Talk Composites - The Forum for Advanced Composites

infusion through a 2 piece alum mould

http://www.talkcomposites.com/Topic21763.aspx

By jellyfishboards - 8/7/2016 10:05:14 PM

I have cnc a 2 piece alum mould and would like to do infusion through it...  the part is  900mm long x 120mm x11 mm and will have 3 different kinds of carbon in it.   Is it possible to pull through it 
I have cnc a place for a gasket around the rim of the mould ,  put placement for inlet port and outlet port. 



the way I have been doing it is a wet prepreg hand lay into moulds  putting the two pieces together and pressing it in my heated press.  Finish isn't there and needs too much hand work in the end. 

so my goal is to do a dry lay up in the alum moulds   put them together , put them in the press under 5ton of pressure , pull resin ,  bump the press up to 40 ton and hit it with heat to cure the resin.  
I am using heat cured resin  so the parts will not deform in the sun on the beach.   Resin cures  in I hr at 180 degrees. 

any advice would be great...

thank in advance
terrie
By Fasta - 8/25/2016 2:19:57 AM

Will.Harris (24/08/2016)
Fasta (19/08/2016)
I don't imagine that applying 5 ton pressure will help with infusion. For infusion you need some degree of pathways for the resin to flow and move. Once you apply any significant pressure then there is no way the resin can move through the fibres.

This isn't strictly true - with RTM, the cavity is fully defined by two closed mould surfaces.  Assuming the top half of the mould doesn't deform under 5 tonnes of closing force, then the fibre stack can't be over compressed, and permeability shouldn't be an issue...as long as you have done your calculations correctly, and don't have too much fibre in the cavity in the first place!

Have you considered injecting under positive pressure?

I am working on a commercial project developing RTM injection of windsurf fins/foils. Sadly its hugely covered by NDAs, so cant share too much info, but I can say that what you are trying to achieve is definitely possible!


RTM is with positive pressure isnt it?

We are talking about vacuum infusion so far.

In some recent samples I have done there was a thicker section of laminate sample with 10 layers of 450g uni carbon and the resin front near stopped in comparison to the rest of the laminate. So resin did not really flow and this just a regular vacuum bag job, about 14psi pressure. 

Uni fibres really nest/stack very well leaving almost no pathway for resin flow.

I think jelly could try just filling the moulds with the carbon but do not over fill the moulds to avoid the pressure on the fibre stack. Then use the press he has to clamp the moulds and then infuse. This way the press holds the moulds really solid yet there is no significant pressure on the fibre and letting the resin move easier. The foil will still have heaps of fibre in it and be very stiff.