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Opel AG: Manufacturing of the Astra New Astra manufacturing -State-of-The-Art Production Methods Intensive employee training
The start of Astra-production concludes the comprehensive restructuring of the home plant in Bochum and modernization of the facilities in Antwerp and Ellesmere Port. Opel has invested a total of around DM 2.6 billion in the four European plants.
Since well-qualified and highly-motivated employees are essential to the production process, Opel introduced a comprehensive training program for the workforce. Astra core-teams were formed in each plant and in February 1995 the program started with the assembly of several prototypes under near-production conditions at Ruesselsheim. The teams were able to gather first-hand knowledge of the new model, identify possible difficulties and cooperate with the engineers in developing improvements. Finally, selected employees from each plant were trained on a pilot assembly line in Ruesselsheim, which was similar in layout to the later production one. During this phase, standard work sheets were drawn up on which the exact sequence for each assembly stage, the time required and the necessary materials were documented. The new Astra was also used to introduce a new pre-production process at each plant. In the second half of 1997 an increasing number of new Astras entered the assembly line alongside the previous model. The objective was to test the new methods in genuine production conditions and to improve the process still further with the aid of experienced local employees. Opel invested around DM 15.2 million in the employee training program, the total number of training hours being 240,000. The Bochum plant shows how much effort Opel has put into ensuring high quality at the Astra plants. The company has installed a large, high-tech transfer press which not only replaces an entire line of presses but also combines precision and speed. It is used daily to shape Astra side panels, doors or roofs from 420 tons of zinc-coated (galvanized) steel. Production tolerances lie within 1/10th of a millimeter. Particular attention was paid to reducing turnaround times, cutting down cost-intensive material buffers and lowering storage and transport costs. For example, the radiator module, the fuel/brake systems and the entire front suspension with pre-assembled steering, as well as the door, cockpit and engine modules, are built up at the assembly-line installation point, working at the same frequency. Individual body-in-white parts such as side panels, doors or hoods are assembled in production cells which can react more flexibly to the various model versions. The plant designers also improved ergonomics on the assembly line by adopting new conveyors. This has resulted in the complete elimination of any overhead work, since the body-in-white conveyor system is automatically adjusted to the ideal height for each assembly stage. Such "user-friendly" methods can also be seen in the joining of the body and chassis (the "marriage"). With the new Astra, Opel has for the first time fully automated this time-consuming and, for the employees, strenuous task. All the chassis components - front suspension with subframe, steering, engine/gearbox unit and radiator, along with the rear axle and exhaust system, can be installed on an assembly-rig conveyor belt at comfortable working-height. The assembly rigs are then synchronized with the lowered body, joined and bolted together. Prior to this a similar principle is used to attach the complete fuel tank, brake and fuel lines to the body. Another example which shows how much the production processes in the Astra plants are geared to satisfying quality criteria is the further improvement in anti-corrosion protection for the fully galvanized body. In an extended cataphoretic process, the finished body-in-white is dipped into a bath in which an additional protective coating to safeguard against corrosion is added by an electrolytic process. Cavities are then sealed after the body leaves the paintshop. All finished cars have to undergo a thorough final inspection after leaving the assembly line. Firstly, front wheel alignment is measured at a laser-assisted test station and precisely adjusted. Every car then has to pass a precise pre-determined Dynamic Vehicle Test (DVT) on a roller dynamometer that simulates everyday driving conditions. The final inspection includes a rigorous braking test, extensive engine diagnosis and checking of all important electronic components such as ABS, traction control or cruise control, via ECOS (Electronic Check Out System). An acoustic audit, speedometer calibration and an engine and rear axle noise-level measurement are also carried out. Another safeguard of Astra production quality is the Opel Production System which operates according to the zero-errors principle. It is based on the concept that employees in every production area shall refuse to accept any parts or cars which contain errors, or release them for transfer to subsequent production sectors. Special "quality gates" have therefore been installed in the body shop, paint shop, trim shop, final assembly and dispatch areas, where the standard of work in the various assembly stages is thoroughly scrutinized again. Automatic checks also ensure that a high degree of process reliability is attained. For example, several electronic control systems monitor the quality of screw-connections. Audible or visual signals warn the employees of any errors and, if necessary, the assembly line can even be halted until the error has been rectified. In Close-Up: Integration of Suppliers Parts suppliers were heavily integrated in the new Astra's development, with many components already undergoing intensive evaluation during the pilot phase. For example, Quality Control inspectors took a particularly long, hard look at the exact fit of all interior parts, testing their conformity in an exact replica of the interior - a "cubing buck". This process played a decisive role in the coordination of all body components. An entire specimen body was created especially for this purpose, manufactured according to precise CAD data with no production tolerances. On this "Astra template" the inspectors were able to check the exact fits of various metal panels and plastic components - both individually and by comparing them with one another - well ahead of the production start-up.
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