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Post by wvengineer on Aug 1, 2014 13:00:49 GMT
I read an article where Ford is switching to Aluminum instead of steel for the body of the 2015 F-150 truck. The result was a 750 lbs weight reduction. With increasing fuel economy requirements for cars, weight savings is a primary focus of many auto makers.
I was wondering how practical it would be for auto makers to bring back plastic body panels. MY parents got a 1998 Saturn station wagon that had the plastic panels. My sister now has that car and despite being 17 years old, the body is still in good shape, unlike the engine and interior. Those panels have survived a whole lot of abuse.
So with automakers needing ways to save weight, why not bring back the plastic?
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Post by craighudson on Aug 1, 2014 16:02:12 GMT
Does plastic absorb much energy in a crash?
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Post by OziRiS on Aug 1, 2014 19:44:06 GMT
Does plastic absorb much energy in a crash? Guess that would depend on how you built it. I bet you could make crumple zones in plastic, much like they do with steel and aluminum and still keep the weight down. |
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Post by mrfatso on Aug 1, 2014 22:25:57 GMT
Some cars do for example the Lotus Elise, is made from Glass Reinforced Plastic, it's probably most common in sports cars rather than a family saloon though.
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Post by Cybermortis on Aug 1, 2014 23:03:11 GMT
Plastic comes from crude oil, so its not as environmentally sound as using metal.
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Post by OziRiS on Aug 1, 2014 23:17:20 GMT
Plastic comes from crude oil, so its not as environmentally sound as using metal. Could use recycled plastic. There's definitely enough of it lying around these days. |
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Post by wvengineer on Aug 2, 2014 0:31:50 GMT
Does plastic absorb much energy in a crash? As apposed to the thin sheet metal they would be replacing? Body panels are small absorbers compared to the frame and engine. Plastic comes from crude oil, so its not as environmentally sound as using metal. Well, how much oil does it take to make the body panels vs. how much gas you save by the reduced weight over the life of the car? Someone would have to run the calculations, but I suspect that the end result would be a net savings. |
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Post by Cybermortis on Aug 2, 2014 9:31:29 GMT
Does plastic absorb much energy in a crash? As apposed to the thin sheet metal they would be replacing? Body panels are small absorbers compared to the frame and engine. Plastic comes from crude oil, so its not as environmentally sound as using metal. Well, how much oil does it take to make the body panels vs. how much gas you save by the reduced weight over the life of the car? Someone would have to run the calculations, but I suspect that the end result would be a net savings. Here is an interesting little factoid for you; Recycling aluminum uses only 5% of the energy needed to produce it from ore. Recycling plastics uses 30% of the energy needed to make new plastic. You also have to consider the amount of material you'd have to produce for repairs. An aluminum panel that takes a minor hit will be dented, and potentially can be beaten back into shape. A plastic panel that takes the same hit will most likely crack, and have to be replaced - unless you make the plastic very thick, which kind of defeats any material or weight savings. |
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Post by the light works on Aug 2, 2014 11:02:47 GMT
As apposed to the thin sheet metal they would be replacing? Body panels are small absorbers compared to the frame and engine. Well, how much oil does it take to make the body panels vs. how much gas you save by the reduced weight over the life of the car? Someone would have to run the calculations, but I suspect that the end result would be a net savings. Here is an interesting little factoid for you; Recycling aluminum uses only 5% of the energy needed to produce it from ore. Recycling plastics uses 30% of the energy needed to make new plastic. You also have to consider the amount of material you'd have to produce for repairs. An aluminum panel that takes a minor hit will be dented, and potentially can be beaten back into shape. A plastic panel that takes the same hit will most likely crack, and have to be replaced - unless you make the plastic very thick, which kind of defeats any material or weight savings. the selling point on Saturns was that the plastic body panels were virtually dent proof - unless you hit it hard enough to bend the structural members, the plastic would just spring back - whereas modern sheet metal is so thin, it is very difficult to straighten. one of the initial selling points for the Smart was that the plastic body panels clipped on - so "bodywork" was done by ordering the replacement panel, unclipping the damaged panel, clipping on the new panel, and sending the old panel back in the shipping box - postage paid by the dealership. |
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Post by wvengineer on Aug 2, 2014 11:54:26 GMT
Here is an interesting little factoid for you; Recycling aluminum uses only 5% of the energy needed to produce it from ore. Recycling plastics uses 30% of the energy needed to make new plastic. You also have to consider the amount of material you'd have to produce for repairs. An aluminum panel that takes a minor hit will be dented, and potentially can be beaten back into shape. A plastic panel that takes the same hit will most likely crack, and have to be replaced - unless you make the plastic very thick, which kind of defeats any material or weight savings. Apples and oranges comparison there as stated. 5% of what vs. 30% of what? Again, I don't have the numbers off the top of my head, but due to the initial electrical cost of aluminum being sooo high, the energy costs are still likely a wash between the two. |
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Post by the light works on Aug 2, 2014 13:32:39 GMT
Here is an interesting little factoid for you; Recycling aluminum uses only 5% of the energy needed to produce it from ore. Recycling plastics uses 30% of the energy needed to make new plastic. You also have to consider the amount of material you'd have to produce for repairs. An aluminum panel that takes a minor hit will be dented, and potentially can be beaten back into shape. A plastic panel that takes the same hit will most likely crack, and have to be replaced - unless you make the plastic very thick, which kind of defeats any material or weight savings. Apples and oranges comparison there as stated. 5% of what vs. 30% of what? Again, I don't have the numbers off the top of my head, but due to the initial electrical cost of aluminum being sooo high, the energy costs are still likely a wash between the two. and new metal is made out of rocks - which are not any more renewable than dead dinosaurs - but evil scientists are working on ways to make plants produce the raw materials for plastic. |
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Post by wvengineer on Aug 2, 2014 16:33:39 GMT
With the rise in oil prices, hydro-polymerization plants are getting to be more popular. The idea is that they can take just about any carbon source (used tires, paper, animal carcases, etc) and water and turn it into NG, gasoline, and light crude oil, the NG is used to maintain the process. It is expensive to setup, so it fell out of favor when prices dropped, but people are getting back into it. One of the automation contractors I work with are in the process of building a plant for this. We'll see how it progresses over the next few years.
Additionally, there is bioplastic.
I guess I am wondering why Saturn stopped using the plastic panels and why it never caught on elsewhere.
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Post by the light works on Aug 2, 2014 16:52:38 GMT
With the rise in oil prices, hydro-polymerization plants are getting to be more popular. The idea is that they can take just about any carbon source (used tires, paper, animal carcases, etc) and water and turn it into NG, gasoline, and light crude oil, the NG is used to maintain the process. It is expensive to setup, so it fell out of favor when prices dropped, but people are getting back into it. One of the automation contractors I work with are in the process of building a plant for this. We'll see how it progresses over the next few years. Additionally, there is bioplastic. I guess I am wondering why Saturn stopped using the plastic panels and why it never caught on elsewhere. I would guess it has to do with the fact there stopped being new Saturns to put them on. |
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Post by wvengineer on Aug 3, 2014 0:57:22 GMT
My parent's '98 SW1 had the plastic body panels, but a coworker of mine has a much newer Vue with an all steel body. I would guess somewhere in the mid 2000's they went back to steel.
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Post by the light works on Aug 3, 2014 1:19:59 GMT
My parent's '98 SW1 had the plastic body panels, but a coworker of mine has a much newer Vue with an all steel body. I would guess somewhere in the mid 2000's they went back to steel. I think they went with steel for the Vue since it was a shared platform. |
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Post by OziRiS on Aug 3, 2014 1:48:32 GMT
I guess I am wondering why Saturn stopped using the plastic panels and why it never caught on elsewhere. My parents had a 98 Ford Mondeo where both the front and back bumpers were plastic. We didn't know it was plastic until it needed replacing, after my older brother got too close to a high curb and ripped the front bumper in half trying to get back off of it. It was pretty expensive to replace though. Don't know why... |
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Post by silverdragon on Aug 3, 2014 11:58:18 GMT
If you look at the Motor industry, you get this... Yes, a body panel that is just one big (safe) battery.... I know, its Volvo again, I cant seem to get away from them... but... www.geeky-gadgets.com/volvo-develops-carbon-fiber-car-body-panels-with-nano-batteries-18-10-2013/The basic principal is replace the body panels with something that is strong and durable but also can store energy. The panels will be over a crash proof almost roll cage design for strength, so they are just there to keep the weather on the outside, but if the can be used for something else?... why not?..... Plastic panels, yes, weight saving, I agree, bloody good idea. Make the panels some sort of safe way of helping the propulsion system?... My head explodes.... the smart-(donkey)'s... thats an even better idea innit?.... credit due for thinking not just outside the box but on a completely different reality. |
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Post by wvengineer on Aug 3, 2014 14:03:19 GMT
I guess I am wondering why Saturn stopped using the plastic panels and why it never caught on elsewhere. My parents had a 98 Ford Mondeo where both the front and back bumpers were plastic. We didn't know it was plastic until it needed replacing, after my older brother got too close to a high curb and ripped the front bumper in half trying to get back off of it. It was pretty expensive to replace though. Don't know why... Most cars today have plastic covers over the bumpers. The bumper itself is a steel or aluminum beam with a plastic body panel over it. Every car I have owned has this. My understanding is that is done for two reasons. 1. Stamping sheet metal into the complex shape of the bumper and front grill is very difficult without doing it in multiple pieces (doesn't look as good) or having a high failure rate. 2. Bumpers are made to be beatup. Plastic can take the abuse and still look good whereas metal cannot. I was in a small ice related accident early this year that messed up the front bumper of my Ford Fusion, among other damage. When deciding if it was worth it to fail a claim or not, I looked at replacing it myself because the work would be easy for me and I know people who could paint it for cheap. The bumper cover was about ~$200, but shipping was a killer at an additional $175 because of oversized shipping costs. |
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Post by the light works on Aug 3, 2014 14:08:53 GMT
If you look at the Motor industry, you get this... Yes, a body panel that is just one big (safe) battery.... I know, its Volvo again, I cant seem to get away from them... but... www.geeky-gadgets.com/volvo-develops-carbon-fiber-car-body-panels-with-nano-batteries-18-10-2013/The basic principal is replace the body panels with something that is strong and durable but also can store energy. The panels will be over a crash proof almost roll cage design for strength, so they are just there to keep the weather on the outside, but if the can be used for something else?... why not?..... Plastic panels, yes, weight saving, I agree, bloody good idea. Make the panels some sort of safe way of helping the propulsion system?... My head explodes.... the smart-(donkey)'s... thats an even better idea innit?.... credit due for thinking not just outside the box but on a completely different reality. think what would happen if they then overlaid them with thin film solar cells... (you know, the kind that are less efficient, but way more cheap and durable) |
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Post by wvengineer on Aug 3, 2014 14:19:32 GMT
Doing some reading, part of Saturn's problem was the cost of the plastic panels. They were made from a combination of ABS and polycarbonate plastic that had the same color though the thickness of the plastic. This PC/ABS had a bad reputation of not flowing well in molds and having runs and flows that messed up the color. This lead to high loss rates that drove the prices up. Also, because you have to run different plastic mixes for each color of car, you high production costs because you have to maintain complete inventories of body panels for every color. This also limits the colors you can make cars in.
Thinking about the above, all the plastic bumper covers I have worked with other than my parent's Saturn use a primer color plastic (usually black) that is than painted to match the rest of the car's body. So at least one thing that could be done for an all plastic car today to reduce costs is to skip the molded color panels and just have one panel set that is painted to whatever color you what.
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