Thanks for replies so far. My concern is 'filling' the mould, regardless or whether you use pre-preg or an infusion process, to prevent a part with excess resin you need to ensure you have the cavity 'full' of CF - easier said than done! Any suggestions on that front?

Re: reply by VVF, I too used to work in injection moulding, admittedly as a design engineer not as a machine setter but that is the first I've heard of 'exit ports' on a mould tool. Usually a 'shot' of plastic is injected and a holding pressure is then maintained as the part cool and shrinks, it is this holding pressure which helps ensure the part conforms to the mould cavity with less shrinkage and warpage, at least that is my understanding, maybe there are different ways of doing things. Of course I'm talking about regular injection moulding too, not compression moulding.

@ fgayford ..

I'll try to dig out the few photos I have of the process .. the mould now resides on another island, and even if my country is small, its still a bit of a drive to get there (across 3 bridges, one of which is the worlds 2. longest suspension bridge .. )
I'll try to get my friend to email me a few photos ...

I do have a few much simpler alu moulds, that work the same way .. I'll dig them out and do a test run .. with a few pictures along the way --

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

I am pretty sure those head support parts are hollow since I looked at repairing one a while ago.

Hi Dravis
I sure would be interested in seeing some pictures of the whole process.
Thanks
Fred

I have made rifle-scope mounts by having an aluminium mould CNC milled.  The thickest parts of this mount are 18 mm of "solid Carbon fibre"

This mould is water/oil heated ..  I planned for the use of prepreg, but started out using infusion .. so I have a number of very small "extraction holes" and three "injection holes in the mould .. it worked so well that I have now sold it to a friend who is starting up a company that produces CF parts for firearms ..

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

I work for a company that use injection moulding and the moulds still have exit ports for any excess plastic to exit from, they actually exhaust a small amount everytime you inject because of shrinkage when the part has cooled,




so you would apply similar practice if making carbon,

you would have to do some set up runs to get your loading right and then once right simply make parts.

Nobody know how something like this is moulded?

http://www.lotusclubqueensland.com/images/stories/hans.jpg

Hi, new here.

Only done a couple of simple carbon parts before but have a slightly more ambitious project in mind which I don't know how best to approach. How would you set about making a fairly thick section solid carbon part - think something like HANS device (don't worry I'm not attempting to make my own HANS!).

I understand the principles of vacuum bagging but if you have a split enclosed mould (like an injection mould tool), how would you ensure complete fill, create the pressure and where would you evacuate any excess resin (assuming pre-preg)?

I guess the tool would want to be aluminium and heated so as not to take too long to come up to temp in an oven?

Thanks for your assistance.