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Pressure at End of Packing
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Shows the pressure at
various part locations at the end of the packing phase. At the end
of packing, most of the part is expected to have near zero pressure.
The presence of zero pressure combined with locations with
small pressure range (min/max value) is a good indicator of an
effective packing stage.
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Temperature at End of
Packing
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Provides a snapshot of
the temperature across the part at the end of the packing phase. The
outside region (skin) has a much cooler temperature (blue color), as
it is in contact with the cooler mold surface. Use the
clipping plane to look for high temperature regions through the
thickness (red color).
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Bulk Temperature at End of
Packing
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The bulk temperature plot
indicates where material has cooled down to the mold temperature
(blue), and where material is still molten (red or yellow). The
changes in melt temperature during the packing stage are calculated
from parameters such as time, mold temperature, and part wall
thickness. |
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Density at End of
Packing
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The Density at End of Packing
plot can determine how effectively a part has been packed. Similar
to the Pressure at End of Packing plot, the
Density at End of Packing plot should
ideally be uniform throughout the part. Variations in density lead
to potential problems in non-uniform shrinkage and warpage. Areas
with low density are also susceptible to void formation. |
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Shear Stress at End of
Packing |
Shear stress is a measure of the shear force the
plastic material is undergoing within the cavity. Certain materials
are very shear sensitive, and therefore simulation can be useful to
gauge whether the shear stress exceeds the material’s recommended
maximum shear stress (this value can be found in the material
properties). Excessive shear stress can degrade the material
and cause visual defects, which are undesirable especially for
aesthetic parts.
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Shear Rate at End of
Packing |
Similar to shear rate, this result can be used to gauge
whether the shear rate for your design exceeds the material’s
maximum shear rate. |
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Volumetric Shrinkage at End of
Packing |
All plastic materials are compressible
and,therefore, experience shrinkage in volume as they go through a
phase change from liquid (filling stage) to solid (packing/cooling
stages). High rates of shrinkage occur in areas of the plastic part
that do not undergo sufficient packing stage. Uniform shrinkage
throughout the part is desirable. If the range of the
volumetric shrinkage is relatively high for your design,
attention should be given to part design (uniform thicknesses
are desirable) and mold design (packing pressure/time, gate
size, number of gates, and gate proximity to high shrinkage
areas).
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Temperature at Post-Filling
End |
The Temperature at Post-Filling
End plot is based on when 90% of the part volume is
below the material deflection temperature under flexural load, the
ejection temperature. If there is a large temperature distribution
in thick regions of the part, several problems may occur such as:
sink marks, internal voids, or warpage. To reduce these problems,
you should design the part with a uniform wall thickness. |
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Freezing Time at Post-Filling
End |
The Freezing Time plot indicates the time it takes for
the plastic material to cool down to its transition temperature. The
freezing time depends on the temperature differential between the
melt temperature and the mold temperature, and on the thermal
conductivity between the melt and mold. For
solid meshes, use the Clipping Plane mode
to view the freezing time of elements at the
interior.
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Residual Stress at Post-Filling
End |
During the injection molding process, the polymer
is exposed to thermal and physical stresses. Residual stresses are
forces locked within the polymer as it cools from the molten state
through the glass transition temperature. The residual stresses are
a result of the non-uniform cooling and pressure variations that
occur in the viscoelastic polymer material during molding. A
part with high levels of residual stresses might fracture, or it
might undergo other physical changes after molding such as
warpage.
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Frozen Area at Post-Filling
End |
The green areas of the plot represent areas that have
frozen solid (temperature is below the material’s glass transition
temperature). The red areas of the plot are still above the glass
transition temperature at the end of the post-filling (just when the
part is ready to be ejected from the mold). Ideally, there should be none to very small areas of red color.
Use the clipping plane to view the part interior through its
thickness.
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