Just been reading an article on automotive metals basically covering that aluminium is closing the gap on market share with steel.
One interesting thing emerges, that in the Audi A8 redesign that the 3.4 metre long side panel, eg the rear wing, C, B, A pillars and part of the roof (basically all the LHS except front wing and doors) is now made out of a single pressing compared to the previous 8 separate parts.
Now I am no expert in body repairs, but it strikes me that any ding to the rear wing and rear lights area could end up mega expensive. Fair enough if you have damage to the pillars then its most likely a major shunt.
But I'd be interested to hear what the backroom thinks. Good or bad
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I am no expert in body repairs either but i heard specialist body shops are needed to fix. Same will apply to the new Jag of course.
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I'd be interested to know how/if this effects the insurance costs. Seems a sign of the times, as manufacturers find ways to cut production costs, repairs become uneconomic. Just look at the way TVs, VCRs, etc. have gone.
Steve.
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Fif
Well, just for a start, making such a single large pressing is likely to increase repair cost even if it were steel, but the added complication of aluminium will increase costs even more. I assume it gives production cost savings, and improved finish, panel gaps etc as the dimensional control is better.
Aluminium is more difficult to panel beat, and certainly more difficult to weld, than steel. So, yes, this is going to be a very expensive car to repair. Also, this may mean that 'back street' repairs are not feasible - keeping the repairs in Audi's control.
Why have they done it? Because they could? I do wonder if the technology is there so it's been used, regardless of cost - either first cost or cost of ownership. After all A8 owners are not going to be short of cash.
Has this achieved much weight saving? I seem to recall the much vaunted use of Aluminium in the A2 actually resulted in a car heavier than it's steel counterparts like the Yaris.
As for aluminium increasing market share, then this is in the face of the modern high-strength steels which are reducing the weight penalty of conventional steels versus aluminium.
Regards
John S
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One of the big problems with the old A8 is the disproportionately high cost of repairing minor dings, so don't be surprised to see a few slightly dog-eared but fundamentally sound used ones around.
Don't know the details, but I think Audi has tried to do something about this second time round as the repair costs have counted against it.
I haven't seen any instances of aluminium being used for genuine weight saving reasons outside suspension set ups. Alloy in the suspension reduces unsprung weight and can improve handling, so it's always worth looking out for it there.
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I seem to recall somewhere that Jaguar made *considerable* weight savings by using aluminium. In fact the need to save weight forced them to use aluminium
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Two points:
o The Aluminium A8 is well-documented for the expensive dings
o Mercedes looked at the process for their larger Mercs and found that the saving of a few kilos would cost a few thousand extra in production costs
rojer@lycos.co.uk
Astra, Renault 18, Renault 25 TXi, Astra Est, Passat Est, Mercedes 190E, Mercedes
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Bit more from the articles. Jaguar with its monocoque XJ claims that joining with self piercing rivets and adhesive joints is the way forward with Aluminium cars. Jag claims the car weighing in at 1565kgs its 40% lighter and 60% stiffer than the steel equivelant.
Audi uses a hybrid laser beam Metal Inert Gas process together with punch rivets, roller hemming and inductive gelling of the glue in tacked joints as their joining processes. That lot will sit very nicely down the local trick shop!
All so Audi can get automation levels above 80% from the previous 20%
Hmmmm, just imagine, you take your brand spankers A8 off to Sainsbo`s for the weekly shop, some dipstick lets a full trolley runaway into your rear wing and there you are 50 miles on the clock and a write off.
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Hmm I expect Audi make repair sections for these dents: they are not THAT stoopid..are they?
madf
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'I seem to recall the much vaunted use of Aluminium in the A2 actually resulted in a car heavier than it's steel counterparts like the Yaris.'
The A2 is not equivalent to a Yaris. I think the reason why so few A2s have been sold is the misconception that it is a direct competitor to 'small' cars such as Yaris, Fiesta, Corsa, Polo etc (hence making it seem expensive). In reality the internal dimensions and luggage space of the car are similar to the Focus, Astra, Golf etc and having owned both a Focus and an A2. An A2 petrol weighs less than 1,000 kg, the diesel just over 1,000 kg. - a lot less then it's true equivalents.
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Don't know about the weight arguments, but again having driven both I certainly didn't get the impression that the A2 had anywhere near as much practical, usable space as a Focus. The reduced weight offers no significant performance advantage, it's expensive for its size. There won't be another, for entirely logical reasons.
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Methinks the marketing bods are responsible:
Fact: Aluminium repairs are more expensive.
Fact: Aluminium cars are more expensive to produce. Extra work is also required to prevent aluminium coming into contact with steel as this causes a corrosive effect.
Fact: Aluminium cars weigh the same/more as the equivalent steel counterpart.
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> Fact: Aluminium cars weigh the same/more as the equivalent steel counterpart
False.
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I should qualify that
The equivalent body shell, given similar rigidity, the aluminium sheel will weigh less - Why do you not think we have steel bodied airplanes flying around?
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Hmm. This reminds me of a school test: which weighs more: a 10lb bag of ballbearings or a 10lb bag of feathers?
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>>Fact: Aluminium cars weigh the same/more as the equivalent steel counterpart.
Not true. They just fill the remaining space with more equipment because they know the engine can handle it. This results in very similar weights.
I wonder how many people realise how much weight they actually add to a car when they stop at a service station. All that stodgy food that they eat and 60/70 litres of fuel at 1KG per litre.
We really shouldn't complain about the extra 100KG here or there.
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Methinks the marketing bods are responsible: Fact: Aluminium cars are more expensive to produce. Extra work is also required to prevent aluminium coming into contact with steel as this causes a corrosive effect.
Just don't break any thermometers near it, either. Mercury LOVES aluminium ...
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Just a couple of points:
The new XJ is nearly 200kg lighter, model for model, than the outgoing XJ. The body is also more than twice as stiff (body torsion). This results in more performance and/or more economy. It also results in better handling and massively reduced opportunity for squeeks and rattles. Most of this weight saving is down to the aluminium body.
Most cars these days have bodysides that are a single full length pressing. Same goes for a whole host of other panels too. Basically reducing the total number of panels in a body results in improved quality (stiffness, fit, rust traps etc) and reduced cost & weight.
Aluminium bodies are more expensive to produce (but the gap is closing), hence very few mass produced ally cars - it's pretty much reserved for cars that can command a premium at the moment.
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"Most cars these days have bodysides that are a single full length pressing."
True but steel isn't an absolute beggar to patch repair like aluminium is, as I have been led to believe.
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Aluminium has been used in the aircraft industry for many years and its properties are well-known to the car makers. In fact many car makers have experimented with aluminium bodies, and continue to do so. In fact Opel (GM) designed an experimental aluminium Ascona which used bonded (glued) panel joints - it worked quite well, apparently.
Aluminium suffers from severe disadvantages though. It corrodes quite easily (ask any airframe inspector!) and suffers electrolytic corrosion in contact with steel (big disadvantage in the car industry). It is relatively inelastic in comparison with steel and so deforms under quite modest forces - hence dents easily. It is then difficult to weld and fillers/paints do not adhere to it that well. I think Audi have set up a handful of specialist body repair centres to handle their cars. Good look to them.
Personally I do not see the point of aluminium bodyshells. Most drivers want vehicles to be *more* resistant to minor damage. Composite materials would seem to be a better route than aluminium.
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I agree with Aprilia on this. Why use aluminium and then have all the associated problems when you can now use composite materials that are rust free, resistant to knocks, easily repairable and just as light as aluminium if not lighter.
I think audi are just using the aluminium thing as a gimmick now as many manufacturers are now choosing composite materials more and more. Even my new Merc's got a plastic boot panel, its light and easy to use, perfect and you just know it won't rust like the old ones.
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The way the manufacturers are going/will go is to use combinations of the above. They will mix and match steels, composite laminates, plastics and alloys. My scenic has plastic front wings. I never knew till i leant on it. The paint is very elastic and has taken several bumps and just springs back with no sign its happened. The aerospace industry has led the way for years and motor manufacturers have been keeping an eye on the technology for years but they wont move forwards unless cost justifications, legislation or marketing forces prevail. All this stuff gets tested on four wheels on various F1 tracks through the year.
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The bonnet and tailgate on the new Volvo V70 are both manfactured from aluminium, also chassis and suspension components by the look of it. Obviously to keep the weight down.
VD5D.
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Saw one at Waterloo, looks wonderful, I've decided SWMBO is going to have one.
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