[vcx]

Hi, I'm not sure the process of thermoset composite.

As i know thermoset and composite reinforced with short and continuous fibre  is better using compression moulding compared to injection moulding.Is it due to thermoset harden, and this process also have to undergo  heating and cooling while processing before final finish article obtained. Why its need to do so? or am i have the wrong idea? 

And for  thermoplastic it is better use injection moulding campared to compression moulding. Is it due to its reversible soften by heating and harden by cooling properties? Can thermoset composite processed by using injection moulding? or is it any limition to do so, other than its irreversible property?

Thank you.

[eugenedakin]

Hello vcx,

I dont believe that compression moulding vs injection moulding changes the properteis bue to the hardening process.  I believe that compression moulding increases the density and forces the short and continuous fibres closer together... thus, incresing the strength.. along with increasing the amount of material (and fibres) in the material.

Hmm.. I am not sure which is 'better', as it is a relative term.  The final product (and your process equipment, efficiency, etc.) will determine the 'best' use and process...

I hope this helps,

Eugene

[Yafmot]

    The processing of composites is far too broad a subject to run down on a forum post. As far as injection molding of thermosets goes, it's pretty tough to get right. Technically, it's called Reaction Injection Molding (RIM).

    The difference is that, with thermoplastics, as long as you keep the temperature of the material high enough, you can take all the time you want. But with thermosets, once that catalist is mixed in, the clock is ticking, and if the stuff "goes off" in the pump, lines or runners, you've got a real mess on your hands, with a good 2 weeks downtime.

    Check with some of the thermoset manufacturers. Most would be happy to send you in the right direction as to papers, monographs etc.