The longer parisons
change the positions of important program points and the result can be containers that are out of specification.
4 was identified to be too simplistic, due to the complex shape of the extruded parisons
created by VWDS/PWDS die gap manipulations.
Options: IML, remote wireless diagnostics, remote parison
adjustment, turnkey systems.
In the extrusion blow molding process, the first step in the molding cycle is the parison
Skov says new techniques address the inherent difficulties of"changing a hollow, round parison
into a thin, flat, rectangular shape.
A "reverse" barrel temperature profile is preferred for extruding parisons
However, no published literature has dealt, in detail, with the swelling and sagging behavior of LGF reinforced parisons
In Milacron's new control strategy, now standard on all of the company's multi-head machines, push-out velocities are continually adjusted to keep all the parisons
It is well known that parisons
are considered as incompressible hyperelastic or viscoelastic isotropic membranes; therefore, the theoretical work of Green and Adkins  on the inflation of rubber membranes is commonly used as the basis of such studies.
Although there have been attempts to continuously extrude very thick, large-diameter parisons
for the several minutes needed to cool the part in the mold, the preferred method is to accumulate the melt in a vessel ahead of the extrusion screw, and then extrude the parison
at a relatively high rate to ensure minimum variation in parison
wall thickness owing to sag and extrudate swell.
For the programmer to work properly, it is very important that the length of the parison
be always the same, and that all parisons
in a multi-cavity setup have the same length.
Ryan and Dutta  observed the parison
free inflation and reported that longer parisons
inflate more uniformly in comparison to shorter ones owing to the end effect's becoming less significant.