Re: Finite Element Solution to 1D Polymer Film Problem

[EMAIL PROTECTED] (Drago) wrote in message news:<[EMAIL PROTECTED]>...
> Greetings!
> I am having a hard time finding heat transfer coefficients (k) for
> various polymers (nylon, polyester, polyethylene). Would anybody know
> an online source?
> 
> I am trying to perform finite element methods to determine the
> required seal times at various temperatures on packaging lines. Has
> anybody perfomed this type of calculation before or know of an
> available calculator/program?
> 
> Generally, packaging machines have dwell times of approximately 0.4+
> seconds with sealer bar temperatures of 170-175 deg C. The sealing
> material, generally polyethylene in this case, requires to be raised
> to approximately 140-145 deg C in order to achieve an even seal. The
> back side sealer bar is normally kept at room temperature, or slightly
> above. The pressure applied to the sealer bar can vary, but it is
> assumed that full contact is made between the sealer bar and the
> polymer film and that the surface of the film reaches the sealer bar
> temperature immediately.

Adhesion takes place at such a small scale that you cannot model it
with your approach, you need a molecular approach, and even that won't
be easy (trust me, I worked at 3M for 11 years). In addition, you have
a phase change that is dominated by kinetics (i.e., Tx is not equal to
Tm).

How did you manage to get a supercomputer account? ;)

John