An exploration into low cost and quick carbon mold production

We would like to make a full sus carbon fiber mountain bike in the Spring of 2023, but we are nervous about attempting the traditional carbon mold methods. They are expensive, difficult, and heavy. All things that are ok if you’re using the frame hundreds of time. However, we only want to make ONE bike frame to test our design and geometry.

Our president (Ziven Posner) had the idea to 3d print a bike and wrap it in carbon fiber, then stick it in a vacuum bag to cure. It was a great idea, but then we would be left with a ton of plastic adding weight but not stiffness or strength. To get around that, he suggested using water soluble filament. This way, we could dissolve the plastic after the carbon cures.

It would allow us to design and fabricate a super custom frame for a relatively low budget. The only issue was, would it work?

That’s when we decided to test it! The headtube area has a lot of compound curves, so we decided to try our method with just the headtube.

After modeling it, we 3d printed it
The print turned out well, for the most part
After the carbon cured, we soaked it in the sink and trimmed of the excess carbon
It was slow going, but after a few days was all cleared out
We did a float coat to clean up the exterior!
The final product!

All in all, we are very happy with the results. Squeezing it is surprising because of how stiff it is even though it weighs almost nothing. To be clear, we didn’t to any FEA or testing. This whole little experiment was simply to test a new manufacturing method to check for any blind spots and gain some intuition with the process.

I hope you enjoyed, and stay tuned for more research into carbon fiber manufacturing methods!

Categories: Engineering

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