Experiments were run under normal machine settings and with variations in blow pressure
One way to accentuate the difference in sand flowability is to lower the blow pressure
in 10-psi increments, make cores and then weigh them at each blow pressure
Cores are blown by an advanced blowing system with lower blow pressure
, backed by a long list of successful references.
Mixed Sand Quality Tests - Once per shift, foundries should test for loss on ignition, and blown tensiles (specific blow pressure
and gassing times and specific curing time between gassing and break) should be spaced over the use life of the sand.
The authors (17) also studied the effect of ISBM process parameters and preform design on the bottle properties; the process parameters comprising the blow pressure
, the timing of the blow pressure
activation relative to the stretch rod motion was studied to improve the simulation predictions of bottle wall thickness (18), (19).
The optimal conditions are rear temperature of 320 (degrees)F, front temperature of 300 (degrees)F, block temperature of 300 (degrees)F, injection pressure of 1000 psi, blow pressure
of 60 psi, mold temperature of 120 (degrees)F, and mold close time of 60 seconds.
depending on the processing conditions, such as blow pressure
, melt temperature, mold temperature, etc.
and humidity had only a small effect on shrinkage.
Some newer developments include improved infrared heating techniques for reheat blow molding; very high speed rotary extrusion presses, particularly for the milk container industry; mold indexing on shuttle presses to allow for offset spout formation; multilayer continuous extrusion blow molding for barrier containers; and the continuous production of heat-set PET bottles by carefully controlling orientation crystallization and thermal crystallization, preform and mold temperature, and blow pressure
and residence time in the mold.
utilized is a function of part size and parison wall thickness.
Engineers have hooked up compressors to conduct cooling and blow pressure
When the rod reaches the bottom wall of the container, a high blow pressure
is applied inside the preform to reach the final container shape and maximize cooling efficiency.