GM claims 'breakthrough' will make vehicles lighter, help gas mileage

[lfeg]

Spot welding is cheaper than rivits.

 

The other issue is speed. Spot welding sequence is clamp, zap, release. Very fast. Riveting is clamp, drill, insert, clinch, release. The insert step requires as much time as the spot weld zap, clinch also takes about as much. And that is if a mandrel type self cliching rivet is used. This gives a protruding rivet on both sides. Other types of rivets tale longer.

 

No problem for a low volume premium car, but a huge issue for something like Fiesta, Focus, or Fusion.

[RangerM]

A metal worker I knew once told me that welded aluminum is always weaker than the parent metal. I'm assuming this was based on experience, but is the message of GM's accidental discovery that this is no longer true? (assuming it was)

[Pioneer]

A metal worker I knew once told me that welded aluminum is always weaker than the parent metal. I'm assuming this was based on experience, but is the message of GM's accidental discovery that this is no longer true? (assuming it was)

 

Not true. We had to break down the hoods nightly to test the welds. The welds were stronger than the parent metal.

[Pioneer]

 

 

The other issue is speed. Spot welding sequence is clamp, zap, release. Very fast. Riveting is clamp, drill, insert, clinch, release. The insert step requires as much time as the spot weld zap, clinch also takes about as much. And that is if a mandrel type self cliching rivet is used. This gives a protruding rivet on both sides. Other types of rivets tale longer.

 

No problem for a low volume premium car, but a huge issue for something like Fiesta, Focus, or Fusion.

 

Speed is all in the execution. The hood line over in Stamping runs twice as fast as the front door lines. The hoods are rivited, the doors are welded. Instead of using one rivit gun doing many rivits, like the weld guns do welds, they have many rivit guns in one fixture.

[fordmantpw]

Not true. We had to break down the hoods nightly to test the welds. The welds were stronger than the parent metal.

 

Speed is all in the execution. The hood line over in Stamping runs twice as fast as the front door lines. The hoods are rivited, the doors are welded. Instead of using one rivit gun doing many rivits, like the weld guns do welds, they have many rivit guns in one fixture.

 

I must say, it's nice to hear your first-hand experience with things like this.

[RichardJensen]

Spot welding is cheaper than rivits.

So then, the next question would be whether spot-welding per this particular process is cheaper than riveting aluminum.

[rkisler]

The other issue is speed. Spot welding sequence is clamp, zap, release. Very fast. Riveting is clamp, drill, insert, clinch, release. The insert step requires as much time as the spot weld zap, clinch also takes about as much. And that is if a mandrel type self cliching rivet is used. This gives a protruding rivet on both sides. Other types of rivets tale longer.

 

No problem for a low volume premium car, but a huge issue for something like Fiesta, Focus, or Fusion.

 

The rivets used are self-piercing, so no drilling is required.

[rkisler]

So then, the next question would be whether spot-welding per this particular process is cheaper than riveting aluminum.

 

There are two or three advantages to spot welding aluminum (if you can get it right) vs. self-piercing rivets:

 

1. Speed; although the rivets are inserted by robots that look very much like those that hold electrodes for welding, there is some difference in speed. Not a big deal on a Jaguar XJ, but could be on a higher volume model.

 

2. Cost -- IIRC, the self-piercing rivets cost about $0,01 each. So if you look at the rivet count of 2,500-3,000 per car, that's $20-$30. You would sell your grandmother and maybe your firstborn for that in the auto industry.

 

3. Weight -- I don't know how much the total rivet weight is, but it ain't nothin'

 

There might be some offsets in the energy side as I seem to remember that welding in aluminum is more energy intensive than steel (I stand to be corrected on this one). When Jaguar decided on rivets for the XJ, energy was a concern, particularly if all the weld guns happened to be firing at the same time in the body shop; would have required software/hardware to phase welding process IIRC.

 

Also, adhesives have been mentioned. Lotus used adhesives, and in some cases had a "tear off tab" that could be used for testing as there is no good way to do non-destructive testing on the finished product. But I would think that adhesives have progressed to an extent where you don't have to do testing on fabricated parts? Still adhesives aren't good for everything, and some parts need to be joined by rivets or welds.

 

It was nice to see Pioneer's comments which provide good insight

[Edstock]

particularly if all the weld guns happened to be firing at the same time in the body shop;

 

That's a lot of current.

[RichardJensen]

IIRC, the self-piercing rivets cost about $0,01 each.

Is that a typo, or are your Continental roots showing through?

[rkisler]

Is that a typo, or are your Continental roots showing through?

 

Oops. Very funny. No, I'm the furthest thing from continental. But my eyesight isn't great; I think my next laptop needs a lighted keyboard!

[RichardJensen]

I'll be very curious to see what Ford does with the F150. Especially since the first month's sales of the aluminum F150 will probably come close to equaling the total number of aluminum bodied vehicles sold in the US during the previous year.

[jpd80]

I'll be very curious to see what Ford does with the F150. Especially since the first month's sales of the aluminum F150 will probably come close to equaling the total number of aluminum bodied vehicles sold in the US during the previous year.

Holy cow, that's probably right.

I wonder whether that will encourage Ford to do more Aluminum versions of other platforms like D3....

That one change could make a huge difference to future vehicles like Explorer and maybe Taurus..

[Pioneer]

 

I must say, it's nice to hear your first-hand experience with things like this.

 

Thank you.

[procyon]

Not true. We had to break down the hoods nightly to test the welds. The welds were stronger than the parent metal.

The weld material itself may be stronger in yield or tensile than the parent material when exposed to a single load cycle. However, fatigue life of the weld will always be shorter than the parent metal.

[Anthony]

I thought Ford shot down the aluminum F-150 rumor?

 

http://news.pickuptr...-the-works.html

 

This morning Ford called the Wall Street Journal's suggestions "premature." The company said it is looking at many ways to reach the 54.4 mpg target by 2025 and that a fully aluminum pickup truck is likely to have many things working against it.

 

Or was there something that occurred after this that I missed? Or do we think they are just trying to keep it secret?

Edited October 1, 2012 by Intrepidatious

[NickF1011]

I thought Ford shot down the aluminum F-150 rumor?

 

http://news.pickuptr...-the-works.html

 

 

 

Or was there something that occurred after this that I missed? Or do we think they are just trying to keep it secret?

 

I think it was Fields who hinted at something about the F-150 a week or so ago at his presser for the COO promotion. It was nothing specific though.

[SoonerLS]

Or was there something that occurred after this that I missed? Or do we think they are just trying to keep it secret?

I don't have time to track it down at the moment, but I remember reading something recently about Mulally saying something about using more aluminum (how's that for definitive?) in the construction of upcoming Fords, possibly in Automotive News. For all I remember, the link could be somewhere in this very thread.

 

I know the rumors in GM circles are that the next Sierraverado will use a lot of aluminum construction, so Ford can't be very far (if at all) behind.

[RichardJensen]

I thought Ford shot down the aluminum F-150 rumor?

Look closely. Ford said that the report of a fully aluminum F150 was 'premature', and in any event, I don't think anyone seriously believes that the next F150 will have an aluminum frame. It's a classic non-denial denial.

Edited October 1, 2012 by RichardJensen

[SoonerLS]

Here's the quote I mentioned above:

Asked about a report that the next-generation F-150 could be mostly aluminum' date=' Mulally said the company has been "adding more aluminum. I can tell you as an airplane person, aluminum is very durable and very strong. And the neat thing about this is that it brings such a reduction in weight ... We're going to see more and more of these alloys going forward," he told CBS.

-- http://www.detroitnews.com/article/20120918/AUTO0102/209180375 [/quote']

It's linked in a thread here, I think, about Mulally's "don't write me off yet" quote.

[lquidspine]

There was a big write-up of the Lincoln LS in some technical journal a few years ago because they used some kind of innovative metal adhesive in a joint about half-way up the C-pillar. Maybe it was a mixture of adhesives and welds; it has been a few years since I saw it.

Only thing I can think of here is what we called Spray Brazeing basically instead of having a seam on the roof line that meets the body side, the roof would only be spot welded in the DOP. The roof would overlap the C-pillar were it would get wire welded and ground down and then we would spray brazy the A-surface joint on the C-pillar and grind it down flush.

 

This process was used on the Continental as well as the LS, however the LS joint was huge compareed the Continental joint. Simply look at a dark colored LS on the C-pillar and you can see some waveyness as a result of such a big joint.

 

Sorry if this has been answered already I did not have the energy to go thru all 3 pages.