Patent ID: 7092855

Claim:
A method of structuring a thermally stable coating die apparatus having a Z-dimension die width distance to X-dimension die distance and/or Z-dimension die width distance to Y-dimension die distance ratio greater than 2.5 and a steady state operating temperature, the die apparatus including a die having a die geometry including die lip faces in Y-Z planes and a slot opening perpendicular to the lip faces in an X-Z plane, active heat transfer means, temperature and/or heat flux sensors, to provide flat die lip faces under die operating conditions, the method comprising: maintaining a nominal state of bending flatness of the die lip faces in the X-Z plane to less than a defined flatness deviation and not changing the magnitude of die lip flatness deviation in the X-Z plane or Y-Z planes more than a defined flatness deviation when coating commences, while balancing the heating system to minimize temperature gradients in the X-Z plane and/or Y-Z planes for a predictable amount and direction of bending in the respective plane, using one or more of die geometry, placement of the active heat transfer means, placement of temperature or heat flux sensors, shielding from operating conditions, heat transfer and structural numerical modeling, statistical analysis, temperature or heat flux, dimensional, strain and/or stress measurement techniques, die functionality, minimum increment of temperature measurement and control accuracy related to minimum acceptable deviation from flatness, coating die material of construction relative to thermo-structural material properties, and desirable coating die material properties.