Injection blow molding process

DETAILED DESCRIPTION The present invention relates to a method for making hollow plastic articles such as containers or bottles by first injection molding a preform or parison, bringing the temperature to an orientation range, transferring it to a blow molding station at which time the parison is initially removed from the transfer pin.
The parison is retained in position at the blow molding station for insertion of a core pin which axially extends and stretches the parison fully in one direction and then permits air to blow the parison to the desired extent within the mold in another direction to form the configuration of the finished blown article.
The article is then cooled and is transferred to an ejection station for removal from the apparatus or to a further work station.
The technique employed includes the steps of injection molding, axial expansion by stretching and then blow molding to obtain biaxial orientation of the finished product, article cooling and article ejection which are separate and related to one another but adapted to operate simultaneously.
The technique permits the injection molding of a parison and then transfer to a further station for first longitudinal expansion by stretching and then lateral expansion by blow molding to a finished configuration.
The finished product is then transferred to an ejection station for removal.
A further object is to provide a multiple station injection blow molding method in which two sets of core rod assemblies index at prescribed stations sequentially, with the first set cooperating in injection molding a parison and the second set axially expanding the parison to its full extent, blow molding the parison laterally to the selected full configuration, cooling the blow article and thereafter transferring the article to an ejection station or a further work station.
A further object is to provide a transfer injection blow molding method of employing close temperature controls for both heating and cooling where required to obtain parison molding to the desired configuration together with biaxial orientation