Die Ovalization

The parison material thickness also changes vertically (Below Figure) as the material is extruded. Again, sections respond to the shape of the part. A further benefit of parison programming is reduced cycle time. The cycle time is governed by the thickest wall of the part and thus the slowest cooling time for the part. By removing unneeded material from thick areas or reducing overall wall thickness, leaving thick areas only where needed, molding cycle time can be improved.

Blow Pins/Needles

The parison is inflated with air during the blow molding cycle via blow pins. This can be done through the head with the blow pin attached to the mandrel, which has already been described and is typically used for bottles. For industrial and other products it may be more convenient or preferable to blow at the open end of the parison as the mold is closing (Below Figure)