Design a Manufacturing Process for Carbon Fiber Car Hood

[AlphaFloor]

Hello all,

As a part of my intership in a CFRP (carbon fibre reinforced polymer) manufacturing company I have to come up with a process definition to produce a car hood (the hood consists of a skin and an inner reinforcing structure). The process has to deliver 10.000 CFRP hoods a year and my task is to explain how that will be done. Also I have to estimate material consumption, costs and cycle times.

The problem is, I'm an aerospace engineering student and know very little about composites and manufacturing processes, yet alone about designing one. So I don't really know how to attack the problem. I've been told that this should be very easy and that this is basic know-how of any engineer... well I don't think so.

So far I have thought about an RTM process with the following steps:
Cloth cutting -> creation of a preform -> placing preform into steel mold -> mold closure and seal -> placing mold in RTM injection press -> resin injection -> cure under heat -> removing mold from press -> demolding the part -> adhesive bonding with reinforcing structure -> trimming -> quality control ... After demolding the part the mold has to be prepared for the next part, cleaning and release agent etc.

But thousands of questions arise all the time and I feel pretty lost. How do I design the mold itself? How do I heat the mold and how long does it take? What's the energy consumption? How do I move the steel mold around the shop, do I need a bridge crane? How do I guarantee that every produced part is interchangeable? How do I define process robustness? How many workers do I need? On top of all that: how do I estimate the cost of all individual steps and of the global process?

My question to you is not so much how to solve my problem, but where can I learn about designing a manufacturing process so that I can do it myself. Any books, websites, videos or resources of any kind will be welcomed!

Thanks

 

[Compositepro]

Look on you-tube to see BMW's process.

 

[ornerynorsk]

If the company that you're interning at is already in the business of manufacturing such articles, then you've got people who can help you find the answers. A little observation and small talk as to who does what in the company, which of the highly skilled people have been there the longest, etc, might yield a goldmine of exactly the information you are seeking. A little time spent befriending such people, bringing coffee or rolls once in awhile, you get the idea.

Also, what is the timeframe of your project? As they say, almost anywhere is walking distance if you have enough time.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[TVP]

It sounds like you need to spend some time in the library. There should be many references that you can review related to composite manufacturing. RTM is one process that many people in the industry have evaluated, and continue to evaluate, for relatively low cost automotive manufacturing. Here are two recent books published by SAE that you should check to see:

Design of Automotive Composites

http://books.sae.org/pt-164/

Automotive Carbon Fiber Composites: From Evolution to Implementation

http://books.sae.org/t-124/

 

[tomwalz]

Car hood plans are common starter projects for learning carbon fiber work.

Bringing doughnuts to old guys is always a good idea.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.