twintex cures without bagging

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#1

OK i have a biggish job starting next month and it requires twintex materials and Im looking at ways to reduce production time…

I had a bit of an idea that may work but havent tried yet and thought id see if anyone has had experience with twintex processes.

As it requires 190-210 degrees to melt the plastic and relatively low pressures I was thinking maybe I could autoclave without bagging, could i get a decent finish? I think i may have to tweak the cycle program so the pressure ramps up before the heat much quicker than if i was curing carbon but if the pressure (im thinking around 7 bar) was applied to squeeze the material into the mould before it melts then it should eliminate the risk of the material peeling off the mould. I would also use an adhesive that melts at 190 mark.

I will trial next week but any thoughts would be appreciated :slight_smile:

#2

How did you have material squeeze without using a bag? no idea

#3

Hi ovikas,

I havent tested the theory yet but i have spoken to a material manufacturer who has achieved it and I wanted to see if anyone has had any thoughts. Im hoping the clave pressure will hold the material against the tool and with bond materials holding material in place to stop movement. If we could do this and bypass bagging it will make for fast processing

#4

If you are trying to reduce cycle times try a reusable bag. If you want to make a quality, void-free part you need to bag it.

#5

If you not using bag, then does not make sense to apply pressure, because you will not have a differential pressure that will squeeze your plies together.

#6

Hi Everyone.

I thought if pressure was applied it atmospheric conditions it would work… I know it wouldnt work well with resin based systems but i thought it could work with plastic based materials.

I have spoken to twintex supplier today and they think it will work but more i think about it, the more i think reusable bag might be the only way to speed up production…or press tooling.

#7

Yeah…if Twintex is a fabric…how would any pressure without a bag do anything? Pressure will be, well…everywhere. There is nothing to push the fabric into the mold. NO, just bag it. It’s a prepreg fabric, the only way to do it is bag, or pressure mold.
The pressure from the autoclave will just surround the fabric and the mold. It will just sit there like it was out of the autoclave in an oven. No difference. The bag and the vacuum/vent to ATM in the autclave is what creates the pressure differential, that presses the bag into the mold.

#8

Thanks for your input Riff42,

Ive found reusable silicone bags that have an air tight zip system so il just use that. its an envelope bag. saves wasting time and trialing things that probably wont work…