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Volkswagen relying on high-quality fixturing systems for Phaeton

In this top level Volkswagen automobile there is a lot of quality work from Zwickau involved. The body for the top class “Phaeton” model of Volkswagen is built in Zwickau/Mosel manufacturing plant and as far as measuring is concerned is closely looked at during the complete manufacturing process. Highly modern equipment is used for all QA checks, after which final assembly takes place in the glass factory in Dresden.
The measuring rooms in Zwickau reflect the high demands on quality that the company have set themselves. Just like the car itself, technical standards in manufacturing, production and measuring rooms are combined with visual aspects on a high level. For this reason quality and optics were decisive in the choice of measuring and checking fixtures.
Alufix modular fixturing system from Witte Bleckede corresponds to all requirements of the automobile builders with regard to flexibility and precision. Further, Zwickau has collected long-term experience with this system made of high-tensile aluminium. It was already used for other models such as Golf A4 and Passat B5 limousine. Today approx. 95% of fixtures in Zwickau come from Witte. The fact that other plants work with Alufix has proved to be advantageous. When the same parts are being produced in different plants repeatability of measuring results is achieved due to the use of similar fixtures. This includes i.e. fenders, which are manufactured in Brunswick and are measured not only there but also in special cases in Zwickau.
Several factors play a role when choosing a fixturing system - accuracy being the most important - quality planning engineers underlined and after that flexibility. Continuously shortening developing times mean enormous pressure because of tight deadlines. Whereas previously a new model was brought onto the market every four years, nowadays a maximum of two years are available. This means that fixation and clamping points of fixtures at the time of purchase are often not accurately defined and therefore model changes, which are integrated during prototype and zero series, must be incorporated into the measuring fixture during design These changes must be carried out short term on the spot. Fixture changes in the manufacturer´s plant mean unnecessary time loss. In order to adhere to the defined deadlines action they have to be carried out without delay.
Alufix components with a through grid are available in system sizes 16,25, 40 and 50. These dimensions correspond to the distances from centre bore to centre bore. Small grid sizes are ideal for holding small workpieces and large grid sizes are intended for big heavy parts. The Phaeton fixtures, on which for instance floor, sidepanels, doors,
fenders, rear walls etc. are held, comprise mostly of Alufix 50 components. The fixtures are positioned using centering pins on sandwich plates and transported on guiding equipment to measuring machines. As not only fixtures but also sandwich plates are manufactured in high-tensile aluminium, considerable weight savings are achieved compared to steel versions. This eases handling and relieves loading stations working in automatic measuring cycles Pallet stations comprise of several loading areas, which are alternately transported to the measuring system on a roller system, thereby allowing several workpieces to be prepared for measuring while the CMM is still working. This saves time and means the measuring machine is being put to optimum use.