Method and apparatus for injection blow molding an article with improved detail definition
AssigneeHercules Incorporated
InventorAime J. Gendron
Life of this patent
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Abstract
An injection blow molding apparatus and method produces articles by injecting a settable material at high pressure into the cavity of an injection mold to form a parison and then expanding the parison in a blow mold defining the configuration of the article. The injection mold defines intricate detail in the walls of the injection cavity and produces a parison with the detail formed thereon. Detail on the expanded portion of the parison is preserved in the blow mold and appears on the surface of the blown article without loss of definition.
Claims10
Apparatus for forming molded articles with improved raised detail definition comprising:
- a parison pin;
- a blow mold having an interior mold wall defining a cavity for blowing a parison on the parison pin and also defining the general exterior shape of an article formed by expanding the parison in the cavity at a blowing pressure;
- fluid pressure generating means cooperating with the parison pin and the blow mold for expanding the parison outwardly away from the pin and against the wall in the blow mold at the blowing pressure;
- an injection mold associated with the parison pin and blow mold, and having an interior mold wall defining a mold cavity in which the pin is inserted and in which a settable material is injected between the pin and the mold wall to form a parison for subsequent transfer to and expansion in the blow mold, the injection mold wall including at least one region defining an expandable part of the parison expanded in the blow mold and said region of the mold wall bearing recess defining means defining raised molding detail of definition and dimension finer than that formable in the blow mold under blowing pressure and conditions;
- the interior wall of the blow mold also including recess defining means in a region disposed in confronting relationship with the raised molding detail of the parison during blowing, the recess defining means defining a recess located and dimensioned to receive and preserve the raised molding detail when the parison is expanded in the mold at the blowing pressure;
- and
- injection means connected with the injection mold for injecting settable material into the mold at a pressure greater than the blowing pressure and sufficient to form the parison with the raised molding detail thereon.
In an injection blow molding apparatus having an injection mold in which a parison is formed by injecting a settable material at relatively high pressure into an injection mold cavity and a blow mold cavity defining a surface against which the transferred parison is expanded at a blowing pressure substantially less than the relatively high injection pressure, the improvement comprising:
- means within the injection mold and defining a portion of the injection mold cavity for forming on an exterior portion of the parison, said portion to be expanded in the blow mold cavity, raised detail features which are raised not substantially more than 0.1 inch above the surface of the parison and are incapable of definition in the blow cavity under blowing conditions;
- and
- recess means within the blow mold forming a portion of the blow mold cavity and defining a surface disposed during blowing adjacent said raised detail features formed on the parison in the injection cavity for cooperating with the parison to receive and preserve the raised detail features under blowing conditions.
Dependencies are inferred from the claim text.