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Plastic Components Couldn't Take the Heat

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GlennA
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Environmental design specifications
GlennA   6/22/2012 10:18:17 AM
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My friend is a Jaguar fan.  A few years ago he finally got to buy a Jaguar.  He was telling me he had to replace a part of the dashboard.  His theory was that Jaguar designed the car according to the weather in England = very few hot and sunny days.  So, in a climate of many hot and sunny days, the dash didn't survive.  Perhaps the Audi problem is a similar climate difference effect.

Ann R. Thryft
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Re: Environmental design specifications
Ann R. Thryft   6/22/2012 12:27:21 PM
Considering all the checks and balances in automotive production and the amount of testing required when new materials are introduced, I'm always surprised to hear that something like this gets through. Texas can be very hot, but it sounds like the model didn't account for those heat extremes. Or it was a model built for one region, as Glenn's comment suggests, but sold in another region. Some Made by Monkeys columns, like this one, should perhaps be titled "Fixed by Clever Humans."

krik
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Iron
Re: Environmental design specifications
krik   6/22/2012 3:28:53 PM
Clever may not be the best description, curious is.  Being a design engineer by trade, a faulty design is like a challenge to a duel.  To win the duel, the design modification needs to have superior durability while not taking excessive time, money or effort to implement. Realistically, these faulty designs are an excellent opportunity to baseline various approaches, observing practices that work well and others which don't.

 



Charles Murray
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Re: Environmental design specifications
Charles Murray   6/22/2012 5:23:34 PM
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I like you suggestion for the name of this blog, Ann. "Fixed by clever humans" is what this is really all about. I, too, am surprised that something like this happened. I'm not sure, but I believe that most of these automotive parts are designed for temperatures ranging from minus 30C to +70C (could a reader with expertise please weigh in here?), which would mean that it would be designed for about 160F on the upper end. Seems like this shouldn't have happened, even in the Texas heat. 

neum69
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Iron
Re: Environmental design specifications
neum69   6/25/2012 9:51:46 AM
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Automotive design specs for components like this require operation in ambient temps of -40 to 105C.

lmolleda
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Iron
Re: Environmental design specifications
lmolleda   6/25/2012 9:58:02 AM
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You are right that the type of failure should have not happened in Texas, or Arizona or any extreme heat or extreme cold area. The requirements for the American OEMs and one Japanese OEM that I have worked until now always state the extremes in temperatures and years that the designs should stand. It is usually well beyond what you would expect to usually have. Components are sold and rated for consumer grade, automotive grade or military grade, and design should usually give margin to in worst cases still stand the extremes for what they are rated. Also parts are requested to be validated with stringent and accelerated tests to ensure that vehicle parts should stand 10-15 years at extreme swings. The design of that part might have missed a good validation that would have identified early wear, or based on business or management decisions to allow to go to the field with a failed design and let them catch in warranty the failed parts and save on a costly redesign. 

Ann R. Thryft
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Re: Environmental design specifications
Ann R. Thryft   6/25/2012 12:18:25 PM
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Re curiosity vs cleverness, I was assuming pre-existing curiosity, expertise and a few other things on the part of the clever fixer, otherwise he/she couldn't express their cleverness and provide a useful fix. Re UK temps, parts of northern Scotland are pretty darn cold in the winter, down to an average of 1C or below, but that may not be low enough for testing purposes.

thrashercharged
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Re: Environmental design specifications
thrashercharged   6/25/2012 4:01:23 PM
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"Re UK temps, parts of northern Scotland are pretty darn cold in the winter, down to an average of 1C or below, but that may not be low enough for testing purposes."

1 deg C?  Oh no, that's not nearly cold enough!  1C is almost considered tropical in some areas of the north!  When it warms up to above freezing for the first time in the Spring we start wearing T-shirts, really!  -40 is the typical cold standard.  Most car manufacturers have a hot and cold weather proving grounds.  GM's cold weather proving grounds is in Kapuskasing, Ontario, Canada.

 

Ann R. Thryft
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Re: Environmental design specifications
Ann R. Thryft   6/26/2012 12:58:34 PM
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Thanks, thrashercharged, I didn't really think 1 deg C was low enough based on what Chuck and others had said. Now I'm curious--where are you writing from?

gsmith120
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Platinum
Re: Environmental design specifications
gsmith120   6/24/2012 6:02:30 PM
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Some times companies are a little more relaxed on testing certain things because a failure in that are would not be fatal and less testing would save some money.

 

Rob Spiegel
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Re: Environmental design specifications
Rob Spiegel   6/22/2012 2:47:22 PM
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Since it seems to be getting hotter everywhere these days, this may be a problem that automakers will have to address.

Amclaussen
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Platinum
Re: Environmental design specifications
Amclaussen   6/22/2012 3:44:30 PM
"Designed for"???

Wait a minute; if any car company designes its products for a mild climate only, it would almost be called a fraud!  I would say that it is a case of SLOPPY design, more that anything. In order to withstand the required mechanical stress in this type of assemblies, both the plastic part and the metal one have to be designed and fabricated properly.  Asembly fixtures also play a part, as the melting tool too. Most commonly, the metal part is badly manufactured, since the punching leaves small, sharp edges that easily cut and erode the plastic bosses that are already stressed by the assembly heating-cooling cycle, which causes modified properties, different from the rest of the molded plastic part, then the bosses break easier than desired.

Your solution (to use small metal screws for plastic assemblies is the best way to ensure a proper, well joined assembly, well sealed from rain and spray. I woul write to the car maker; otherwise cars will be made even more sloppily every year.

GlennA
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Gold
Re: Environmental design specifications
GlennA   6/22/2012 3:55:32 PM
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Amclaussen; I have read articles about how U.S. car manufacturers will do cold weather testing in the Dakotas, where very cold winter weather is readily available.  And very hot summer weather is available in the southwest states.  I don't think the U.K. has such weather extremes readily available.  (Are there U.K. climate experts reading to comment ?)  So it may not be a matter of designing for a mild climate, so much as the climate where the teating is done is mild, so the failures due to extreme climate are not seen during testing.  Does anyone know if Jaguar or Audi have climate chambers to similate extreme climates ?

Rob Spiegel
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Re: Environmental design specifications
Rob Spiegel   6/22/2012 4:06:51 PM
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That's a very good question, GlennA. I would guess it depends somewhat on the size of the foreign market. Does the size of the market warrant testing outside the expectations of the core market? If the U.S. market is 2 or 3 percent, they may not see it as economically feasible to test for the market or design for the market.

Amclaussen
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Re: Environmental design specifications
Amclaussen   6/22/2012 3:51:13 PM
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Well, Jaguar is an expensive brand that has many issues... I would suppose that a Typical owner would want to keep a Jaguar car for several years; so that a badly damaged dashboard is inexcussable!  Poor, insuficient design and testing by Monkeys-R-Us.

gsmith120
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Platinum
Re: Environmental design specifications
gsmith120   6/24/2012 5:41:43 PM
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I have a VW Passat and it appears that some of the odd things/features were not design for American drivers.  However, some of the odd features don't make any sense to me at all.  For example, when any of my outside lights go out (as they like to do so often) I get no warning however the car find it necessary to keep warning to "top up" my windshield wiper fluid when it is low.  I'm thinking really it's more important to keep reminding me to put washer fluid in the car but not important to tell me one of my outside lights are out.  Maybe this isn't a big deal other places but in MD cops will stop you for a light being out.

KingDWS
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Gold
Re: Environmental design specifications
KingDWS   7/10/2012 3:48:58 PM
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It isn't just Audi or Vw etc they also do the same stuff in Mercedes. I just replaced the dash light bulbs ($1 at Napa or $20 from the stealership same bulb, same brand etc) and the sockets were either scorched or melted. Of course the dealer er stealer will tell most customers that they need a new dash assembly (don't have enough room to put the price of that in one post). Unfortunetly it seems most customers are of the type that they can fix anything using only a credit card or checkbook and the problem goes away. Some of the rest of us who have an idea whch end of a screwdriver or soldering iron to hold are converting to LED's. That isn't as straight forwards as it seems. Mercedes has designed the systems so that they detect the current load so if you don't get things right you get light but still get a light out light unless you are lucky to have that one burnt out as well !

Funny all through school up to university not one person ever told me there are monkeys in Germany ;-]

rdelaplaza
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Silver
Re: Environmental design specifications
rdelaplaza   7/11/2012 1:23:15 AM
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BAD NEWS.. not only Audi but also ANYTHING... CHRYSLER; it happens to the  Caravan, Voyager, Jeep Cherokee... the double filament rear light bulb that act as Rear lights and Brake lights, is mounted in a plastic bulb holder that has a bayonet style mount into the rear lamp assembly connected to the car electric system, well the bulb holder has 3 sliding contacts that touch the lamp assembly, well it seems that the current flowing to the bulb, gets the whole thing  hot enough to scorch the bulb holder and melt the lamphoder where the contacts touch, resulting in NO brake light or tuning light or working rear lamp ===  DEALER solution : to replace (BUY $)  the whole rear lamp assembly. ...

Talking about monkeys designing stuff... ! ! !   planned obsolescence, or plain stupidity.

My solution... solder 3 wires (1 regular rear light filament, 2 brake light filament and 3 ground) to the lamp holder, and connect them directly to the electric system wires spliting the insulation were the wires go into the connector. you have to know what you are doing but it solves the problem and works forever.

Liquefactionist
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Iron
Saturn did a recall for this
Liquefactionist   6/22/2012 10:42:07 AM
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I used to own a Saturn LS series sedan.  It had the same injection molded light assemblies.  It had the same failure (many stops by police for taillights out ensued).  I went to the junk yard to get new assemblies as mine became pitted from the poor contact.  I found a car with another harness attached to the light assembly that converted back to the more traditional plug in method of connecting lights.  It seems there was a quiet recall on this.  Maybe Audi has the same thing going on.

j-allen
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Gold
Brake light failure
j-allen   6/25/2012 9:36:42 AM
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First off, a brake light failure IS a safety problem.  Second, there is no excuse for a bulb socket that melts, even in Texas.  We have been making such sockets for about 100 years with proper insulators such as Baeklite, phenolic, and ceramics, and also reliable conductors such as brass and bronze.  These materials are still quite adequate.   No excuse.   The engineer responsible should be publically whipped. 

ratkinsonjr
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Re: Brake light failure
ratkinsonjr   6/25/2012 9:47:39 AM
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You are correct, brake light failure is a safety violation, not only at a state level, but at the Federal level as well. You can report an incident to the National Highway Traffic Safety Administration (NHTSA) using an on-line form at:

 

https://www-odi.nhtsa.dot.gov/ivoq/

 

If enough people report a problem, NHTSA can force a recall. This is a bigger problem than just the Audi A3, since the Audi A3 and the Volkswagen Golf share the same platform and may have a similar issue. Even if the taillight assemblies look different, they may use the same construction from the same supplier (likely Hella or Bosch).

Shelly
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Iron
Re: Brake light failure
Shelly   6/25/2012 10:40:39 AM
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That sounds like approximately the same design as the taillights on my BMW, made by Hella.  I am constantly fighting with continuity issues with the integrated ground circuit.  I have gone to the extremes of soldering on little ground wires to individual bulbs sockets that have been giving me the most greif.

The car will warn me when a brake or tail light is not working, which is convenient, but that integrated ground design was junk IMO.  I didn't see any melting or heat related problems on mine, but just keeping the bulbs tight enough and the continuity flowing through the entire metal frame on the back of the lens to each bulb is bad enough.

Larry M
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Platinum
Re: Brake light failure
Larry M   6/25/2012 11:42:18 AM
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It isn't only Audi.  GM seems to have abandoned the classic bayonet-base parking and tail lamps (like 1034) for this special push-in 3157 lamp. The white plastic housing on every one I've seen is scorched.

robatnorcross
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Re: Brake light failure
robatnorcross   6/25/2012 5:25:27 PM
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J-Allen thinks the engineer should be publically whipped. I think the engineering (and higher) management needs to be tortured.

I've been involved in too many projects where NO time was allocated for testing/debugging. If the thing looks good the first time the management is ready to move on. I'm all for designing something as close to the final product as possible but a lot of engineering departments already have the NEXT project to shift you to and leave no time for a second rev.

I suspect that the plastic compound that ended up in the tail light assy. probably cost 10 cents per pound less than the one they had been using for 20 years.

Rob Spiegel
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Re: Brake light failure
Rob Spiegel   6/27/2012 3:46:57 PM
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When I started out, my first professional job was working in an automotive paint lab in Detroit. Knowing that the cars would experience the combo of salt and humidity in climates such as Florida, we did saltwater testing on the paint. Seems a no-brainer to test for all of the potential environments customers will use the products.

Rob Spiegel
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Re: Brake light failure
Rob Spiegel   6/27/2012 3:46:58 PM
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When I started out, my first professional job was working in an automotive paint lab in Detroit. Knowing that the cars would experience the combo of salt and humidity in climates such as Florida, we did saltwater testing on the paint. Seems a no-brainer to test for all of the potential environments customers will use the products.

OLD_CURMUDGEON
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Platinum
SLOPPY ENGINEERING & DESIGN
OLD_CURMUDGEON   6/25/2012 10:12:57 AM
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I  beleive that there is so much pressure on design engineers in general now that there is insufficient life testing being done.  I think too many times designers take the word of suppliers' tech reps regarding the qualities of a base item, such as a plastic resin, and run with it.  Since AUDI & JAGUAR are global companies, I would suspect that there are many vehicles w/ their nameplates travelling the highways NOT ONLY in Texas & Arizona, but also like places in Dubai, Saudi Arabia, Turkey, the Middle East, etc. where summer time temperatures are even hotter than those of the Southern U.S. states.  So, in essence it would seem that there is absolutely NO EXCUSE for more complete testing of components that go into products destined for these climates.

averagejoe72677
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Re: Environmental design specifications
averagejoe72677   6/25/2012 2:14:57 PM
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While plastics have come a long way in the last decade or so. there are just certian components that exceed the capabilities of even the best plastics. Light bulb assemblies in this case are a classic example. Had the manufacturer chosen LED lights instead of high heat conventional bulbs, this may have worked fine. Apparently verification testing has gone by the wayside in favor of cost cutting.

 Other components that makes me nervous are plastic valve covers and intake manifolds. they may work fine for a few years until the warranty expires, but eventually time and thermal cycles will do them in, leaving the owner footing the bill for replacement parts.

 

  

Tim
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Platinum
Surprise with Audi
Tim   6/29/2012 6:37:27 PM
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I was surprised to see that this failure was on an Audi. Audi is a high dollar vehicle that you would not expect to see a failure like plastic creep. Unfortunately, limitations of plastic as compared to metal are not always taken into account when metal replacement projects are completed.

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