Method for designing a profile extrusion die plate

A method for designing a profile extrusion die for shaping a resin, the method comprising the steps of:

• providing a representation of the resin shaped by a die, the representation illustrating a relationship between die swell of the resin, shear rate of the resin through the die, and the ratio of die land length of the die to die opening thickness of the die;
• determining from the representation instances where the ratio of die land length to die opening thickness minimizes die swell of the resin, the die swell of the product leveling off as the ratio of die land length to die opening thickness increases;
• obtaining experimental data of the resin shaped by an experimental die, the experimental data including draw speed, shear rate, and die swell;
• arranging the representation and the experimental data into a die design chart for die opening thickness and die opening width, the design chart for die opening thickness containing representations of draw speed, a thickness factor, and shear rate, the design chart for die opening width containing representations of draw speed, a width factor, and shear rate;
• and
• using the die design charts to determine dimensions for a desired profile extrusion die.

A method for designing a profile extrusion die for shaping a resin product, the method comprising the steps of:

• providing a representation of the resin shaped by a die, the representation illustrating a relationship between die swell of the resin, shear rate of the resin through the die, and the ratio of die land length of the die to die opening thickness of the die;
• determining from the representation instances where the ratio of die land length to die opening thickness minimizes die swell of the resin, the die swell of the product leveling off as the ratio of die land length to die opening thickness increases;
• obtaining experimental data of the resin shaped by an experimental die, the experimental data including draw speed, shear rate, and die swell;
• arranging the representation and the experimental data into a die design chart for die opening thickness and die opening width, the design chart for die opening thickness containing representations of draw speed, a thickness factor, and shear rate, the design chart for die opening width containing representations of draw speed, a width factor, and shear rate, wherein the representation in the die design charts are a plurality of shear rate curves;
• implementing the die design charts into a memory of a processor;
• and
• using the die design chart in the processor memory to determine profile dimensions of a desired profile extrusion die.

An article of manufacture, comprising:

• a computer usable medium containing computer readable program code means embodied therein for designing a profile extrusion die for a profile, the computer readable program code means in said article of manufacture comprising:
• first computer readable program code means for dividing the profile into a plurality of sections;
• second computer readable program code means for setting initial die thickness and width to the final dimensions of the profile;
• third computer readable program code means for setting the draw speed for the profile;
• fourth computer readable program code means for determining the shear rate for the profile;
• fifth computer readable program code means for reading design charts stored in a memory to obtain a thickness and width factor for the corresponding draw speed and shear rate;
• sixth computer readable program code means for determining the final product thickness and width from the thickness and width factors;
• and
• seventh computer readable program code means for repeating the steps of setting die thickness and width, setting draw speed, determining shear rate, reading the design charts, and determining final product thickness and width, until values converge.