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.
Thank you for your suggestions and opinions.