EFFECTS OF EXTRUSION BLOW MOLDING INTERNAL COOLING ...

3.3 Compression Strength
Compression strength tests performed on the finished containers revealed very
little difference between processes. In both cases, failure was seen in the heel
area resulting in buckling of the bottle walls. Table 9 shows a comparison of the
compression test results for conventional versus Fasti containers. The p-values
in the table are less than 0.01 in each category showing that the data is
statistically significant. The statistical significance however, does not speak of
the practical significance of the effect the Fasti system has on the container. The
higher crushing yield load of the Fasti container is likely attributed to the slightly
higher average thickness of the container at the crush failure point displayed in
the data in Appendix A.
Table 8 shows significant data difference in the apparent crushing stiffness of the
containers to theorize that the Fasti containers may have a lower percent
crystallinity and therefore lower stiffness as expressed in Table 9. This theory
was tested in Section 3.4. All compression strength data is displayed in
Appendix B.
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