Automobile production refers to the industrial production of automobiles in the automobile industry . Production takes place in the factories of the automobile manufacturers . The manufacture of an automobile requires a great deal of technical resources and employees.
Depending on the type of vehicle manufactured, the required number of pieces and the location of the factory, the manufacturing process has a different degree of automation . Some vehicles manufactured in small numbers are completely handcrafted. Large volumes of work are carried out manually even in low-wage countries . However, a large proportion of automation is typical of automobile production . For example, the use of industrial robots is highest in the automotive industry, with over 1,000 robots for every 10,000 workers in Japan or Germany.
Most of the time, cars are made in line today. The unfinished vehicle goes through numerous stations at which a few work steps are carried out automatically or by workers, which further complete the car (see also assembly line production ). As far as possible, automobile manufacturers only try to build vehicles according to customer orders and are striving for the principle of mass customization . For this, the production process is organized in such a way that as many vehicle variants as possible can be manufactured without interruption in a production facility or on an assembly line. If this is not possible or is only possible with difficulty, certain activities are no longer carried out on the final assembly line, but are relocated to pre-assembly, to the supplier or to logistics centers.
The automobile manufacturers manufacture the vehicles, assemblies and parts in numerous production plants that form an international production network. In order to ensure the quality of vehicles worldwide and to achieve efficient and cost-effective production, most automobile manufacturers have now described the principles and standards of their production organization, the production processes as well as the manufacturing processes and production methods in a production system . Due to the success of Toyota, they are more or less based on the Toyota Production System (TPS), which was the first to develop and introduce such a production system. In Germany, Adam Opel AG, as a subsidiary of General Motors, first introduced its own production system. This was followed by Mercedes, Porsche and MAN at the turn of the millennium, followed by AUDI and VW. Even large suppliers in the automotive sector, such as Bosch and Hella, have now introduced their own production systems, which in principle do not differ from one another.
Before the production of a new type of vehicle, there is its development, in which very specific planning and development phases (see below) are run through. The various phases and steps in the product development process sometimes run in parallel in order to shorten the development time (see also simultaneous engineering ). Not all development scopes and activities have to be carried out by the automobile manufacturer itself. Rather, certain development activities are taken over by special development companies and the supplier companies themselves.
First of all, based on market analyzes, it is determined which type of vehicle is actually to be built, what quantities are required and what general properties the product should have. The future price of the car is also determined here and influences the next development steps (see also the production program ). This includes, in particular, the definition of which production processes and according to which production principles and standards the vehicle, the units and components are to be built at which production locations. This also includes the definition of the vertical range of manufacture .
Design phase, (pre) development
The design of the vehicle is derived from the specifications of strategic planning. This is where the future appearance of the vehicle is essentially determined ( cubing model ). Here you can already decide how well the car will sell later. Based on this definition, the design and parameters of the production systems and processes are checked and may have to be adjusted.
In this step, the entire technical design of the car is determined. This is where all the individual parts of the vehicle are designed and how they are assembled in order to obtain an automobile that meets the design specifications. The following points must be taken into account during construction:
- Legal requirements: For different markets such as the USA, Europe and RdW (rest of the world) a wide variety of legal requirements must be observed in order to be allowed to sell the vehicle there. These regulations relate to a. on the occupants (headroom, viewing angle ...), the pedestrians (no protruding parts; Daimler and others have special permits for historical reasons) and the environment (emissions such as noises, smells, exhaust gases, recycling ...).
- Costs: The design of the individual components and the overall construction significantly influences the subsequent production costs of the vehicle.
- Properties of the end product: The finished vehicle should have certain properties ( crash safety , comfort, etc.). The construction must be carried out accordingly. Simulation is often used for checking . The positioning in relation to the competition vehicles with regard to the most varied dimensions (length, height, width, headroom, loading volume ...) is also becoming increasingly important. For this purpose, the corresponding dimensions and dimensions of the competitors are analyzed in the preliminary development and the own development is designed accordingly.
- Quality: The later quality of the car results from its construction. A higher quality usually means higher costs. A compromise must be found here in accordance with the specifications from the strategic planning.
- Manufacturability: The construction not only has to take place in such a way that the car receives the desired properties, but also the individual components have to be manufactured (as cheaply as possible), assembled and exchanged for any repairs during the product life cycle. Also, in the manufacturing (. Eg drawing simulation in sheet metal) and assembly (assembly planning) comes simulation used. The actual construction of the car and the associated tools takes place at large automobile manufacturers in several loops, using CA techniques (CA = Computer Aided). Usually a virtual prototype of the car is built first, i. H. the entire vehicle is designed and displayed as a virtual model on the computer. This is usually followed by several loops in which ready-to-drive prototypes are built on defined dates. These vehicles have to undergo various tests as Erlkönig in the laboratories, on the test sites of the automobile manufacturers, on rented racetracks and sometimes in public . The assembly of the individual components of the vehicle is also tested here. The results from all these tests flow into the next loop in the construction. In parallel with the improvement and optimization of the components for the car, the associated tools are also designed.
Factory planning and production planning
The production buildings and production facilities must be planned in parallel with the construction of the vehicle. This involves the planning of all relevant production areas in which the (new) vehicle can be built inexpensively and with high quality. Vehicle production often has to be integrated into existing factories, which is why the existing resources are used (in whole or in part) . In this case it must be taken into account that the existing production remains functional as continuously as possible during the renovation work. Supplied parts must also be checked in order to assess their interaction with parts from other suppliers in terms of optics, haptics, gap dimensions, and ease of assembly, for example with the master jig .
Production trial and pre-series
After production planning has been completed, the production processes, systems and machines must be tested and run in before production can actually start. In addition, the first vehicles are still being produced as a pre-series to ensure the quality of the products. Only then will the actual series production of the vehicles begin; in this context one speaks of the start of production .
Production steps and production structure
When the automobile is completed, the production areas described below are usually passed through. In modern factories, it is known from the outset for which end customer each vehicle is being manufactured. In other words, exactly the components that a specific customer ordered are installed during production. Due to the large number of variants, special methods and processes of production planning and control have been developed in the automotive industry, which are particularly suitable for the flow production that is widespread in automotive production. The production structure in automotive engineering can also be mapped as a closed interval algebra. The production areas lying one behind the other form a sequential material flow route, with the individual routes (intervals) each being separated from one another by a clear detection point, metering point (logistics) . Based on this structure, the entire production process can be planned and controlled using appropriate control loops. The production progress of the vehicles can be monitored at the recording points, and suitable control measures can be initiated in the event of deviations. The vehicle in production is transported between the individual production areas and stations using conveyor technology . A typical automobile production extends over several halls and sometimes over several floors. The delivery areas and areas for component production are usually located on the ground floor. Because of the heavy machinery and dynamic loads, the press shop and foundry are usually set up at ground level. The vehicle is continually being completed in the main production line (final assembly line). The final assembly line is either supplied with parts from the floor below or with assemblies and modules from the pre-assemblies that run towards the final assembly line and are linked to it for control purposes. The vehicles are often transported between the body shop, the body store and the final assembly line on a higher-lying conveyor level, in which the vehicles are transported between areas further apart via conveyor chains and conveyor hangers.
This is where parts are manufactured using a casting process that are built into the vehicle (e.g. engine block ). Engine blocks in particular are manufactured in stand-alone plants and often at other locations; many automobile manufacturers do not even pour themselves, but buy from suppliers. The cast parts for turbochargers are also mostly bought in.
The sheet metal parts from which the body is later assembled are manufactured in the press shop . The sheet metal is supplied in the form of large rolls ("coils"). These are cut into suitable pieces, which are then shaped into the desired shape in large presses . This takes place in several operations (OP). An "operating line" can have seven consecutive operating theaters that bring the sheet metal into the desired shape.
Shell construction / body construction
In this area, the sheet metal parts from the press shop are joined together to form the body shell using spot welding and gluing techniques.
The body shell is first protected against corrosion here . For this purpose, one or more immersion baths are often passed through. Depending on the process, there are one or two protective layers that are applied during the painting process. In preparation for the decorative varnish , the body is protected from corrosion by cathodic dip painting (KTL) . Then a so-called filler is applied, which enables the topcoat to be applied evenly. Then the top coat is applied, which gives the vehicle its desired color. It is sealed with a clear varnish.
The chassis includes all parts and assemblies such as axles, drive shafts, shock absorbers, struts, brakes, etc. These parts consist mainly of metal and are mainly mechanically processed (turning, milling, grinding, ...). Many of the chassis components are purchased from suppliers who specialize in making these parts.
Interior equipment (interior)
This production area includes all parts and assemblies that are built into the interior of the vehicle, such as door and side panels, interior mirrors, headliners, mats, compartments, shelves and covers. This also includes the numerous operating and decorative elements such as switches, rotary knobs, inlays, etc.
Exterior equipment (exterior)
This production area includes all parts and assemblies that are visible on the outside of the vehicle such as bumpers, spoilers, exterior mirrors, door sills, trim strips, roof racks, etc.
The gearboxes required for the vehicles are manufactured in gearbox manufacturing. In the gearbox assembly, the different gear axles and gears are built into the gearbox according to the type and number of gears. Approval takes place after a technical examination.
The different engines for the vehicles are manufactured in engine construction. Essential components of an internal combustion engine are the engine block, the cylinder head, the pistons, connecting rods, the crankshaft and the camshaft. These are put together to form the core motor and then completed step by step in the assembly process to form an operational motor. At the end there is a technical check and approval.
Final vehicle assembly
In this area, the painted body is supplemented with all missing parts. For this purpose, the doors and sometimes also the tailgate are dismantled and completed and equipped in separate pre-assembly areas parallel to the vehicle assembly. At the beginning, the electrical wiring harnesses are laid because this is no longer possible later, after installing the other parts and the cladding. This is followed by the assembly of the interior (carpets, interior trim, headliner, cockpit, seats, etc.) and other attachments (windshield wipers, lights, wheels, trailer coupling). The merging of the body with the engine or a complete drive train is referred to as "marriage" in automobile production. Finally, the previously dismantled doors and flaps are reattached to the automobile on its own wheels and the operating materials (fuel / oils) are added. Finally, the electrical functions and various settings on the vehicle are checked. Today, this also includes the “ flashing ” of control units that receive a lot of information about the vehicle that is necessary for their functions. These are e.g. B. Installation information for a central locking system whose control unit is configured, whether the vehicle is a 3 or 5 door and whether the tailgate has an automatic locking device, but also activation options for additional equipment or special interfaces for taxis or police vehicles, as well as a vehicle key for identification.
As a rule, a vehicle manufacturer now calculates around 15 to 20 hours to completely assemble a Golf class vehicle from all its individual parts, depending on the complexity of the subassemblies supplied. The record holder here is the small car Smart , which is completely assembled in about 4 hours. This is due to the large number of prefabricated and pre-assembled modules that the suppliers provide on the assembly line and that the vehicle manufacturer only has to assemble.
Finish and quality control
Only after complete assembly can the functionality of the vehicle be ensured through various adjustment work (e.g. adjusting the track) and checks that the vehicle has been produced without errors and meets all requirements. Due to the increasing use of control units in vehicles, extensive electronic function tests are required today. These are carried out on test and run-in stands or also on test drives that check the operation of the individual and the interaction of all control units and their connected components. For the check, special equipment-specific test programs are required, some of which require the use of different data loggers and vehicle diagnostic systems. Finally, real test drives are carried out, whereby special road profiles (vibration track, ...) and weather conditions (rain, ...) are simulated. After the checks and adjustments, a product audit is carried out on some vehicles by quality assurance , for which the Association of the Automotive Industry has made appropriate recommendations as part of quality management .
Special car construction
In the construction of special vehicles, fixtures are made which cannot be carried out (profitably) in series production. It is z. B. special equipment for companies or special professional groups (taxis, ambulances), or custom-made products for customers with special requests. The German manufacturers have even founded their own subsidiaries for this purpose, which take care of the individualization of the vehicles for these special customer groups (see Mercedes-AMG , quattro GmbH , Volkswagen R , BMW M ).
After successfully completing the test, the vehicle is usually transferred from the final assembly plant to the delivering dealers worldwide by means of a car transporter (truck, train, ship) and handed over to the customer there. For some plants, some manufacturers offer customers the opportunity to collect their vehicle directly from the final assembly plant (e.g. Autostadt ).
Automobile production is controlled on three levels.
- 1. The execution level , on which the individual systems and machines are controlled and the real operating data is recorded (see also BDE ). Above all play PLCs a major role.
- 2. The control level , which is responsible for the commissioning and coordination of the individual systems and production sections of the 1st level. All individual vehicles are managed here, their passage through the production systems is monitored and the production results are recorded. Here it is controlled, for example, that the vehicle doors find their way back to their vehicle after removal. This level has interfaces to warehousing, the logistics center and directly to the suppliers for deliveries in accordance with just-in-time production . The production control center , the manufacturing execution system and / or the workshop control are also located on this level .
- 3. The program level , which is responsible for creating the production program and commissioning the various production areas on the 2nd level. The production program contains the individual vehicle orders from customers and dealers with detailed equipment information for the vehicle and the completion date. This information is passed on to the individual production areas and their feedback is compared and taken into account in the next program run. This level is integrated into the PPS system and has interfaces to the software systems of the other company areas such as finance, procurement and sales. This level is closely linked to the MRP I , MRP II and the ERP systems.
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