Tech question for srinkage on carbon part


Tech question for srinkage on carbon part
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RTM
RTM
RTM
posted 9 Years Ago HOT
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Evening Chaps,



I have a technical question that I can't seem to work out what is causing my problem on carbon piece I'm making at the moment.

The part I'm making is a shroud protector for hovercraft fan. Its made up of 8 identical parts the will have joiners in-between to make a full circle when finished. So the part is a 1/8 of a circle arch that is hollow tube.

I have my mould and I'm using pre preg carbon with a bladder insert as the shape is cylindrical and hollow.

Currently curing at 25Degrees for 8hours and with the bladder at around 14psi.

The problem I'm getting after pulling the part is that is doesn't natural go back into the mould and rest. Seems to have flexed or pulled in or shrunk I'm not to sure for the technical term for it.

So my question what can cause this, i wonder if when curing my mould could have moved with the heat. But I can't seem to work out what might have caused this issue. 

I have attached some photos that can hopefully better show you what I'm describing.

Regards

Chris
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Fasta
Fasta
Fasta
posted 9 Years Ago HOT
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14 psi is not much pressure but the bladder process does rely completely on the stiffness of the mould. So maybe it could be the mould bending? I recently had the same problem with a fan blade we made but this was 40psi.

With a vacuum bag process there is far less reliance on mould stiffness.

I also recently made two large 3m dia hovercraft shrouds for a 17m craft. These were made by vacuum infusion process.
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Tech question for srinkage on carbon part
RTM - 9 Years Ago
     curved components will always move about depending on your layup, have you gone quasi layup in your...
scottracing - 9 Years Ago
     Thanks for the reply, Yes part is given plenty of time to get back to ambient temperature and then...
RTM - 9 Years Ago
     If you are only using a single ply it will be difficult to counteract the spring action without...
scottracing - 9 Years Ago
     Just the EC pre pre twill at the moment, but if there is a better material or number of layers or...
RTM - 9 Years Ago
     14 psi is not much pressure but the bladder process does rely completely on the stiffness of the...
Fasta - 9 Years Ago

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