WE CLAIMED:
1. A method for producing blow molding instructions for a bottle preform, the method
comprising:
creating a first set of blow molding experiments for blow molding a selected
preform design into a target bottle design, each experiment having a different set of blow
molding parameters;
simulating each experiment of the first set of blow molding experiments using a
simulation software program;
selecting a group of experiments from the first set of blow molding experiments
based on downselection criteria,
wherein the downselection criteria comprises:
a wall thickness of a simulated blown bottle,
a section weight of the simulated blown bottle, and
an elastic modulus × wall thickness value of the simulated blown bottle;
creating a second set of blow molding experiments based on characteristics of the
downselected group of first experiments;
simulating each experiment of the second set of blow molding experiments using
the simulation software program;
selecting an experiment from the second set of blow molding experiments based
on characteristics of the selected experiment’s simulated preform and simulated blown
bottle,
wherein the characteristics of the selected experiment’s simulated preform and
simulated blown bottle include preform weight, simulated bottle wall thickness, and
breadth of process window; and
producing blow molding instructions based on the selected experiment.
2. The method of claim 1, wherein the characteristics of the selected experiment’s simulated
preform and simulated blown bottle comprise simulated preform weight and simulated
bottle wall thickness.
3. The method of claim 2, wherein selecting an experiment from the second blow molding
experiments is also based on a breadth of process window for producing the simulated
blown bottle from the simulated preform.
4. The method of claim 1, wherein selecting the group of experiments from the first set of
blow molding experiments comprises:
comparing wall thickness values of the first set of experiments to an acceptable
range for wall thickness to identify a first qualifying set of experiments;
comparing section weight values of the first qualifying set of experiments to an
acceptable range for section weight to identify a second qualifying set of experiments;
and
comparing elastic modulus × wall thickness values of the second qualifying set of
experiments to an acceptable range for elastic modulus × wall thickness to identify a third
qualifying set of experiments, and
wherein the third qualifying set of experiments is the group of experiments.
5. The method of claim 4, wherein the acceptable range for wall thickness is a minimum
wall thickness determined from target thermal stability data and permeation data for a
finished bottle.
6. The method of claim 4, wherein the acceptable range for section weight is a minimum
section weight determined from pressurization data for a finished bottle.
7. The method of claim 4, wherein comparing wall thickness values comprises comparing
wall thickness values at multiple areas of each simulated bottle, and wherein the
acceptable range for wall thickness is different for each area, and
wherein comparing section weight values comprises comparing section weight
values for multiple sections of each simulated bottle, and wherein the acceptable range for
section weight is different for each section.
8. The method of claim 1, wherein the blow molding parameters comprise:
preblow pressure;
melt flow rate;
stretch rod speed;
preblow timing; and
temperature distribution.
9. The method of claim 8, wherein preblow pressure, melt flow rate, and stretch rod speed
are the same for all of the first of blow molding experiments, and
wherein preblow timing and temperature distribution are different for at least
some of the first blow molding experiments.
10. The method of claim 1, wherein the experiment selected from the second plurality of
blow molding experiments is associated with a blow molding recipe having a broad
process window.