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Kamesh Tata wrote:
=========================
>
> Bronson,
> Your response to resin stability question is very interesting. Would
you please take a few minutes to answer the following question.
>
> Since an increase in viscosity is the primary factor affecting build
> quality, can we increase resin temperature to bring viscosity down? If
> yes, how far can we go from resin manufacturer's recommended max.
> temperature? Any side effects?
...
> Kamesh Tata
G. Allen Brady Wrote:
===============================
> I'd like a swipe at this.
>
> Viscosity as a function of Temperature goes according to:
> Viscosity(Temp) = A*exp(B/Temp)
> where A and B are some constants.
>
> However, increasing the temperature will tend to increase the rate of
> the "dark reaction" polymerization. However, the rate of
> polymerization
> as a function of temperature is much more complex and will depend on if
> the reaction is diffusion limited (which I doubt). If not, then I'm
> sure the DuPont and/or Ciba folks have run some tests to explore this.
> Hey, this sounds like someone's Ph.D. thesis....anyone want to own up?
> Thomas?
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Response from the DuPont Somos Materials Group:
G. Allen Brady's assumption is correct. Therefore epoxy materials should
be used in the temperature range recommended by the manufacturer. To do
otherwise will likely accelerate aging, causing the resin to fail
prematurely.
Regards,
Bronson
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Bronson R. Hokuf USMail: DuPont Company
DuPont Company 2 Penn's Way, Suite 401
Advanced Material Systems (P&IP) New Castle, DE 19720
Somos(tm) Solid Imaging Materials Tel: 302-328-5635
E-Mail: hokufbr@esvax.dnet.dupont.com Fax: 302-328-5693
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