Automotive lightweighting is a big deal these days in the world of plastics, with US Corporate Average Fuel Efficiency (CAFE) requirements that will force automakers to jack up mileage to 35.5 mpg by 2016, and to 54.5 mpg by 2025. Major plastics manufacturers are responding with new formulations to achieve these drastic reductions in fuel consumption by losing as much weight as possible in every part of the vehicle while maintaining strength, toughness, impact resistance, chemical resistance, and other properties in replacement materials. Many of these plastics were on display recently at NPE2012 in Orlando, Fla.
Click on the image below to see these some of these solutions on display.
The smart forvision electric concept car co-developed by BASF and smart has several features that help it lose weight. One of the main ones, which BASF showed at NPE, is the polymer wheel rim made of its Ultramid Structure, with long reinforcing glass fibers, which saves up to 30 percent of the weight of a metal wheel rim. BASF representatives said this is the first polymer wheel rim that can be mass-produced. (Source: BASF)
Interesting slide show, Ann. It's pretty amazing what they can accomplish today via use of bioplastics and innovations in injection molding processes. It seems like a lot of the lightweighting work takes place in the dash system. It strikes me that there should be a lot of other opportunities, particularly in the frame, to take weight out of the vehicle makeup.
Thanks for sharing this. Lots of great possibilities here.
I think the dash is the easiest application but the last slide stel in the door panels was replaced. I wonder how lightweight plastics have been/will be used in motorcycle helmets? And, how long do they last? The moving parts are constantly used and safety is the main concern in such a small space.
Ann: I ride a motorcycle. My curiousity is around appllying the newer lightweight plastics to helmets. Helmets have gotten much lighter over the years but there is a perception that heavy equals safe. Lightweight componets have been introduced over the years but tend to break off and need replacement with intense use.
I worked in the motorcycle business for many years. Helmets have always been the trickiest thing to make. Plastic helmets have been manufactured, but the best, lightest helmets have always been fiberglass. The reason is that the plastic shells were actually too durable! Thin fiberglass can be talored to crush and abrade at specific rates. The shell actually is designed to crumple like the front and rear zones of modern cars. The newest plastics will probably be able to take over soon, but so far the best helmets are fiberglass construction.
You are correct that I said that the helmets require some controlled crush. Motorcycle helmets are intended to be a single use item. The shell is designed to prevent penetration of a sharp object but not to stop it cold. The thing is you can make a shell that stops just about anything, but if it transfers ALL the energy to the user you will pass along a concussion. Protecting humans is a tough job, and protecting humans HEADS is the toughest job of all. The helmets have a styrofoam inner shell that crushes to slow the energy transfer to your head. The Snell Memorial Foundation is a firm started to improve helmet safety. They have a series of design specs considered to be the best in the industry. Many racing organizations require the use of only Snell approved helmets. While I haven't checked lately, (7 or 8 years), to my knowledge no non fiberglass shell helmet has yet been Snell approved.
I think I get what you're saying, BillFZ1. The styrofoam absorbs some of the impact. Thus the impact is not all delivered to the head inside. I would imagine you run a risk of some objects benefiting from that construction and penetrating the helmet entirely. Apparently the greater risk is not allowing the styrofoam to take some of the impact.
You have the right idea. Plus, there is a safety comment written on the box every helmet comes in, "Caution! There are some impacts from which this helmet cannot protect you." Let's face it if you head on a Peterbilt tractor at 80 mph it doesn't matter what helmet you are wearing. Regarding penetrations Snell has a penetration test that uses a specific size ball end. If the rider runs into a spear point it won't matter. The compromise made by helmet manufacturers is the stuff that Lawers love to litigate. We were at a point where California, the largest motorcycle state in the USA almost could not get helmets at all. It is a fine line to walk between making a helmet that will absorb most impacts and one that is so large that the aerodynamic drag is so high that the rider can't use it for more than an hour. I commend the makers that are still willing to do it.
To return at least close to topic, I would love to see some of our new lightweight plastics used in helmets. perhaps as Chas mentioned molded with air spaces? The strength is already there, just a careful evaluation of characteristics is needed. Once a molded shell could be made to work correctly it would be able to be sold for much less that fiberglass or carbon fiber which requires a lot of hand work.
@Nadine- I have a keen interest in motorcycle and bike helmets as a rider of both and as an engineer. As others mentioned the best-performing motorcycle helmets use fiberglass, or lately Kevlar or carbon fiber for very high-end products. Polycarbonate is used for "budget" motorcycle helmets. They are heavier and there have been a few cases of splitting along mold lines in an impact.
You're correct that some of the new materials and processes in this article may shift the advantage back to plastics in helmets. (BTW, bicycle helmets are almost always a thin plastic shell with a thick polystyrene liner).
An aside- one big area for improvement is a truly "quiet" motorcycle helmet. The best helmets available still deliver 100+ db of wind noise at highway speeds, making earplugs a necessity. Most riders don't use earplugs...probably a source of regret in 10 years. (Mild tinnitus is my personal toll for not using them earlier)
Thanks, Beth. There are many opportunities to take weight out of the frame and structure via composites, but there are assembly and process issues involved with transferring those technologies to highly automated, high volume automobile manufacturing. Meanwhile, lightweight metals production for cars is also being studied and occasionally applied, though usually, like composites, to high end race cars and more customized apps.
This is great. Plastics (a variety of them) have been used in firearms frames for a while. That is a demanding application, and they last. The next step is to bring back aerodynamics. The trend toward SUVs and cross-overs (or station wagons, as they should be called) has hurt fuel economy at least as much as increased weight. I understand that most of the weight increase is the result of safety measures. Using plastics will help mitigate some of that.
naperlou, thanks for that input: plastic in firearms is a new one to me. That must be a very demanding application: heat, force/impact, etc. In automotive lightweighting, much of the materials design effort is to combine lighter weight composites and plastics with additional safety features.
Plastic has been user in firearms for decades - the Remington Nylon 66 was introduced in 1959 - but only recently in components other than stocks. Perhaps the best know weapon with a plastic stock is the M-16 of the Vietnam era. Now plastic frames, magazines, triggers and guards, and other components are routinely found in all types of firearms.
More on topic with the automotive direction of the blog, does anyone remember the Polymotor® from the mid to late 90's? As I recall most of the components, inluding the block and head, were made of plastic with metal inserts in high wear/high stress/high temperature areas. I believe the entire engine - it was a 2.0 liter 4 cylinder racing engine - weighed ~ 200 pounds.
BigDipper, thanks for that info: that's a lot longer than I would have guessed. It makes me think of the fact that composites have been used in aircraft for more than 30 years, and the applications are expanding.
I can understand how plastics will save weight in cars. However, I am concerned about a problem I am already running into with plastic parts in cars. I have an 2009 Toyota Matrix, and a 2010 Mazda5. Both of them use lots of plastic. In trim parts inside the car, and outside items like bumper covers that actually go up into the body. These parts use molded in plastic clips to attach the parts together and to the body. I have had a number of the clips break or come apart from normal use. My choices have been to either spend a fair amount of money to buy new parts or do what I can to come up with ways of using the parts on hand with my own solutions. So far I have chosen to fix them myself. While it works, it is not always the nincest looking result.
My fear is that with even more plastic in cars this problem will get worse. Will the car designers take this into account and come up with stronger and more reliable connections? Plastic headlight lenses save weight, but they loose clarity over time and must be polished in order to have a safe level of lighting.
@uniquity: That's a real reality check. It got me thinking about all the kids toys, small appliances, and other household items that now have injection molded parts that I have lying around my house in various states of disrepair or juryrigged to work. I certainly wouldn't want that to be the case for my car which costs me tens of thousands of dollars. That is a design issue that definitely needs to be addressed if this type of lightweighting produces cars that consumers (the non-fix-it types like me) are going to readily accept.
Uniquity, thanks for sharing your experience. That sounds like a fastener design/assembly problem, not a parts material problem: the durability, etc. of the plastic the clips are made of, and perhaps also their design, has not been properly matched to the characteristics of the plastic parts they fasten. Some fastener companies I've spoken to are developing new fasteners for these new plastic components.
Regarding plastic headlight covers, I saw some new plastics at NPE aimed at solving that problem.
I'd be concerned about using polycarbonate or PC/ABS for the hood of a tractor. These materials are known for poor environmental stress cracking resistance, especially when exposed to fuel or oil. Friends have told me about having this problem with other injection molded tractor hoods.
By the way, it seems like the images for slide 2 and slide 10 have been switched. Slide 2 shows a door module, but the text is about a tractor hood. Slide 10 shows a tractor, but the text is about a door module.
Thanks for that input, Dave. As the (correct) caption states, "The new formulation was developed to help overcome performance issues of fiberglass and metal, such as cracking or fading from exposure to high temperatures and ultraviolet light. SABIC's Lexan SLX resin is co-extruded over its Cycoloy resin and vacuum formed..." When talking to SABIC, they made it clear that they had worked closely with Apache to develop this material and overcome previous difficulties. The same goes for the white Volvo truck cab roof fairing made entirely from SABIC's Cycoloy polycarbonate/ABS resin, which they worked closely on with Volvo.
@Ann: Well, I'm not sure which metals SABIC is thinking of which crack or fade from exposure to high temperatures or ultraviolet light! (Certainly not if "high temperatures" are defined as temperatures which would be high for plastics).
As far as fiberglass is concerned, I don't doubt that PC and PC/ABS have better weatherability than a fiberglass-epoxy composite. But I think they are trading one problem for a potentially worse one. Fiberglass has excellent chemical resistance. With PC and PC/ABS, you now have to worry about splashing gas or oil on the hood of your tractor. (Not to mention pesticides and other chemicals).
An injection molded hood will be cheaper and lighter than a compression molded composite hood or a formed metal hood. But I'm very skeptical of SABIC's claim that the performance will be better.
PC and PC/ABS might look attractive compared to other injection molding resins because of their impact strength, but their chemical resistance is not very good. Better choices might be BASF's Terblend, or Ineos' Triax, both of which are nylon-ABS blends. (They used to be competing products, but since BASF and Ineos combined their styrenics divisions into one company called Styrolution, they're now both under the same roof).
The lightest parts are inflated parts with the internal pressure adding to get rigidity. Too bad space is such a premium on cars. Maybe the wheels and some structual body parts could benefit from this technology. (might add a softer collision factor in an accident)
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