Aluminium Cars, the Market and Production Volumes

The target market for an all aluminium car would be very much dictated by company policy and business strategy of the automobile manufacturer. For example when Audi produced the A8, which was a relatively expensive, lower volume, luxury automobile, the company strategy was to demonstrate that the material aluminium is fundamentally suitable for vehicle body manufacture and to illustrate the ease with which body repairs on aluminium vehicles could be carried out. Daily volumes for the A8 ran up to about 80 vehicles a day and because the A8 was at the higher priced end of the market it was felt that the increased costs associated with the initial excursion into using aluminium structures could be more easily absorbed.

For the A2 on the other hand, which was a smaller family type hatchback, the emphasis was on production technology and on validating the process of high volume production.

Daily production for the A2 ran at around 300 vehicles a day and the production processes have a degree of automation similar to that utilised in the production of steel bodied cars which is around 85% and is markedly different to the 25% automation level initially employed on the production of the A8, although steps were taken to increase this level of automation to a similar level to the A2.

In order to achieve the production volumes required at acceptable costs and quality levels, Audi entered into agreements with strategic business partners, identified through their work on the A8. This was with a view to improving the material properties of the aluminium alloys they used i.e. optimising the materials for specific functions to help overcome shortfalls identified in their previous exposure to production of aluminium vehicles such as removing the need to perform straightening operations during the production process.

One of these relationships was with Alcan, one of the main producers of aluminium. This has resulted in Alcan becoming one of the biggest suppliers of aluminium parts for the A2, not only supplying finished components such as extrusions and castings but also developing and supplying the specialist materials previously discussed.

Audi also sought to improve the production processes they had identified as most appropriate for aluminium car production again by entering into strategic business partnerships with the suppliers of specialist welding, bonding and mechanical fixing equipment.

Besides the business partnerships they entered into, Audi sought to develop core skills in the production of aluminium cars, in their case this centred around the ability to produce very high quality, close tolerance outer skin components on a volume basis.

Having invested somewhere in the region of 300 million Euros in plant and capital equipment Audi have committed to the further and increasing use of aluminium in their car designs not just for the models mentioned but across the whole range of vehicles produced by Audi. This effectively means that the use of aluminium will increase in all market sectors that Audi supply to.

Ref. Dr. Wolfgang Ruch (2001)

Audi have demonstrated that Aluminium cars are a viable alternative to steel cars in both medium and high volume production. For the high volume option where margins would be tighter they needed to achieve high levels of innovation both in the development of the car and of the supporting manufacturing processes in order to make this a viable enterprise. Without access to the company figures on sales and profit margins the assumption that they have managed to meet a market need and have done that cost effectively has to be made and is supported by the evidence of further investment in capital equipment required to raise the automation level for the A8 model.

A clear part of Audi’s approach was also to answer the make or buy questions as part of their business strategy making good use of external expertise whilst developing their own core skills in areas they felt they could excel, getting this balance right is also crucial to success in terms of where and how capital is invested in order to keep an edge over competitors and to be able to compete in the market place.

Tha last Audi A2 left the productions line at Neckarsulm in August 2005 but set the standard for aluminium cars manufactured on a high volume production basis.

Aluminium Cars - Paint Finishing Processes

Aluminium Car Finishes

Because of the nature of aluminium and in order to achieve necessary stiffness requirements in the finished condition, there has been a need to develop new aluminium alloys that can be heat treated after assembly. This particularly applies to sheet material that is typically pressed in its softer T4 condition with the intention of heat treating it as it passes through a paint shop.
Ref. Whiteley, F (1994)

With respect to the painting process itself, Honda discovered during the development of the aluminium bodied NSX that the appearance of metallic paint is affected largely by the type and alignment of the aluminium pigment in the basecoat. One way of improving the alignment is to increase the volume shrinkage rate when drying the base coat.

Water borne base coats reflect much higher shrink rates than solvent borne base coats so brightness can be increased by improving the alignment of the aluminium pigment. However it is necessary to evaporate moisture within the paint that is coated to the body before the clearcoat is applied during pre-heat and this has to be done by force drying.

Audi worked with Dürr, Audi’s general paint shop contractor, to develop a highly automated painting process based on a distributed intelligence and higher-level PC based control system. This enabled processes for new paints and car models to be tested and evaluated.

The process revolves around the supply and removal of air, because variations in air quality and temperature in the paint shop and in baking ovens can greatly impact results achieved for the paint finish.

The system needed to cope with the circulation of air via heaters, heat exchangers and heat emission control systems as well being able to supply and remove water needed for cleansing and removing paint residue in a highly coordinated manner.

Proper control of these various parameters is considered essential so that necessary heat treatments for the aluminium alloy can be performed as well as for optimising the painting processes necessary to achieve acceptable quality levels for the finished paint job.

The flexibility this system provided culminated in Audi being able to apply 15 different series colours and numerous special paint finishes to the body of the A8 despite the problems associated with the painting of aluminium panels.

Painting aluminium, car bodies brings with it a whole new set of difficulties to overcome and as can be seen with some of the other developments in various processes, there has been a need for process innovation to accompany product innovation. In common with many of the other process innovations the adoption of computer technology has played a significant role in presenting the opportunity for much needed increases in the automation levels that seem to be essential for making the developments economically viable.