The new Porsche 911 - designing and supplying lightness for the ultimate sports car

Porsche recently held a presentation on the innovative lightweight design and construction of the new 911. Simon Duval Smith reports and details the purchasing strategies of the Member of the Executive Board for Procurement, Uwe-Karsten Städter

The new 911 features more innovative lightweight components than ever before. The consistently evolved composite design – which now consists of more aluminium, less steel and new composite materials – achieves the extraordinary feat of further reducing the weight of the car, particularly in the cabriolet model by around 7%, without making any compromises in terms of stability, rigidity and safety.

To achieve this, Porsche developers took a different approach by using different plastic materials to create a hybrid design in the A-pillar that guarantees a high degree of occupant protection in the event of the vehicle overturning. This innovative solution replaces the previous tube reinforcements made of super high strength steel. The greatest benefit being that the new reinforcement cuts the overall weight by 2.7 kilogrammes and also lowers the centre of gravity. Both initiatives have a direct impact on the outstanding handling dynamics of the car.

Organo sheet composite solutions

The composite component consists of three elements: a so-called Organo sheet, additional die-cast ribs and a structural foam. Organo sheets are pre-fabricated, extremely sturdy semi-finished products made of fibre-glass reinforced plastic. These sheets are cut and reformed as part of a multi-stage process for use in the 911 Cabriolet. In the same process step, the component is equipped with a ribbed pad made of die-cast plastic. In the last process step, an additional layer of structural foam is added to the hybrid component. This layer expands when exposed to heat during the painting process to thus secure the reinforcement within the A-pillar cross-section. The A-pillar itself consists of super high strength sheet metal components such as boron steel.

Aluminium adds lightness

An increase in the amount of aluminium used lies at the core of the evolved, lightweight design of the new 911 generation – in both the Coupé and the Cabriolet. Apart from the front and rear aprons, the outer skin is now made entirely from this light alloy.

The new door design – made exclusively from aluminium sheet – reduces the weight of the bodyshell without negatively impacting stability and quality. The high degree of toolmaking competence at Porsche is also evident in the sidewall of the Coupé, which is now made of aluminium to cut the overall weight by approximately twelve kilogrammes. This posed the challenge of developing the right tools and processes for the job as, compared with steel sheet, there is a significantly higher risk of tearing when drawing light alloys. A draw depth of around 30 centimetres is achieved during production of the 911 Coupé’s side wall.

In addition to high-strength steels, more extruded aluminium profiles were also used in the bodyshell, such as for the front and rear longitudinal members, inner and outer door sills and floor reinforcements. Their share has been increased from three to 25%. Porsche also uses more die-cast aluminium parts in the new 911, for instance as part of the front spring strut mount, rear tunnel housing, rear longitudinal members and impact absorber mounts. The benefit of die-casting is that even complex, geometrical components can be produced as one single component. Reinforcements or screw connections no longer have to be produced and welded individually. As a result, the component not only becomes lighter, but production steps also become obsolete, making production more efficient. Up to now, one disadvantage of aluminium die-cast parts had been the necessary thermal treatment following die-casting. This step is required to lend components the desired material properties that are crucial for crash performance, for example.

Heat treatment in the paint process

Thermal treatment therefore represented a separate and thus energy and time-consuming step in the production process. In the new 911, Porsche now utilises the temperatures generated during painting processes to perform final treatment of die-cast parts.

Materials and production processes define the ideal connection technology: welding, bonding, clinching, screw connections – no less than ten methods are involved in assembling the body of a new 911. One new feature, for example, is friction welding with countersunk head bolts to link components made of aluminium and steel. In this process, the steel bolt is pressed through the aluminium at such a high speed that friction causes the countersunk head bolts to merge with the steel component, creating a particularly strong connection.

Supplier innovation speeds the new 911

More than 85% of all parts in the eighth-generation 911 are new. As such, Porsche has recruited new production suppliers from the supplier sector to work alongside its trusted strategic partners. Member of the Executive Board for Procurement, Uwe-Karsten Städter, speaks about suppliers new and traditional, and how they have risen to the challenge of improving an already highly successful sports car.

The previous generations of 911 have had very successful management relations and Städter says that the new 992 series of the car was an ideal opportunity to develop existing supplier partners and introduce new ones. “A new car like the 992 provides the ideal opportunity to take on new suppliers and to develop them – which is what we have done. Of course, this new generation cannot and should not be serviced exclusively by new suppliers, as our long-standing strategic partners are also a vital part of our plan to ensure that we maintain and improve the high quality standards of the 911. As is appropriate to the heritage of the 911, we will draw on our many years of experience and make best use of the current innovations offered by our suppliers.”

New 911 - new quality standards and early supplier involvement

As the 911 has developed over its generations, so the automotive world has evolved, with new systems and quality standards, as Städter says, “Fundamentally, the quality standards we work to are extremely high for all our vehicles, especially the 911, so we work very closely with authorised partners on whom we rely to meet quality requirements, with all departments also participating. Supplier selection is the culmination of a very complex process that involves colleagues from Development, Production, Quality, and Production Series; we all play our part in selecting the best suppliers. The whole process, including the decision and contracting of our suppliers, is the first step towards ensuring that the project is a success for all of us.”

Städter says that Porsche does involve its suppliers in projects as early as possible, “We have the objective of benefitting from our combined knowledge, steering development in the right direction, and making sure we are on the same page in considering technically complex components right from the start,” he says, adding: “We also conduct concept workshops in-house, supporting these outcomes. Working with our suppliers, we have been able to put a car on the road that makes driving even more enjoyable and smarter – even in its eighth generation. Nothing has changed in terms of how we award contracts to partners, and our focus remains firmly on ensuring commercial success.”

Innovation Days and supplier workshops

In terms of new strategies or requirements for suppliers, a transparent information policy, supplier action days, or quality reviews, Städter says that during the OEM’s Innovation Days, pre-selected suppliers are given the opportunity to present new ideas to different departments in the development centre at Weissach. “We do this so we can identify the best and most innovative ideas, and provide support for any preliminary development by working with suppliers at a early stage. A validation and innovation process made up of several stages helps us assess the prospects for collaboration with cross-functional teams. Quality aspects are also scrutinised, and the process is designed to create the best possible technical and commercial conditions for realising the idea, as well as building a foundation for continued close collaboration.”

Teamwork - strategic and exclusive suppliers and working with engineering

Speaking on the thorny issue of whether Porsche retains exclusive suppliers for specific parts that are especially high-volume or highly complex, or are those contracts open to new vendors, Städter says that, “Our suppliers are normally contracted only to provide their specific part. Of course there are certain strategically important components that are key to the power output and performance of the vehicle, but the supplier portfolio is not chiefly a strategic tool. For us to prepare the vehicle for series production, it is key that contracted suppliers properly apply their expertise to meet our requirements and understand the vehicle’s complexity.”

The relaitonship between purchasing and R&D and engineering departments is often not as close as it might be but at Porsche, Städter says that, “New projects and quality demands can only be fulfilled with collaboration from all departments, so it’s not that Procurement is the gatekeeper here. The company as a whole is responsible for ensuring that the entire project is completed and meets customer requirements within a sound technical and commercial framework. We believe it is absolutely essential that we work together as a team.”  

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