Products and solutions, 2003-09-09, 02:00 AM
Lamborghini body sets new standards
ThyssenKrupp Drauz - specialist for innovative lightweight solutions
ThyssenKrupp Drauz is an automotive supplier specializing in auto body construction and has completed numerous projects concerned with the realization of lightweight body construction concepts, particularly for niche vehicles. The company is partner to Audi, among others, for production equipment, hydroforming and tools for the Audi A2 and A8.
ThyssenKrupp Drauz was included in the body project for the Lamborghini Gallardo with Audi in 2000. A team of toolmakers, production planners and plant builders worked closely with colleagues from Audi. The SE work was supported by a controller who calculated the effects of any major changes on the cost and investment budget.
Audi and Lamborghini`s requirements particularly concerned the realization of a production line for an aluminum-body niche vehicle meeting volume-production quality requirements. The production line was designed for two shifts with a cycle time of two hours and a total of 58 staff.
Picture: ThyssenKrupp Drauz produces the complete BIW for the Lamborghini Gallardo in Heibronn, Germany.
<small>Copyright: ThyssenKrupp Automotive</small>
The parts were delivered individually to Heilbronn. The assembly sequence evolves from the assembly of the subassemblies, starting with the floor assembly - frame, side section mounting, attaching the greenhouse and the subsequent assembly of the add-on parts, doors, hoods and fenders. This is followed by the finishing and the quality check. Once a day, a body is also measured in series production. In addition to the around 200 functional measurements, further measuring points for the geometry were systematically recorded and evaluated.
The chassis mounts are drilled by hand using guides. This meant that the usual CNC drilling and milling equipment could be completely eliminated from production. Nevertheless, the quality requirements were achieved in the defined areas.
The uncompromising design of the outer panels presented the ThyssenKrupp Drauz toolmakers with great challenges. Amongst others, the problem areas were finely tapering tornado lines, various surface transitions in one component, the flat contours of the tailgate and an almost vertically tipped C-pillar inner wall, as well as a complicated side wall with numerous exposed joints, e.g. air intake and doorway in combination. The side wall assembly alone had 2.20 m of MIG welded seams. Alternating current MIG welding apparatus was used in order to minimize heat input during MIG welding.
Picture: ThyssenKrupp Drauz employees are allocated a high degree of responsibility in production.
<small>Copyright: ThyssenKrupp Automotive</small>
All fixtures are of the same aluminum-adapted design used for the Audi A2 and A8.
Examples of aluminum-adapted design are:
- Components can expand and contract freely in the fixture in order to reduce thermal stresses.
- Use of copper in the fixture to ensure optimal heat dissipation.
- Exposed weld finishing reduced through the use of finishing adhesive.
Of the approx. 115 meters of the MIG welds, five meters are in the outer panel area.
Punch riveting, self-tapping screws and robot seam rollers were also used as joining methods in addition to MIG welding.
Screw connections were used particularly where metal panels lie adjacent to profiles in the structural area. For the first time ThyssenKrupp Drauz used the "Flow Drill Screw" system (FDS) which Audi has developed considerably further. This system enables the use of self-tapping screws without any pre-drilling and was integrated into a robot cell together with the impulse riveting process.
Picture: Lamborghini Gallardo.
ThyssenKrupp Drauz had particular success with the development of the impulse riveting technology. The rivet is no longer set into the aluminum with a C frame, but is shot in on one side by means of an impulse. This means that the apparatus is smaller and, at approx. 50kg in total, is considerably lighter than a traditional riveter. Critical areas such as tunnels can be riveted to the floor panel or the front end without any special measures. Large and more expensive riveters are eliminated, as well as the heavy-duty robots needed for this.
In the meantime ThyssenKrupp Drauz has developed machines for the 3 and 5 rivet using the impulse riveting process.
As joining times and costs are now similar to those of spot welding, additional growth areas will open up for composite aluminum - steel - plastic - magnesium constructions.
The production procedure is continuously improved through Kaizen measures and the further training of staff. Additionally, job rotation for staff encourages the motivation of every single employee. The focus is on the team and the people, whose vocational training and attitude to work are the success factor for realizing the quality requirements of volume production in the production of a niche vehicle.
ThyssenKrupp Automotive AG
Tel.: +49 / 234 / 919 - 60 12
Fax: +49 / 234 / 919 - 60 14