today continues discussions about the feasibility of the use of light metals in bodyworkingSince using them, you can significantly reduce the weight of the structure. No matter how interesting is the aluminum body of special (racing and sports) cars and buses, nevertheless, the likelihood of using an aluminum sheet for mass production of passenger cars is small for the following reasons:

• The cost of aluminum (as a material) is almost 3 times more than steel. The cost of making a sheet due to the best aluminum plasticity is slightly smaller, at the same time the weight of the sheet is less than 30%, since aluminum has less durability, and in this regard, it is necessary to apply a sheet of greater thickness. However, cars are not sold by weight, but an increase in the cost of materials is too noticeable, since the reduction of the cost of other elements due to a decrease in total weight, for example, brakes, tires, etc., is negligible, and the decrease in fuel consumption does not affect the sales price of the car. Therefore, cars with lots of aluminum parts are becoming much more expensive.
• Due to the lower strength of aluminum, most body parts, especially the framework elements, should have an enlarged thickness. Due to the smaller modulus of elasticity, the rigidity, caused by the body shape, as well as its service life is relatively small, therefore, the absorption of energy at shock is also not enough. All this is undesirable in terms of security.
• Pure aluminum alloys have sufficient corrosion resistance. However, not all parts and connecting elements of the body can be made of light metal, at least in places of aluminum and steel parts, there is an increased risk of corrosion. The latter can be reduced by applying anodized steel sheet, but in this case the costs increase dramatically.
• There are difficulties with welding and soldering, which become feasible only under certain conditions (protection against oxidation).

According to the reasons listed above, the use of light metal in passenger car bodies is limited to internal parts made from sheet, castings or deformable alloys, as well as moldings, possibly bumpers. It is annoying that the cost of aluminum on the world market constantly fluctuates. Ultimately, the mass of aluminum parts, including the part of the chassis, in European passenger cars is about 2.2% of the total mass.

Meanwhile, some models of mass production are equipped with an aluminum hood.

Plastics

Recently, increased interest causes the possibility of applying plastics in bodyworkingAlthough one-piece plastic body or even plastic bearing nodes are a matter of a distant future. However, there are many sentences on this topic. From 1953, Ji-Em from 1953 made in a rather large number of Chevrolet-Corvette with a body, stamped from a polyester material reinforced with fiberglass. The body had a carrier frame from steel pipes. A multilayer structure, experimentally made for an open plastic body reinforced with fiberglass, is definite interest. In the future, in a small amount it will be possible to make a light open body of thermoplastic for special cars.

The benefits of plastics are low weight, high strength and rigidity, good noise absorbing properties caused by high internal damping, easy assembly of nodes achieved due to the possibility of manufacturing large parts, high corrosion resistance.

This undoubted advantages of plastics oppose significant disadvantages, in particular, the high cost of materials and their manufacture, a large duration of the technological cycle, difficult installation and repair, low energy absorption.

Due to the possession of these disadvantages of plastics are not suitable for mass production bodies. Nevertheless, the high manufacturability of plastics, the possibility of making parts by casting or using vacuum hoods allow you to widely use plastics for both small and large stamped parts. When choosing plastics, they are mainly guided by the mechanical and thermal properties of materials. The structure of the most important types of plastics are used in body buildings:

1. Thermoreactive plastics (so-called reactoplasts) according to DIN 7708, DIN 16911, DIN 16912 are used for highly loaded parts (levers, knobs); If the plastic is reinforced with fiberglass, it is also used for large parts of special (sports) cars called fiberglass, for example, for hoods, lids of trunk, decorative lattices, wings, sidewall, etc.
2. Various thermoplastics (below are only some of the possible materials that are offered under various brand names). For example, acrylonitrile-butadienestyrol is used for parts obtained by vacuum hood, such as a radiator cladding, instrument panels; Acrylo glass - for transparent parts, windows, diffusers, lanterns; polyamide - for well-sleeping parts such as moving elements of locks, air ducts, etc.; polyvinyl chloride - for elastic and soft details, artificial leather, film coatings, hoses, seals, isolation; polyurethane- for high strength details; Foaming polyurethane - for overlays, insulation materials; Polyurethane with a solid surface area - for handles, armrests, cladding, instrument panels, deformable facing front part, etc.
3. Elastomers (ethylene-propile rubber) with a monolithic shell are used, for example, for seals that are resistant to weather conditions and aging (doors, windows).

This list can only be considered as indicative. The industry producing polymers is able to offer or develop materials suitable for certain application conditions. Plastics have the following advantages:

• small costs for the manufacture of parts and low weight;
• satisfactory stability of specified sizes;
• simple processing and compound technology (gluing);
• the possibility of obtaining the surface of various colors and embossing (brilliant and matte metallization);
• high resistance to weather conditions and corrosion.

Due to the wide opportunities for the use of plastics, there is no surprise that the proportion of plastic parts (by weight) in the body is constantly increasing and at present, European cars are about 7.8% of the total weight. Plastics open great opportunities to reduce body weight.