Somewhere along the way, every Volkswagen enthusiast should try to visit Wolfsburg, Germany, the headquarters of Volkswagen AG. There is little that can prepare you for the complete immersion into a world of Volkswagens when you arrive. From the time you enter the city of Wolfsburg there is virtually no car to be seen that isn't a member of the Volkswagen brand family - Volkswagens are everywhere. Fans of the marque may feel like they have died and gone to heaven here. From the rare air-cooled split window bus to modified Golf IV models with flared fenders to the New Beetle RSI, there isn't anything we didn't see on the streets and in the employee parking lots.
The process all starts with raw materials. Carefully considered suppliers provide the best sheet metal possible and deliveries arrive 24 hours a day. Much of all the materials and parts in the factories are delivered on a "just in time" basis so there is very little in the way of storage facilities and raw materials or parts stacked up. The above amount of sheet metal will only last a few hours and is constantly being replenished through the 24 hour work day.
Volkswagens have characteristic flowing lines, making exacting demands on the dimensional precision of the body panels. The tool and jig constructions division provides the necessary basis for this. Specialists in Wolfsburg can turn even the most complex shapes into reality with the "tools" they construct. A "tool" is a form used to create a pattern (a fender for instance) out of raw sheet metal. Some of these tools weigh more than 50 tons and have to endure very exacting and long lifecycles of constant pounding in the presses.
Sheet metal is "alive" say the experts, meaning that the shape of the pressed part after the deep-drawing process is not absolutely identical with that of the die. The metal always reverts a little after shaping. From years of experience, the specialist toolmakers know how various factors influence the dimensional precision of pressed parts. Knowledge of the interaction between nature and materials, sheet thickness and the extent of deformation are all parts of the foundation for high quality in body construction.
Good tool and jig construction is key to determining how wide and how accurate the panel gaps are and how precisely the sheetmetal is formed. The Wolfsburg press shop processes some 1,500 tons of sheet metal a day. All the sheet stock is pretreated in various anti-corrosion processes. The material used for the outer bodyshell skin is a light matte grey, having been galvanized by electrolysis for an especially fine surface. By comparison, a bright metallic surface indicates that it has been treated in the melting bath - also known as hot-dip galvanization. This is a robust material for the floor pan and internal parts.
Unrolled and stamped into blanks, the sheet metal is transported to the press lines. Here large capacity vacuum presses force up to 6000 tons of pressure to achieve the desired shape. Deep-drawing is divided into several stages. The entire process runs simultaneously and at low noise within one machine. The process is monitored by cameras and transmitted to a central location. Of particular importance are the the dimensionally-critical parts, for example the floor pan for manufacture of the platform; these parts are made only in Wolfsburg. They form the basis of every vehicle body, thus ensuring high precision and quality at all plants they are supplied to.
(Above) One of two Schuler presses in operation at Wolfsburg. These presses are state-of-the-art and a significant investment on the part of any manufacturer. Don't let the photo deceive you, this press is over 3-stories tall and almost a football field in total length. It also goes 1 story under ground and requires nearly 40 feet of solid concrete as a base to protect against vibrations and sinking.
(Below) From ground level here you see closeups of the actual "tools" (grey device on top of the blue slider trays). Each of these tools and slider trays is over 25 feet in length and about 8-9 feet in height. When a tool needs to be changed it takes only 10 minutes. The orange doors are opened on both sides of the press and the current tool is slid out one side while the new one is slid in to take its place right behind it. This means that tool changes from Golf IV body stampings to Golf V body stampings can occur in as little as 10 minutes. Prior to the Golf IV, these Schuler presses weren't in existence at Wolfsburg and tool changes took many hours to complete. These high-end presses were just some of the many huge investments that took place during the 1990's to upgrade the factory.
(Below) This photo (taken from above) shows a tool used to produce the new Polo left-hand side outer sheet metal from the A-pillar back. This includes the door openings and door sills (4-door model), rear fender flares and third window cutout - all stamped as one unit. The sheet metal is fed into the Schuler press, pressed into a tool like the one below, extracted and then trimmed and finished to take any rough edges out of the piece all in the machine - all at a rate of more than 450,000 formed sheet-metal parts per day. From there they are stacked vertically on carts and taken over to the welding area where they will be attached to the floor plan and roof supports.
The bodies for the Golf and Bora (Jetta here in North America) are produced at the Wolfsburg factory on three identical production lines. The operation frequency of just under one minute determines the rhythm of the work and the transportation phases of the three lines, which together produce over 200 units per hour. This three-line system called segmentation, allows greater variability. Golf and Bora bodies can be produced in direct sequence without any loss of time. Welding robots and picking tools are designed accordingly as multifunctional units.
Another advantage of segmentation is that it provides for continuity of the processes in the plant. If one line is undergoing maintenance or adjustment, production can continue unabated on the other two. Market fluctuations can also be balanced out in this way. The company can react flexibly to dealers requirements. Popular model versions are manufactured in greater numbers and production of those less favored can be throttled back.
Some 800 million Deutschmarks ($400 million dollars) went into converting production to the Golf IV body shop. The automation level went up to 96 percent, highlighting a trouble-free and exacting process with little to no reliability issues. The same applies to the fully-automated production islands, where robots assemble the pressed parts into individual assemblies. These modules are integrated into the assembly lines through various processes. More than 4,000 spot welds, laser weld seams and bonding and cold joining technology give each body its high rigidity and strength.
(Above) 96 percent of the body shop is automated, providing for extremely reliable and tight tolerances in both the construction of the floor plan and the sheet metal attached to it. The above orange robots are performing spot welds to a Golf. The area surrounded by the green curtain is where laser welding takes place.
(Above) One of the final stages of the body shop assembly before leaving for the paint facility is the manual installation of the doors. Machines are guided by hand into exact positions to ensure proper alignment. After this, front fenders, hood and trunk lid are attached and the car is sent across the plant property on a conveyor system to the paint facility.
Primarily intended as a protective coating, the paintwork is just as important in its visual appeal as well. It most be resistant to all forms of attack - UV radiation, heat, rain, snow, frost and even stone chips. Car and attention to detail therefore have top priority.
In the past this production stage was characterized by dirt, solvents and the emission of paint particulates. Today the Wolfsburg paintshop activity is defined by "clean-room" technology, low-solvent finishes and efficient scrubbing of the paint mist with a water circulation system as well as intense water purification and recirculation.
Degreasing, pre-treatment, washing and drying phases are the initial stages of treatment. Then follows the electrolytic dip-priming (photo below).
All metal joints are then sealed along their seams and folds, thermoplastic sound deadening materials are inserted for noise damping. In addition to the paint finish and galvanization, the underbody seal protects against possible subsequent damage from stone chips and corrosion. After the filler coat and the pigmented coat, a clear finish is applied as the final protective layer. This coat alone is what gives the required glossy finish you see in the showroom.
All finishing work is done by robots. The atomized paint is transferred in an electrostatic field to the body, with low losses in the process, and adheres to the metal. After the paint has been applied, an additional internal precaution against corrosion is taken using the hot wax cavity flooding process patented by Volkswagen. This protective measure is used on all models.
Years ago the Wolfsburg paintshop was one of the first in the German automobile industry to introduce low-solvent water-based products for the filler and pigmented coats as well. This has drastically reduced environmental pollution as a result.
(Above) Electrolytic dip-priming - a new Polo is lowered into the electrolytic dip-priming bath which uses negative charges to adhere paint to all portions of the car to ensure absolute coverage of all exposed metal.
(Above) Robotic sprayers move in fluid motions around the car, in this case applying a base color coat. Changes in color can occur in less than 5 minutes and eliminates the need to paint a batch of vehicles in a single color and then a second batch in a second color etc., etc. Vehicles can be painted individual colors one right after the next on the assembly line.
(Above) A silver Polo leaving the heat curing booth after having final color coat applied.
In final assembly, the painted bodies are completed in accordance with customer orders. In the case of the Golf, the individual engine, equipment and color options theoretically make over 3 million possible combinations. However, the more realistic and more frequent selection possibilities only number around 300,000. Without a maximum of product-oriented and process-oriented flexibility, however, such a variety would not be possible. Product-oriented flexibility is already evident in vehicle development. The front-end for example has been designed in such a way that it can accept various engines. Process-oriented flexibility on the other hand means that the machines needed for manufacture are multifunctional and can be adapted to changing models and equipment versions.
A Golf for example consists of 31 main modules and 54 submodules. Assembly consequently requires highly organized work processes and standardized interfaces. Thus dashboard and front end, the entire running gear with engine, gearbox and exhaust system are pre-assembled in parallel in sequence controlled production, tested and installed as complete modules. The painted doors are taken from the body and also completed on a separate line. While the doors are removed, the dash board, seats, carpet and full interior components can be installed. At a later point the doors are returned to the right vehicle by a conveyor system. This modular construction process accelerates production and makes it more economical.
The function and precise interaction of all assembled parts and modules are then tested. This also involves a test run on the dynamometer, a drive over a special jolting section to test for creaks and rattles and a waterproofing test in a sealed high-pressure spray cabin.
After this the work is done - the vehicle is taken to the train yard or to waiting delivery trucks for local dealers.
(Above) A dashboard is carefully inserted as one complete finished unit into a Bora with wiring harnesses and looms already pre-wired. The bar-code chart found under the hood tells workers exactly which components are to be installed on that particular car and trim level. Each car on the assembly line is custom ordered and built to specifications uniquely from the car after it. A left-hand drive U.S. spec model may be followed by a right-hand drive Japanese model, followed by a German-spec model. Parts arrive according to a "just-in-time" system with the exact specified parts for that particular vehicle at that particular station within minutes of when they are to be installed. It is an amazingly orchestrated sequence of events.
(Above) The headliner is installed in a Golf four-door.
(Above) The marriage - This is the point where the driveline components and engine are "married" to the body. The driveline and engine components come up from the lower level through the floor as a single unit and are inserted into the underside of the body shell in a completely automated process.
For most Volkswagens coming off the assembly line the first big trip takes the form of a rail journey. Every day 110 double-decker train cars carrying some 2,400 Golf, Golf Variant, Bora, Bora Variant and Lupo models leave the rail freight station at the Wolfsburg plant. Only a small share leaves in about 90 road car transporters, primarily for transportation to dealers in the region. It may be hard to credit, but almost all of these new vehicles have been produced to individual customer specifications (or in the case of North America, to VWoA specifications). Equipment, engine, color, seat covers and many other features are selected by the customer from the wide range of possibilities. So while colors and engine choices recur, in other respects combinations are selected which seldom come up more than once in a working day. It's worth bearing in mind that Volkswagen in fact builds individual personal cars en masse. The sales division runs 11,350 outlets throughout the world, with over 2,800 of them in Germany alone. These dealerships coordinate all customer wishes. To channel these orders correctly, the sales division in Wolfsburg operates a high-performance computer network system, which is also linked with the data processing system in production. In the factory, starting at the body-in-white stage, a small card with a bar-code incorporating the necessary data controls the vehicle's production in line with the customer's wishes. While customer ordering your Volkswagen is not yet a reality here in North America, it is possible for your dealer to look up allocations of current cars available and those still being produced to see if one matches what you are looking for.
If you ever have the chance to tour one of the Volkswagen factories, don't miss it. Tours of the factory in Wolfsburg, Germany are available as part of your admission to AutoStadt and are available seven days a week during normal business hours. Actually seeing the magnitude of what is involved in simply building a car is something you won't forget and will make you think differently about your Volkswagen from that day forward. The investments in technology, production methods, paint and more are all great signs that Volkswagen is committed to the future and striving to build the best cars ever to leave their factories.
(Above) Wheels are installed on a Bora. The wheel and tires arrive on the assembly line mounted and balanced and ready to be installed. Even more impressive are the conveyors that deliver the correct type of wheel and tire for that specific model exactly when it is needed for installation.
(Above) A Bora sedan leaves the test booth where the vehicle is placed on an in-floor dyno with a VAG tool hooked up and run through a series of tests to make sure all electrical systems and engine management systems are operating properly. Every car is put on the rollers and tested before leaving the factory.
(Above) Just a tiny view of the rail yard at Wolfsburg. These trains move more than 2,400 vehicles out of Wolfsburg every day.
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