Improved Composites Manufacturing

JoeSilva writes: "I immediately thought this cheaper and faster process for manufacturing composite materials could really lend a hand to the goals of HyperCars a-la the Rock Mountain Institute folks, and Reusable Space Launchers a-la X-33/VentureStar, Roton, and others. The RMI folks have been advocating use of carbon fiber composites, but have noted that Aluminum has seen some favor with the Auto manufacturers, and one reason for that has been cost. The X-33 program was set way back due to a manufacturing failure in making what they claimed was the worlds largest carbon fiber composite fuel tank...in fact I recall reading that there was no AutoClave in the world big enough for the tank size for VentureStar. The X-33 was a smaller scale test vehicle...not a launcher. The new process can make whole boats and airplane fuselages."

Correct Hypercar link

[Bearpaw]

I think you mean Hypercar [hypercar.com].

Re:Auto manufacturers won't use this...

[thomis]

Ahh...Injection-molding. I don't understand how you could do composites with that, but then, I'm not a fab expert, just excited by the idea of cheap composite manufacturing. Obviously, this stuff is a bit beyond building a canoe 8~). I think that the vibration/(relatively)low-pressure combination is a plausible way to address those kinds of defects. With carbon-fiber, that frees you worry about strand orientation and resin schtuff. The Really Cool Thing here, I think, is that this might be within the realm of the garage workshop. I would looove to fab my own composites (that don't de-laminate when looked at wrong)!

Re:Auto manufacturers won't use this...

[thomis]

... Because they don't read the article before commenting either. From the article:

Dr Hodgkin, says that the Quickstep process is a fast fabrication method for making very high quality (to aerospace standard) composite products without using an autoclave. ... The process has superior performance to autoclave, vacuum and atmospheric curing methods in terms of strength, stiffness and appearance." I appreciate that you have an understanding of the topic, due to the detailed nature of your comment, but I almost skipped the article after reading what you had to say. But, apparently,

The vaccuum used in an autoclave is necessary to 'suck' out airpockets

is actually 60-200 psi. As far as the recycling thing goes, you may have a point. But, as far as I can tell, recycling technologies are usually developed after a manufacturing technology.

Re:Auto manufacturers won't use this...

[grammar nazi]

I assure you that I did read the article before commenting. I disagree with what he said regarding the autoclave, that's all.

Most of what I mentioned comes from experience comparing nylon thermoset casting processes with injection molding techniques. The process described in the article sounds like a very similar comparison, except with an autoclave instead of an injection die.

The autoclave uses a vaccuum to remove airpockets in much the same way that injection molding uses high pressure to 'push-out' air-pockets. I based my opinion on that assumption. Of course it may be wrong. Thanks for pointing that out. I'm going to look into it in further detail and see what I can figure out.

Auto manufacturers won't use this...

[grammar nazi]

Hi.

The main reason that the Automobile industry will never use this is the same reason that it hasn't gone anywhere with ceramic engines. In the early '80s, the big three auto companies did research on Ceramic engines that could run hotter and were lighter and stronger than steel engine blocks. The reason that the development never went anywhere had nothing to do with ceramics' brittle nature (which is just a design technicallity). The reason was because ceramic engines couldn't be recycled. Towards the middle of the '80s, recycling automobiles became a big deal and it has been ever since.

Carbon fiber paneling won't ever replace aluminum because

Aluminum is Earth's most abundant metal

Aluminum is infinitely more recycleable than carbon fiber composites. The only thing that you can recycle carbon fiber composites into is chopped-carbon fiber composites.

The process from the article is useful for a couple of things. Large carbon fiber shapes can be created because an autoclave is no longer neccessary. Protype carbon fiber components can be created because of no autoclave and cheap molds can be used.

I don't feel that high quality carbon fiber components will ever be created by this process. The vaccuum used in an autoclave is necessary to 'suck' out airpockets and provide a uniformly dense material. The carbon fibers are brittle and the stress concentrations that arrise in microscopic air pockets are enough to fracture the fibers (eventually). This same problem has occured over and over again in other thermoset composite processing techniques (what the article describes). I worked on a thermoset production process for Glass Fiber enhanced Nylon.

These techniques are innovative and they have important applications. However, these applications are limited to low-cost and low-quality components, or components where the traditional processes can't be used (complex geometry components, or, large/small scale components).

Roton

[maddogsparky]

Is Rotary Rocket still alive? I don't think their website has changed since their CFO became their "acting" CEO many months ago (except for removing any email contact info, that is). If anyone knows otherwise, please reply.

Venturestar, et al..

[RapaNui]

As far as the fuel tank issue goes, aren't most tanks (as in propellant, etc.)
filament wound? In which case they don't *strictly* need
an autoclave (except maybe for some level of debulking),
they mainly need some sort of curing oven.

If this new system works with existing resin systems and prepregs
(esp. for low-cost mass production parts) it will be quite something.
The only thing that bothers me is with the *extremely* rapid cure, what
happens to thermal and dimensional stability of the parts compared with a long
ramp-up/ramp-down cure cycle?